ANNUAL REPORT 1984 JAARVERSLAG CS>\^ - SMAT12

$Page 1: ANNUAL REPORT 1984 JAARVERSLAG CS>\^ - SMAT12$
NATIONAL INSTITUTE FOR MATERIALS RESEARCH (NIMR) NASIONALE INSTITUUT VIR MATERIAALNAVORSING (NIMN)

ANNUAL REPORT 1984 JAARVERSLAG 1 JULY 1963 - 30 JUNE 1984

1 JULIE 1983 - 30 JUNIE1984

CS>\^ - SMAT12

COUNCIL FOR SCIENTIFIC AND INDUSTRIAL RESEARCH WETENCKAPUKE EN NYWERHEIDNAVORSINGSRAAD

PRETORIA, South Africa PRETORIA, Suid-Afrika CSIR REPORT WNNR-VERSLAG

SMAT12 Published in 1964 by the National Institute for Materials Research CSIR PO Box 395 Pretoria 0001

SMAT12 Uitgegeedeurdie

Nasionaie Instituut vir Materiaalnavorsing WNNR

Posbus395 Pretoria 0001

ISBN 07988 3144 8 UDC 620.2:061.6.055.5(680)

Printed in 1984 in the Republic of South Afrca by the Graphic Arts Divisior. CSIR

In1984gedrukindie Republiek van Suíd-Afríka

deurdie Afdeling Grafiese Kunste

WNNR

CONTENTS INHOUD

National Advisory Committee for Materials Science and Engineering

Chief Director's Review

Highlights

RESEARCH ACTIVITIES Ceramics, Glass and Phase Studies

Electronic Materials Materials Characterization

Metals

SERVICES TO INDUSTRY AND OTHER ORGANIZATIONS Ceramics, Glass and Phase Studies

Electronic Materials Materials Characterization

Metals

RESEARCH SUPPORT ACTIVITIES Administration

General Appointments and retirements

Liaison and Information

PUBLICATIONS, REPORTS AND LECTURES Research Publications

6eneral Articles Institute Reports

Conference Proceedings Lectures presented at International Conferences

and National conferences Sundry 'ectures

WORKING GROUPS, COMMITTEES, COLLOQUIA AND VISITS Working Group Recommenjatlons

Visits Abroad Membership of International Committees

Membership of National Committees NIMR Collogula

Visiting Scientists and Students VIsHors from Abroad

NIMR Staff

2 Nasionale Advieskomitee vir Hateriaalwetenskap en -ingenieurswese

4 Oorsig van die Hoofdirekteur

19 Hoogtepunte

26 NAV0RSING8EDRYWIGHEDE 26 Keramiek, Glas en Fasestudies 41 Elektroniese Materiale 48 Materiaalkarakterisering 69 Metale 91 DIENSTE AAN DIE NYUERHEID EN ANDER ORGANISASIES 91 Keramiek, Glas en Fasestudies 91 Elektroniese Materiale 92 Materiaalkarakterisering 94 Metale

96 NAVORSIN6STEUN8E0RYWIGHEDE 96 Adminlstrasie 96 Algemeen 97 Aanstellings en uittredings 99 Skakellng en Inliqting

100 PUBLIKASIES, VERSLAE EN LESINGS 100 Navorsingspublikasies 102 Algemene Artikels 10? Instltuutverslae 108 Konferensieverrlgtinge 109 Leslngs aangebled by Internaslonale Konferensies 110 en Nasionale konferensies 113 Ander leslngs

115 WERKGROEPE, KOMITEES, COLLOQUIA EN BESOEKE 115 Aanbevelings van Werkgroepe 125 Buitelandse Besoeke 149 Lldmaatskap van Internasionale Kotnltees 149 Lidmaatskap van Nasionale Komitees 152 NIMN-Co11oqu1a 154 Besoekende Wetenskapllkes en Studente 155 Buitelandse Besoekers

158 NIMN-Per-oneel

NATIONAL ADVISORY CONHITTEE FOR MATERIALS SCIENCE AND ENGINEERING

C H A I R M A N Oft 6 HEYHWM Deputy President, CSIR

T E C H N I C A L A D V I S E R S

Ceramics, Glass and Phas» Studies PROF. J C A BOEYENS

Electronic Materials

Materials Characterization

Metals

OR R J HEDLAKE

PROF. R SUANEPOEL

PROF. J S VERHAAK

PROF. C J H SCHUTfE

PROF. H C SNYMAN

PROF. 6 G GARRETT

PROF. P J JACKSON

Department of Chemistry bV.verstty of the Witwatersrand Project Manager Anglo American Corporation of SA Ltd Department of Physics Rand Afrikaans University Department of Physics University of Port Elizabeth Department of Chemistry University of South Africa Department of Physics University of Port Elizabeth Department of Metallurgy University of the Witwatersrand Department of Physics University ot Natal

M E M B E R S

Universities

Government and Statutory Organizations

Industries

CSIR Institutes

Ex-Officio

PROF. J H VAN OER MERWE

OR G DE WET

OR H SCHEFFFL

OR P T WEDEPOHL

MR J C OE WAAL

DP N JOUGHIN

MR K PRINCE

DR N STUTTERHE1M

DR J R BULL

DR M S HUNT

DR J S V VAN Z'.OL

DR J 8 CLARK

Department of Physics University of Pretoria General Manager, Research ARMSCOR Assistant Chief Mechanical Engineer Design and Development South African Transport Services Director, Physical Metallurgy Council for Mineral Technology Managing Director Union Steel Corporation (of SA) Ltd Deputy Director General, Research Organization, Chamber of Mines General Manager, Planning and New Development, ISCOR Chairman, Telephone Manufacturers of 'A (Pty) Ltd Chief Director, National Chemical Research Laboratory, NCRL Chief Director, National Mechanical Engineering Research Institute NMERI Chief Director, National Physical Research Laboratory, NPRL Chief Director, National Institute for Materials Research, NIMR

NASIONALE ADVIESKOHITEE VIR HATERIAALHETENSKAP EN -IN5ENIEURSMESE

V 0 0 R S 1 T T E R OR 6 HEYMANM Adjunk-President, HNNR

T E G N I E S E A D V I S E U R S

Keramiek, Glas en Fasestudies

Elektroniese Materiale

Materiaalkarakterisering

Netale

PROF. J C A BOEVEHS

OR R J NEDLAKE

PROF. R SMANEPOEL

PROF. J S VERMAAK

PROF. C J H SCHUTTE

PROF. H C SNYNAN

PROF. 6 6 GARRETT

PROF. P J JACKSON

Departement Chemie Universiteit van die Mitwa'ersrand Projekbestuurder Anglo American Corporation of SA Bpk Oeptrtement Fisika Randse Afrikaanse Universiteit Department Fisika Universiteit van Port Elizabeth

Departement Chemie Universiteit van Suid-Afrika Departenent Fisika Universiteit van Port Elizabeth

Departement Metal lurgie Universiteit van die Hitwatersrand Departement Fisika Universiteit van Natal

L E 0 E

Universiteite

Ctaatsdiens en Statutêre Organisesies

N>werhede

WNNR-Institute

Ex-Officio

PROF. J H VAN OER MERWE

OR 6 OE WET

OR H SCHEFFEL

DR P T WEDEPOHL

MNR J C DE WAAL

DR N JOUGHIN

MNR K PRINCE

DR N STUTTERHEIM

DR J R BULL

DR M S HUNT

OR J S V VAN ZIJL

OR J B CLARK

Departement Fisika Universiteit van Pretoria

Hoofbestuurder, Navorsing KRY6KOR Assistent Hoof Meganiese Ingenieur Ontwerp en Ontwikkeling Suid-Afrikaanse Vervoerdienste Direkteur, Fisiese Metallurgie Raad vir Mineraaltegnologie

Bestjrende Direkteur Unie Staalkorporasie (van SA) Bpk Adjunk-Direkteur-Generaal, Navor-singsorganisering, Kamer van Mynwese Koofbestuurder, Beplanning en Nuwe Ontwikkeling, YSKOR Voorsitter, Telefoonvervaardigers van SA (Edms) Bpk

Hoofdirekteur, Nasionale Chemiese Navorsingslaboratorium, WNNR Hoofdirekteur, Nasionale Navorsingsiritituut vir Mtganiese Ingenieurswese, HNNR Hoofdirekteur, Nasionale Fisiese Navorsinqslaboratorium, WNNR

Hoofdirekteur, Nasionale Instituut v1r Materiaalnavorslng, WNNR

CHIEF DIRECTOR'S REVIEW

OORSI6 VAN DIE HOOFDIREKTEUR

The National Ins t i tu te for Materials Research

(NIMR) was established on 1 January 1983. The

f i r s t Annual Report covered the period 1 July

198? to 30 June 1983 and included the a c t i v i

t ies of the Materials Sciences Group, which

formed part of the National Phys io l iU:>earch

Laboratory (NPRL) durinq the period 1 July

1982 to 31 December 1982. Since the c-eation

of the NIMR the X-ray Photoelectron Spectros

copy f a c i l i t y of the Analytical Chemistry

Div is ion, National Chemical Research Labora

tory (NCRL), and the Metallurgy Division of

the National Mechanical Engineering Research

Ins t i tu te (NMERI) were transferred to the

NIMR, the la t te r on 1 August 1983. This 1983-

1984 Annual Report is the f i r s t to report on

progress since the consolidation of the NIMR.

GOALS Of THE NIMR

The primary qoal of the NIMR is to carry out

re;?drch and development in the arena of mace-

r i a l s science and materials engineering and to

s t r i ve for international excellence in th is

task.

Or J B Clark

Chief D i rec tor , NIMR Hoofdirekteur, NIMN

Die Nasionale Ins t i tuu t v i r Materiaaln .orsing

(NIMN) is op 1 Januarie 1983 gevestig. Die

eerste Jaarverstag het die '"ydperk 1 Ju l ie 1982

tot 30 Junie 1983 gedefc en het bedrywighede i n -

geslui t van die Materiaalwetenskapgroep wat v i r

die tydperk 1 Ju l ie 1982 t o t 31 Desefflber 1982

deel van die Nasionale Fisiese Navorsingslabo-

rator iun (NrNL) was. Sedert die s t ig t ing van

die NIMN is die X-straal fotoélektronspektro-

skopie f a s i l i t e i t van die Afdeling Anal i t iese

Chemie, Nasionale Chemiese Navorsinglaborato-

rium (NCNL), en die Afdel ing Metal lurgie van

die Nasionale Navorsingsinsti tuut v i r Meganiese

Ingenfeurswese (NNIMI) na die NIMN oorgeplaas,

1aasgenoemde op 1 Augustus 1983. Hierdie 1983-

1984 Jaarverslag is die eerste waari* verslag

oor vordering sedert die konsotldasle van die

NIMN gelewer word.

DOELNITTE WW DIE NIMN

Die primêre doelwit van die NIMN 1s om navor-

sing en ontwikkeling <» die arena van mate-

riaalwetenskap en materiaalingenieurswese te

onderneem en om in h ierd ie taak te strewe na

uitmuntendhelr' op internasionale gebled.

This primary goal includes the following spe

cif ic aims:

• To undertake research at>d development pro

jects in the national interest and, where

possible, to anticipate future needs, e.g.

in providing a sophisticated infrastructure

of active research for real nefds in mate

rials technology, in developing import re

placement technologies, in finding new ap

plications for South African raw materials,

e.g. chromium, manganese, platinum group

metals and zirconia, and promoting th* i r

export potential and wider u t i l i za t ion .

• To contribute, through research and the

rendering of specialized services, towards

developing and supporting industry, e.g.

establishing an expertise base for new or

existing materials processing techniques.

• To establish, staff , develop know-how and

maintain specialized fac i l i t i es at the

highest international level and to act in

an advisory capacity to promote materials

science and materials engineering in South

Africa.

• To establish good working relationships

with relevant Government departments,

other CSIR institutes, and statutory

organizations, to serve their needs and to

use the feedback from them regardinq new

areas of research.

• To liaise with universities In order to im

prove collaboration on such matters as re

search programmes and curricula develop

ment.

• To cooperate with overseas institutes/

organizations by exchanging knowledge and

scientists who are experts in their f i e ld ,

and by making scientific contributions to

International jvogrammes.

• To participate In the activities of inter

national organizations, such as the Inter

national Materials Congress, the Materials

Die hoofdoelwit sluit die volgende spesifieke

doelstellings in:

• On navo'sing- en ontwikkelingsprojekte in

die nasionale belang te onderneem en waar

moontlik toekomstige behoeftes vooruit te

loop deur 'n qesofistlkeerde infrastruktuur

van aktiewe navorsing te verskaf wat ware

behoeftes in materiaaltegnologie sal aan-

spreek; om invoervervangingstegnologieë te

ontwikkel en nuwe toepassing te vind vir

Suid-Afrikaanse grondstowwe, byvoorbeetd

chroom, mangaan, die platinum-groep metale

en sirkonia en om die uitvoer en groter

benutting van laasgenoemde te bevorêr.

• Om deur middel van navorsing en die lewering

van spesialisdienste by te dra tot die ont

wikkel ing van en steun aan die nywerheid,

byvoorbeeld deur 'n kundigheidsbasis ten op-

sigte van die tegnieke vir die verwerking

van nuwe of bestaande materiale te vestig.

• Om spesial isfastl i teite op die hoogste in -

ternasionale vlak tot stand te bring, te be-

man en te bedryf, om kundigheid te ontwikkel

en in 'n raadgewende hoedanigheid te dien om

materiaalnavorsing en -ingenieurswese in

Suid-Afrika te bevorder.

• Om goeie werkverhoudings met belanghebbende

staatsdepartemente, ander WNNR-institute en

statutêre liggame tot stand te bring, om in

hul behoeftes te voorsien en om hul insette

aan te wend ten opsigte van nuwe terreine

vir navorsinq.

• Om met die universiteite te skakel ten einde

samewerking oor aangeleenthede soos navor-

singsprogramme en leerplanontwikkeling te

bevorder

• Om met institute/organisasie' in die buite-

land saam te werk deur die ui trui l van kun

digheid en wetenskaplikes en deur bydraes

tot internasionale wetenskaplike programme

te lewer.

• Om deel te neem aan die aktiwiteite van

inte-nasionale orqanisasies, byvoorbeeld die

'International Materials Congress1, die

i i i Si ii

Research Society, the International Union

of Pure and Applied Physics (IUPAP) and the

International Union of Pure and Applied

Chemistry (IUPAC) etc .

• To develop a mul t id isc ip l inary environment

which allows sc ient is ts and engineers from

di f ferent backgrounds to collaborate close

ly and productively.

STRUCTURE AW MAJOR CHANGES HITHIN THE RINR

During 1983, the outstanding research done by

the Electrometallurgy Div is ion of the NIMR on

high energy density bat ter ies reached a c r i t

ical phase. Many of the research ideas had

been taken successfully through the early de

velopment phase, and i t was considered advisa

ble to involve industry in the next advanced

development/prototype phase. A new company

was consequently established fo r this purpose

under j o in t CSIR/SAIDCOR and Industr ia l spon

sorship. Or J Coetzer and the major i ty of his

research div is ion l e f t the NIMR and now form

the backbone of the new company of which

Or Coetzer was appointed as Í4anaging Director

on 1 January 1914. The NIMR w i l l continue to

be Involved in speci f ic contract research for

the company, and we wish our ex-colleagues

every success in th is d*nanding new venture.

The departure of most of the s ta f f of the

Electrometallurgy Div is ion, however, forced a

review of p r i o r i t i e s in th is area. A research

ac t i v i t y in so l id state electrochemistry was

retained and personnel and f a c i l i t i e s were

consolidated within the Ceramics, Glass and

Phase Studies Div is ion.

The creation of a Polymer Divis ion was men

tioned in the l')82 - 1983 Annual Report. The

f i r s t two candidates were selected to study

in the USA for PhO degrees in polymer science/

engine»'ing. They w i l l leave for the USA

in August 1984 and w i l l study at the

Massachusetts Ins t i tu te of Technology and the

Pennsylvania State Universi ty respectively.

Upon their return, a Polymer Research Division

w i l l be established. Addit ional staff members

w i l l be selected for spec ia l is t research/

technical t ra in ing during the course of the

'Mater ials Research Socie ty ' , die ' In terna

t iona l Union of Pure and Applied Physics

(IUPAP)' en d ie ' In ternat ional Union of Pure

and Applied Chemistry (IUPAC)', ens.

• Om 'n mul t id iss ip l inêre omgewing te ontwik-

kel wat wetenskaplikes en ingenieurs u i t

verski l lende mil ieus in staat sal stel om

nou en produktief saam te werk.

STRIRTUUR EN BELANGRIKE VERMBERINGE IN DIE NIMI

Gedurende 1983 net die hoogstaande navorsing

wat deur die Afdeling Elektrometallurgie onder-

neem is 'n k r i t i e ke fase bereik. Baie van die

navorsingsidees is suksesvol deur die vroeé

ontwikkelingsfase geneem en d i t is raadsaam

geag om die nywerheid by die volgende gevorder-

de ontwikkel ings-/protot ipe fase te betrek. 'n

Nuwe maatskappy wat gesamentlik deur UNKR/SAOKU

en die nywerheid geborg word, is gevolglik v i r

h ierd ie doel gest ig. Dr J Coetzer en die qroot-

ste gedeelte van sy navorsingsafdeling net die

NIMN verlaat en vorm tans die kern van die nuwe

maatskappy, waarvan dr Coetzer op 1 Januarie

1984 as Besturende Direkteur aangestel i s . Die

NIMN sal gemoeid bly met spesif ike kontrak-

navorsing v i r die maatskappy en ons wens ons

vorige kollegas a l le sukses toe met h ierd ie

uitdagende nuwe onderneming.

Die vertrek van die meeste van die personeel-

lede van die Afdeling Elektrcmetal lurqie het 'n

hersiening van p r i o r i t e i t e op hierdie gebied

genoodsaak. 'n Navorsingsaktiwiteit in vaste-

toestand-elektrochemie is behou en personeel en

f a s i l i t e i t e is in die Afdeling Keramiek, Glas

en Faseotudies gekonsoli deer.

Die s t i g t i ng van die Afdeling Polimere is in

die 1982 - 1983 Jaarverslag qemeld. Die eerste

twee kandidate is gekeur om v i r PhD-grade in

poli;neerwetenskap/-ingenieurswese in die VSA

te studeer. Hulle vertrek in Augustus 1984

na die VSA en sal onderskeidelik aan die

'Massachusetts Ins t i tu te of Technology' en die

'Pennsylvania State Universi ty ' studeer. Na hul

teruqkeer sal die Afdeling Pol*roeernavorsing

gevestig wnrd. Bykomende personeel sal qekeur

word v i r spesial is navors\ig-/teqn1ese op le i -

dinq gedurende die volqende twee jaar . Vanwee

6

next two years. Owing to the United supply of suitably trained manpower in polymer science «nd engineering in South Africa and the limited financial resources available fiom 6ovemment it will unfortunately take at least another four years to build an active Polymer Research Division.

The present structure of the NIHR is as follows:

die beperkte Suid-Afrikaanse mannekrag met geskikte opleidinq in polimeerwetenskap en -ingenieurswese en die beperkte finansiële hulp van owerheidsweë sal dit ongelukkig nog ten minste vier jaar cjur om 'n aktiewe Polineer-navorsingsafdeling op te bou.

Die NIMH se huidige struktuur is soos vo'g:

CHIEF DIRECTOR N00FOIREKTEUR

Dr J B Clark

INSTITUTE SECRETARY INSTITUUTSEKRETARIS

Mr/Mnr P S Mb'rsner

CERAMICS, GLASS AND PHASE STUDIES KERANIEK, GLAS EN

FASESTUDIES

Dr S Hart

1 LIAISON ft INFORMATION SKAKELIN6 t INLIGTING Mrs/Mev. M Swart

ELECTRONIC MATERIALS

ELEKTRONIESE MATERIALE

Dr H Booyens

MATERIALS CHARACTERIZATION

MATERIAAL-KARAKTERISERING

Dr J T Fourie

METALS

METALE

Dr N R Comins

1—. POLYMER

MATERIALS POLIMEER-MATERIALÍ

Dr J B Clark

A number of d iv is ional project team changes have been made in addition to the major structural changes previously mentioned.

In the Materials Characterizat ion Division a Surface Science Section was created under the leadership of Or C M Stander. This Section includes the Scanning Auger Microprobe (SAM), Ion Microprobe Mass Analyser (IMMA), Low Enerqy Electron D i f f r a c t i o n (LEED) and X~ray Photoelectron Spectrometer (XPS) f a c i l i t i e s with the associated manpower. Surface Science is expected to remain one of the major mater i a l s challenges and the Section ha* already established a number of promising i n t e r - d i v i sional projects.

In the Electronic Mater ia ls Oiv is ion, Or j H BassOf and Dr A P Botha have been given r e sponsibi l i ty for research on mercury cadmium t e l l u r i d e and gall ium arsenide respect ively .

Afgesien van die belangrike strukturele veran-deringe wat reeds gemeld i s , het 'n aantal ver-anderinqe aan projekspanne binne afdelings plaasgevind.

In die Afdeling Mater laalkarakter iser lng is 'n Oppervlakwetenskapseksie onder le iding van dr C K Stander geskep. Hierdie Seksie s l u i t die Skandeer-Auger-Mikrosonde (SAM), Ioonmikro-sonde-masia-anallseerder (IMMA), Lae-energie-e lek t ronJ i f f raks ie (LEED) en X -s t» la l fo toë lek -tronspektrometer (XFS) f a s l l i t e i t e en die ge-paardgaande mannekrag I n . Daar word verwag dat oppervlakwetenskap een van die belangrike mate-r laa lu i tdagings sal bly en die Seksie het reeds 'n aantal belowende Interafdel lngsprojekte aan die gang.

In die Afdeling Flektroniese Mater ia le is d ie verantwoordelIkheld v l r navorslng oor kwik kadmlum te11;r1ed en gall ium arsenied aan dr J H Basson en dr A P Botha onderskeidelfk opgedra.

In the Ceramics, Glass and Phase Studies Division new project teams on Electrochemistry and Properties of Materials have been established under Dr M r. Thackeray and Or I Sigalas respectively. The Electroche»-is f ry project team consists o x the personnel who remained at the NIMR following the transfer of the Electrometallurgy Division. Their long-term research direction is currently under review and the present work is aimed at lithium battery materials problem;. The appointment of a Properties of Materials project team has qiven special emphasis to an emerging body of work on the properties of materials at high pressures and high temperatures.

Two new member» of staff in the Metals Division were appointed as project leaders, v.z. Dr A Wells for Surface Treatments and Coatings and Dr A R Harding for Alloy Development.

MMMfiEMERT STYLE

The NIMJ? aims to create a team-orientated style of management. The Directorate is responsible for the overall management of the NIMR and includes the Chief Director and the heads of the divisions of the NIMR, viz. Dr H Booyens (Electronic Materials), Dr N R Comins (Metals), Dr J T Fourie (Materials Characterization), Dr S Hart (Ceramics, Glass and Phase Studies) and Mr P Morsner (Institute Administration!. A specialist team-building course attended by the Directorate has been most important in developing an institute strategy which allows collaborative priority setting. The principles of resource allocation have been applied successfully to a variety of diverse issues including laboratory space allocation which has lonq been a thorny subject.

Each research division comprises a number of project re.'arch teams which are. regarded as the major resource of the NIMR. Specialist traininq on personal time management, communications and institute strategy has been provided to project t >am leaders. Much has been done during the year to promote inter-

In die Afdeling Keramiek, Glas er» Fasestudies is nuMe projekspanne vir Elektrochemie en die Eienskappe van Materiale onderskeidelik onder die leiding van drr. M M Thackeray en I Sigalas gevestig. Die projekspan vir Elektrochemie bestaan uit personeel wat by die NIMN aanqebly net na die oorplasing van die Afdeling Elektro-metallurgie. Hul langtermyn navorsingsrigting word tans hersien en huidige werk is gerig op litiumbattery-materiaalprobleme. Die aanstel-ling van 'n projekspan vir die Eier.skappe van Materiale beklemtoon die groeiende hoeveelheid werk oor die eienskappe van materiale by hoë druk en hoë temperatuur.

Twee lede van die Afdeling Metale is as projek-leiers aangestel, naamlik dr A Wells vir Opper-vlakbehandelings en -bedekkings en dr A R Harding vir Legeringontwikkeling.

BESTUURSTYL

Die NIMN pooq om 'n spangerigte bf.-stuurstyl daar te s te l . Die Direktor^st wat veróntwoor-delik is vir die oorhoofse bestuur van die NIMN sluit in die Hoofdirekteur en die NIMN-afde-lingshoofde, naamlik dr H Booyens (Elektroniese Materiale), dr N R Comins (Metale) dr J T Fourie (Materiaalkarakterisering), dr S Hart (Kera.niek, Glas en Fasestudies) en m,- P Morsner (Instituuta^ministrasie). 'n Spesialis spanboukursu? wat deur die Direkloraat bygewoon is, was van groot belang in die ontwikkeling van 'n instituutstrategie vir gesamentlike prioriteitbepaling. Die beginsels vir die toe-kenning van bronne is suksesvol op 'n verskei-denheid uiteenlopende aangeleenthede toegepas, insluitende die toekenning van laboratorium-ruimte wat reeds 'n qeruime tyd 'n netelige onderwerp was.

Elke navorsingsafdeling bestîn uit 'n aantal projeknavorsingspanne wat as die belangrikste hulpbron en aksie-area van die NIMN beskou word. Spesialisopleidinq oor persnonlike tyd-bestuur, kommunikasie en instituutstrateqie is aan proje!:spanleiers verskaf. Gedurende "lie jaar is bale gedoen om samewerking fussen afde-

I divisional collaboration and project leaders have a weekly seminar series to promote the exchange of infontation. The Directorate pays regular visi ts to divisions to discuss problem and new ini t iat ives. In addition, the Directorate and project leaders met approximately th-ee times annually to provide a forum for the discussion of Institute problems and opportunities. Further training in research project management wil l be provided during 1985.

INTEMMTIOML MO LOCAL COLL A0CMT ION

• International

I t is v i ta l to the NIMR to stimulate International collaboration in the f ie ld of materials research. Collaboration has been promoted in a number of areas which include the following:

• Person-to-person collaboration by means of overseas visits by NIMR* personnel. Also, leaoing overseas researchers are encouraged to v is i t the NIMR for periods ranging from two weeks co one year. A complete l i s t of visitors Is provided elsewhere, but special mention should be made of a three week visi t to South Africa by Prof. Morris Cohen from the Massachusetts Institute of Technology. Prof. Cohen played a major role in discissions and decisions on currant and future research activities at the NIMR. The positive impact of his v is i t wi l l long be fe l t in the South African mater ials community.

• Specialist research needs were also covered by obtainlnq advisory Inpu'. from the following International visitors:

Prof. B-Z Weiss, Technlon • Israel Prof. D Elwell, Stanford UnlversUy, USA Dr B J Fltrpatrlck, Philips Laboratories

N.Y., USA Prof. H Rawson, formerly from Sheffield

University, UK.

lings te bevorder. Die u i t ru i l van inl igt ing word bevorder deur "n weeklikse seminaar-reeks vir p ojekleiers. Die Direktoraat besoek afde-l in,s gereeld om problems en nuwe inisiatiewe te bespreek. Daarbenewens vergader die Direk-toraat en projekleiers ongeveer drie maal per jaar ten einde 'n forum daar te stel vir die bespreking van probleme en geleenthede. Ver-dere opleiding in navorsingsprojekbestuur sal in 1985 verskaf word.

INTERMSIOMLE EN PLMSLIKE SJMENEMClK

• Internasionaal

Dit is v ir die NIMN uiters belangrik om internasionale sameworking op die gebied van materlaalnavorsing aan te wakker. Samewer-king is op 'n aantal terreine bevorder, wat onder andere die volgende ins lu i t :

• Sar.ewerking van persoon tot persoon is bevorder deur middel van oorsese besoeke deur NIMN-personeel. Ook word toonaange-wende oorsese besoekers aangemoedig or" die N1KN te besoek vir tydperke wat wissel van twee weke tot een jaar. 'n Volledige lys van besoekers verskyn elders, maar spe-slale mtlding moet gemaak word van 'n besoek deur prof. Morris Cohen van die 'Massachusetts is t l tu te of Technology' wat S'iid-Afrika vir drie weke besoek het. Prof. Cohen het 'n belangrike rol gespeel in bespreklngs en besluite oor huidige en toekomstige navorsingsaktiwlteite van die NIMN. Die posltiewe uitwerklng van sy besoek sal nog vir 'n lang tydperk deur die Su1d-Afr1kaanse materiaalgemeenskap ervaar word.

• Speslalisnavorsinqsbehoeftes is ook gedek deur raadgewende insette van die volgende Internasionale besoekers:

Prof. B-Z Weiss, Technlon - Israel Prof. D Elwell, Stanford Universltelt, VSA Or B J Fltzpatrlck, Philips Laboratories,

N.Y., VSA Prof. H Rawson, voorheen van Sheffield

Unlversltelt, VK

Collaborative research programmes which

should last at least three years have

been established with a number of re

search laboratories in Israel and the

Republic of China. These programmes form

part of international exchange agree

ments with those countries. The NIMR

has sponsored research programmes at

Stanford Research Institute, Gorham, and

the Massachusetts Institute of Technolo

gy in the USA. These programmes are de

signed to keep the NIMR abreast of the

latest international trends and in i t i a

tives and thus enable the Institute to

focus i ts own research on the most im

portant areas.

• Navorsingsproqramme Is in samewerking met

'n aantal navorsingsTaboratoria in Israel

en die Republiek van China aangepak en sal

ten minste drie jaar duur. Hierdie pro

gramme vorm deel van internasionale u i t -

ruilooreenkomste met daardie lande. Die

NIMN het geborgde navorsingsprogramme by

'Stanford Research Ins t i tu te ' , Gorham, en

die 'Massachusetts Institute of Technolo

gy' in die VSA. Hierdie programme is ont-

werp om die NIMN op hoogte te hou van die

jongste internasionale tendense en inisia-

tiewe en om die Instituut sodoende in

staat te stel om eie navorsing op die mees

belangrike areas te r ig .

• The NIMR arranged a Workshop on Semicon

ductor Materials for representatives

from research laboratories in the

Republic of China and South Africa. A

number of cooperative init iat ives re

sulted from the Workshop.

Die NIMN het 'n 'Workshop on Semiconductor

Materials' vir verteenwoo«-digers van na-

vorsingslaboratoria in die Republiek van

China en Suid-Afrika gereêl. 'n Aantal

samewerkingsinisiatiewe het uit hierdie

werksessie voortgespruit.

• A cooperative programme involving labo

ratories from Sweden, Canada, Japan,

Federal Kepublic of Germany and the NIMR

was ini t iated. The aim of the programme

is to compare the various methods for

measuring the thermal conductivity of

materials at high temperatures and

pressures.

'n Kooperatiewe program wat laboratoria in

Swede, Kanada, Japan en die Bondsrepubliek

van Duitsland inslui t , is in die lewe ge-

roep. Die doel van die program is om ver-

skeie metodes vir die meting van die ter-

miese geleiding van materiale by hoe druk-

ke en temperature te vergelyk.

The initiatives mentioned above are designed

to gain international recognition for the

NIMR and also to serve as a South African

window for international developments in the

f ield of materials science and engineering.

Bogemelde inisiatiewe is opgestel om Interna

sionale erkenning vir die NIMN te verwerf en

ook om as 'n Suid-Afrikaanse venster vir Inter

nasionale ontwlkkeling op die gebied van mate-

rfaalwetenskap en -inqenieurswese te dien.

Local • Plaaslik

• The NIMR plays a national role and the local init iatives do not have a lower priority than the international in i t ia tives mentioned above. A number of special initiatives have been taken to promote local collaboration.

• Die NIMN speel 'n nasionale rol en die plaaslike Inisiatiewe is nie van minder belang as bogemelde internasionale inisiatiewe n1e. 'n Aantal buitengewone fntsia-tiewe Is geneem om plaaslike samewerkinq te bevorder.

• A national study was launched by the

Study Committee for Materials Science • 'n Nasionale ondersoek is deur die Ctudle-

komitee vir MaterlaalwetensMp en -inge-

10

and Engineering in South Africa. The groundwork for the study Mas undertaken oy members of the NIMR in associate or with Prof. 6 G Garrett of the University of the Witwatersrand. The rhairman is Or G Heynann. The study is a national venture and wil l focus on the role of materials science and engineering in South Africa. The NIMR will be involved actively and the findings are expected to provide, amongst ether things, an important long-term view of tne South African research needs which should be addressed by the NIPR.

• National conferences/symposia that have been arranged by the NIMR include the Materials Symposium and the Crystal Growth Conference, both held in November 1983.

• Education of graduates and technical staff in the f ie ld of materials science and engineering is vital to the long-term needs of the entire national effor t . The NIMR has commitments to provide staff members to present courses at universities and technikons. A number of courses/lectures have already been presented and others are being planned. Enhancement of research collaboration between the people concerned is expected.

• Interaction and contact has been established with professional bodies involved either directly or Indirectly in the f ie ld of materials. These contacts are at present In the formative stages, but i t is envisaged that they w i 1 ! develop Into Important links In the long term.

• Being a new Institute, development of Interaction with other CSIR Institutes 1s Important, This process has been I n i tiated by visits to/from the Nulonal Building Research Institute, the National Institute for Transport and Road Research, the Chemical Engineering Research Group and the National Chemical

nieurswese in Suid-Afrika gelocds. Lede van die NIMN in medewerking met prof. 6 6 6»rrett van die Universiteit van die Witwatersrand het die aanvoorwerk vir die ondersoek gedoen. Dr G Heymann is die Voorsitter. Die ondersoek is 'n nasionale poging en sal op die rol van die materi-aalwetenskap en -inoenieurswese in Suid-Afrika gerig wees. Die NIMN sal aktief hiermee gemoeid wees en na verwagtig sal die bevindinge onder andere 'n belangrike langtermyn vooruitskouing gee van Suid-Afrikaanse navorsingsbehoeftes wat deur die NIMN aangespreek behoort te word.

• Nasionale konferensies/simposia wat Jeur die NIMN gereél i s , sluit die Materiaal-simposium en die Konferensie oor Kristal -groei in , wat albei in November 1983 gehou is.

*e ooleiding van qegradueerdes en tegnie-se personeel op die terrein van die mate-riaalwetenskap en -inoenieurswese is oor die lang termyn uiters belangrik vir die behoeftes van 'n nasionale poging. Die NIMN het homself verbind om personeellede beskikbaar te stel vir die ionbieding van kursusse by universlteite en technikons. 'n Aantal kursusse/lesings het reeds plaasgevlnd en ander word beplan. Daar word verwag dat dit tot 'n verstewiglng va» lavorsingsamewerking tussen betrokke persone sal l e i .

• Interaksle en kontak is bewerkitellig met professlonele liqgame wat direk of indirek met die gebied van materiaalnavorsing gemoeid Is. Hierdie kontakte Is tans in die vormingsfases maar daar word verwag dat dit irettertyd in belangrike skakels sal ontwikkel.

• Synde 'n nuwe Instituut Is die ontwlkke-Ung van Interaksle met ander WNNR-1nst1-tute belangrik. H1erd1e proses 1s aan die gang gesit deur besoeke van/aan die Nasionale Instituut v1r Bounavorslng, die Nasionale Instituut vir Vervoer- en Padna-vorslng, die Navorslngsgroep In Chemlese Ingenieurswese en die Nasionale Chemlese

11

Research Laboratory. Visits to other institutes ar? planned, while the established interaction will be maintained.

RESEARCH FACILITIES

• Hew Research Facilities

The NIMR has an excellent spectrum of research facilities. Special mention should be made of the following new developments:

• Scanning Mass Spectrometer

The Institute has recently acquired an ultra-high resolution scanning mass spectrometer to satisfy the need for a rapid and accurate analysis service for materials. The instrument is the Vacuum Generators' ZAB mass spectrometer equipped with plasma discharge, fast atom bombardment and electron impact/chemical ionization ion sources. The mass spectrometer is interfaced to a DEC POP 11/24 data system for rapid processing of results. The central processing unit has one megabyte of random access memory to accommodate the very sohisticated control and data acquisition systems. The mass spectrometer wiT. be capable of multi-element analysis with an accuracy of a few percent and will reduce total analysis time *>y at least an order of maqnitude when compared to the present spark source mass spectrograph.

• X-ray Di f f rac t ion

The X-ray d i f f rac t i on f a c i l i t i e s of the Ins t i tu te are being upqraded. A f u l l y automated diffractometer with a capabi l i ty for stress/texture analysis and an X-ray topograph for the study of bulk and surface defects have been purchased. The present powder X-ray d i f f r ac t i on f a c i l i t y is also being expanded to allow in s i tu high pressure studies of materials using a diamond anvil c e l l .

Navorsingslaboratorium. Besoeke aan ander i ns t i t u te word beplan en gevestigde nter-aksie sal in stand qehou word.

RAV0RSIR6SFASILITEITE

• Rune Ravorsingsfasiliteite

Die NIMN beskik oor 'n uitmuntende spektrum na-vo rs ings fas i l i t e i t e . Die voigende nuwe ontwik-kelinge verdien spesiale vermelding:

• Skandeer Massaspektrometer

Die Ins t i tuu t het otilangs 'n skandeer massa-spektrometer met ultrahoë oplosvermoë aange-skaf om in die behoefte aan 'n v in i i ig* en akkurate analise-diens v i r materiaal '.e kan voldoen. Hierdie instrument is die 'Vacuum Generators' se ZAB massaspektrometer wat toegerus is met plasma-ontlading-, vinnige atoombombardement- en elektronbotsing/che-miese ionisasie ioonbronne. Die massaspektrometer is gekoppel aan 'n DEC PD? 11/24 datastelsel v i r vinnige verwerking van re-sul tate. Die sentrale verwerkingseenheid

een megagreep ewetoeganklike geheue ten einde die hoogs gesofistikeerde kontrole en data-aanwinsstelsels te kan huisves. Die massaspektrometer sal in staat wees tot meer-element analise met akkuraatheid van 'n paar persent en sal in vergelyking met die huidiqe vonkbronmassaspektrograaf tota le analisetyd met ten minste 'n ordegrootte verminder.

• X-s t raa ld i f f raks ie

Die X-s t raa ld l f f raks ie f a s i l i t e i t e van die Ins t i tuu t word tans opqradeer. 'n Ten voi le outomatiese diffraktometer wat In stoat is tot spanning-/tekstuuranalise en 'n ;:-straal topograaf v i r die studie van grootmaat- en oppervlakdefekte is aanqekoop. Die huidige poeier X-s t raa ld i f f raks ie f a s i l i t e * ' . word ook uitgebrei v i r 1n s i tu hoëdruk-ondersoek? van materiale met behulp van 'n diamantdruk-se l .

• Electronic Characterization Facility • Elektroniese Karakteriseringsfasiliteit

Over the past year the Electronic Materials Division has established an electronic characterization facility for the routine determination of electron and ho!.; concentrations and mobilities, charqe carrier lifetimes, materials resistivity and a variety of electronic junction properties.

• Workshop

Specialist workshop facilities are critical to the research support needs of the NIMR. During the present year, the NIMR in collaboration with the Technical Services Department of the CSIft established the NIMR branch workshop. A team of five instrument makers under the capable leadership of Mr N Moerman has provided a very efficient service.

In addition to the new facilities described above, there are a variety of smaller items worth mentioning. These include

• a creep/stress rupture machine for high temperature mechanical testing

• mlcrohardness and scratch tester

• spark machine for metal sample preparation

ion-beam thinner for transmission electron microscope sample preparation

• computer control syst.-ms for the Instron mechanical testing facility and vacuum induction melting equipment

thermal conductivity apparatus for measurements up to 1 uOO = C

• visible light spectrometer and laser for ruby pressure scale calibration

• Infrared spectrophotometer system adapted for transmission studies at controlled temperatures down to 10 K

• infrared microscope operating at up to 3 wn wavelengths.

Gedurende die afqelope jaar net die Afdeling Elektroniese Materiale 'n elektroniese karakteriseringsfasillteit tot stand gebring vir roetinebepalings van elektron- en holte-konsentruies en -mooiliteite, ladingsdraer leeftye, materiaalresistiwiteit en 'n ver-skeidenheid elektroniese krpoeleienskappe.

• '..erkpl aas

bt^pisialiseerde werkplaasfasiliteite ter ondersteuning van die navorsingsbehoeftes van die NIMH is van kritieke belang. Gedurende die huidVe jaar het die NIMH in same-werking met die Departehent Tegniese Dienste van die UHNR die NIMH-takwerkplaas gevestig. 'n Span bestaande uit vyf instrumentmakers onder die bekwame leiding van mnr H Moerman het 'n bale doeltreffende diens gelewer.

Afgesien van die nuwe fasillteite wat hierbo beskryf is behoort 'n verskeidenheid kleiner items ook gemeld te word, onder andere

• 'n kruip-/spanningbreukmasjien vir hoëtempe-ratuur meganiese toetsing

• mikrohardheid- en kraptoetser

• vonkmasjien vir metaalmonstervoorbereiding

• ioonbundelverdunner vir voorbereiding van monsters v1r die transmissie-elektronmikro-skoop

• rekenaarbeheerstelsels vir die Instron meganiese toetsfasllitelt en vakuuminduksie smelttoerustlng

• termiese geleidlngsapparaat vir bepallngs tot by 1 000 3C

• sigbare ligspektrometer en laser vir robyn-drukskaal kallbrasie

• Infrarooi spektrofotometerstelsel wat aange-pas is vir transmisslestudies by beheerde temperature so laag as 10 K.

• Infrarool-mikroskoop wat tot by 3 urn qolf-lengtes werk.

• Older tesearch Faci l i t ies • Oner Navorsinosfasiliteite

One if the most serious problems facing the NIMR relates to aging research f a c i l i t i es which need replacement. The problem is especial ly serious owing to the d i s turbing trend over the past tew years of drast ic price increases for sophisticated capital equipmen..

Special mention should be made of the transmission electron microscope f a c i l i t i e s . Two transmission electron microscopes, of which the most modern is eight years o l d , are avai lable at the NIMR. Developments over the last f i ve years in so-called analyt ical electron microscopy have led to a t o t a l l y new design of electron microscopes. This type of instrument is capable of extract ing unparalleled i n formation concerning the chemical composit ion and crystal lographic nature of mater i a l s . In par t i cu la r , under suitable sample condit ions, i t is capable of determining element concentration gradients near grain boundaries over distances as small as 10 nm and accurate 1 at ice parameters in localized volumes of 10 nm diameter. The present l ick of such an instrument is hampering progress in many areas of mater i a l s research wi th in the NIMR since the characterization of advanced materials re quires highly local ized information on composition to an ever increasing degree.

The Surface Science Section inheri ted the SAM, IMKA, LEED and XPS. Of these only the SAM is a modern piece "'. equipment. For the others electronic control c i r c u i t ry is s t i l l valve-based. Furthermore a l l f a c i l i t i e s are single technique ins t ru ments which have undergone extensive modif i c a t i o n . Maintenance costs are high, and technicians are required fu l l - t ime to keep equipment operat ional. Or C M Stander was asked to review the ent i re s i tuat ion and his recommendations appear elsewhere. In b r i e f , the Surface Science Section w i l l retain the single technique equipment for the foreseeable fu ture , but w i l l tend to move towards the po ten t ia l l y much more

Een van die ernst igste probleme waarmee d ie NIMN te kanpe net, hou verb and met d ie ver-oudering van navors ings fas i l i te i te wat ver-vang behoort te word. Die probleem i s veral ernst ig weens die onstellende neiging die afgelope aantal jare to t drastiese pryssty-gings in gesofist ikeerde kapi taal toerust ing.

Die transmissie-elektronmikroskoop f a s i l i -t e i t e moet in die besonder gemeld word. Twee transmissie-elektronmikroskope i s by die NIMN beskikbaar, waarvan die modernste een reeds agt jaar oud i s . Ontwikkelings gedurende die afgelope vyf jaar in die soge-naamde anal i t iese elektronmikroskopie het t o t 'n algehele nuwe ontwert van elektron-mikroskope ge le i . Hierdie t ipe instrument is daartoe in staat om cigeewenaarde i n l i g -t i ng rakende die chemiese samestelling en k r i s ta l l og ra f iese aard van materiale te ont-t rek . In besonder kan d i t onder geskikte monstertoestande, gradiënte van elementkon-sentrasie naby korrelqrense oor afstande so k le in as 10 nm, asook akkurate roosterkon-stante in gelokaliseerde volumes van 10 nm deursnee bepaal. Die huidige gebrek aan so 'n instrument strem vordering op t a l l e ge-biede van materiaalnavorsing in die NIMN aanqesien die karakterisering van gevorderde materiale in stygende mate hoogs p->loka1i-seerde i n l i n t i ng betreffende samestelling vereis.

Die Seksie Oppervlakwetenskap het die SAM, IMMA, LEED en XFS qeërf. Van h ierd ie is slegs die SAM 'n moderne stuk toerust ing. Vir die ander is die stroombaan v i r e lek t ro -niese beheer nog op buise gebaseer. Verder Is al die f a s i l i t e i t e enkel tegniek- instru-mente wat groot l lks verander het. Onder-houdskoste is hoog en tegnici word voltyds benodig om toerust'.ng in werkende orde te hou. Dr C M Stander Is versoek om die hele s i tuasie in oenskou te neem en sy aanbeve-l lngs verskyn elders. 0m op te som, die Seksie Oppervlakwetenskap sal die enkeit?q-nlek-toerust lnq v i r die voorsienbare toeko'" behou, maar beooq 'n kragtiger s te lse l waar mult i teqniek- fasi 1 I t e i t e In een masjlen

powerful system of multitechnique f a c i l i

t ies integrated on one machine. This w i l l

make better use of f a c i l i t i e s and manpower

in attackinq materials problems.

In order to carry out a successful a l loy

development programme i t is essential to

have suitable processing equipment ava i l

able. The present r o l l i n g m i l l , although

suitable fo r some general purpose work,

was bu i l t in 1952 and has some major l i m i

ta t ions . I t would be uneconomic to develop

th is un i t , and a versat i le instrumented

m i l l to sui t future requirements is under

consideration.

RESEARCH INITIATIVES

During 1983, the ent i re process of research

programme i n i t i a t i r i , implementation, review

and eventual u t i l i z a t i o n was changed.

Individual research workers, project teams

and project leaders were recognized as the

source of research ideas. An internal and

external peer review system for reviewing

project proposals was implemented to ensure

that the research programmes form part of the

NIMR's research strategy. In b r i e f , project

teams develop project proposals, which are

reviewed by colleagues within their d iv is ion

and eventually by head» of divisions and pro

ject leaders from other d iv is ions. Once th is

process has been completed, the research od-

visory panel for each div is ion provides f u r

ther scrutiny and input. The annual research

programme of the NIMR is then drawn up f.o i n

clude the proposals that were amended and/or

accepted during the preceding review process

and are submitted to the National Advisory

Committee for Materials Science and Engineer

ing for f ina l approval.

The formal advisory structure of the NIMR is

shown overleaf. The diagram also highl ights

the funct irn of the working groups that pro

vide the NIMR and other decision-makers wit i i

concise reports on specific topics re la t inq

to new research i n i t i a t i v e s , ident i f i ca t ion

geïntegreer word om sodoende f a s i l i t e i t e en

mannekraq beter te benut by die aandurf va.°

materiaalprubleme.

Ten einde 'n suksesvolle legeringsontwikke-

lingsprogram u i t te voer is die beskikbaar-

heid van geskikte prosesseringstoerusting

noodsaaklik. Die huidige walswerk wat wel

v i r bepaalde algemene doeleindes geskik i s .

is in 1952 gebou en het belangrike beper-

kinge. Dit sou onekonomies wees om hierd ie

eenheid te ontwikkel er, 'n veelsydiger geïn-

strumenteerde meul om aan toekomstige be-

hoeftes te voldoen, word tans oorweeg.

MVORSIRGSINISIATIEK

Gedurende 1983 is die hele proses van i n i s i e -

r i n q , implementering, hersiening en u i te inde-

l i ke benuttinq van die navorsingsprogram gewy-

Individuele navorsers, projekspanne en projek-

le iers is geident i f iseer as die bron van navor-

singsidees. 'n Stelsel van interne en eksterne

beoordeling deur qelykes is geimplementeer om

projekvoorstel le te beoordeel ten einde te ver-

seker dat die navorsingsproqranwne deel vorm van

die NIMN se navorsingstrategie. K o r t l i k s , pro-

iekvoorstel le word deur projekspanne ontwikkel ,

daarna deur kollegas in die Afdeling beoordeel,

en ten laaste deur hoofde van afdelings en pto-

jek le ie rs van ander a fde l i rgs . Sodra h ierdie

proses afgehandel i s , doen die navorsingscd-

viespaneel / i r elke afdel ing verdere hersiening

en gee inset te . Die jaa r l i kse navorsingsprogram

van die NIMN word dan opgestel met i ns lu i t i ng

van voorste l le wat tydens die voriqe proses

verbeter en/of aanvaar is en word dan aan die

f'asionale Advieskomitee vir Materiaalnavorsing

en -inqenieurswese v i r f ina le goedkeuring voor-

q e l i .

Die formele raadqewende struktuur van die NIMN

word op die volgende bladsy uiteengesit . Die

diagram toon ook die funksie van die werkgroepe

wat ci.• NIMN en ander bcslultnemers voorsien

van kort verslae oor spesifieke onderwerpe wat

verband hou met nuwe navorsingsinislat lewe, die

NATIONAL ADVISORY COMMITTEE FOR MATERIALS SCIENCE AND ENGINEERING

FUNCTIONS

Considers the Materials Science and Engineerinq activities in South Africa, identifies qaps and promotes initiatives to solve problems and close gaps.

Oecides on research directions and research policy for the NIMR.

Monitors research progress within the NIHR to ensure that the research is in line with the Research Programme and that it is of suitably high standard.

NASIOMLE ADVIESKOMITEE VIR HATERIAALNETENSKAP EN -INGENIEURSUESE

FUNKSIES

OorMeeq bedrywiqhede ten opsigte van Materiaalwetenskap en -inqenieurswese in Suid-Afr ika, iden-t i f i s e e r leentes en bevorder in is iat iewe om probleme op te los en leemtes te v u l .

Besluit op navorsingsrigtinqs en -b«leid v i r die NIMN.

Kontroleer navorsingsvorderinq binne die NIMN ten einde te verseker dat navorsinq in ooreenstem-rainq met die Navorsinqsprogram uitgevoer word en van toepaslike hoë standaard i s .

RESEARCH ADVISORY PANELS: DETAILED TECHNICAL INPUT

FUNCTIONS

• To provide in-depth technical advice regarding ex is t ing research projects in the Division concerned. This includes attending technical report meetings twice a year.

• To provide in-depth technical advice reqardinq the future research proqramme of the div is ion concerned. This is done by face-to-face evaluation of proposed research projects during the development of the annual research programme.

• To provide the Advisory Committee with reports on the work underway and present the major problems facing the Division to the Advisory Committee.

NAVOXSIWSSAOVIESPANELE: SPESIALE TE6NIESE INSETTE

FtiNKSIES

• 0m die betrokke Afdelinq van grondiqe tegniese raad ten opsigte van bestaande navorsingsprojekte te bedien. Dit sluit die bywoning van tegniese .erslagvergaderings twee maal per jaar in.

• Om die betrokke Afdeling van grondiqe tegniese raad ten opsigte van toekomstige navorsingspro-qramme te bedien. Dit word qedoen deur reqstreekse beoordeling van voorgestelde navorsingsprogramme tydens die ontwikkeling van die jaarlikse navor-sinqsproqram.

• Om die Advieskomitee van verslae te voorsien en om die belanqrikste probleme waarmee die Afdelinq te kampe het aan die Advieskomitee voor te lê.

t WORKING GROUPS: SUPPORT ACTIVITY

Working groups are commissioned to study particular problems in depth and to report back to the Advisory Committee on recommended action. Their goals are specific and may relate to Institute matters or national problems. Members are appointed to serve for the duration of the studies and include Institute staff members, members of Technical Advisory panels and outsiders to enable maximum benefit from in-depth technical discussions. Present working groups are active on:

• Materials engineering and processing • Wet chemical laboratory requirements • Refractory research • Mould laboratory for investment casting • Crystal growth • Rapid solidification processing • Accommodation needs of the NIMR.

MERKGROEPE: 0N0ERSTEUNIN6SBE0RYWIGHEDE

Deeqlike bestuderinq van bepaalde probleme en aanbe-velinq van 'n oplossinq aan die Advieskomitee word aan Werkqroepe opgedra. Hul doelwitte is van spesi-fieke aard en kan verband hou met Instituutprjbleme of probleme op nasionale vlak. Lede word vir die duur van die ondersoek aangestel en sluit Instituut-personeel, lede van Teqniese Adviespanele en buite-staanders in ten einde maksimum voordeel uit grondiqe tegniese besprekings te verkry. Werkqroepe is tans bedrywig met:

• Materiaalinqenieurswese en -prosessering • Sehoeftes vir 'n nat chemiese laboratorium • Navorsinq oor vuurvaste materiale • Gietvormlaboratorlum vir presisieqietinq • Kristalgroei • Vinniq stollinqsprosesserlng • Huisvestingsbehoeftes van die NIMN.

EXTERNAL CONSULTANTS: SUPPORT ACTIVITY

External vnsultants (normally top international researchers) are appointed to present specialist information (e.q. future of glass research) when this is not available locally at a suitable s'andard. Consultants are appointed by the Institute with Executive approval, for a specific task.

KONSULTANTE VAN BUITE: ORDERSTEUNINGSBEORVNIGHEDE

Konsultante van buite (qewoonlik vooraanstaande internasfonale navorsers) word aangestel om spesialislnligting te lewer (byvoorbeeld die toekoms van glasnavorsing) indien soda-niqe inlfqtinq van 'n geskikte standaard nie plaaslik bekombaar is nie. Konsultante word, met die goedkeurinq van Hoofbestuur, deur die Instituut vir 'n spesifiekp taak aanqestel.

16

of equipment needs e*c. Members are from the

N1HR, un ivers i t ies , ".tatutory bodies, indus

t r y and also include overseas advisers.

HIM STAFF NMIEVCKftTS

The Chief of the Navy's Commendation was

awarded to Dr J B Clark personally and also

to the s ta f f of the NIMR for excellent ser

vice to lie South African Navy.

I t was an especially proud moment for the

NIMR when Or Jonan Coetzer received one of

the f i r s t three CSIR annual gold medal awards

for excellence.

Or Angus I Kingon was awarded the Solid State

Physics and Materials Sciences Special ist

Group award for the best paper resul t ing from

a thes is . The publication was en t i t l ed

'S in te ' ing of PZT ceramics'; part 1 : 'Atmos

phere c o n t r o l ' ; part 2: 'Ef fect of PbO-

content on densif icat ion k i n e t i c s ' .

Mr P D Hicks, presently seconded to the

Department of Metallurgy at the University of

the Witwatersrand to do his MSc degree, was

awarded the Chamber of Mines Research Scho

larship and Gold medal for 1983.

The importance of individual research workers

cannot be overemphasized. The NIMR has a

number of undergraduate and post-graduate

bursars. Their education is essential to the

long-term future of the I ns t i t u te . Bursars

are assigned to divisions and are encouraged

to spend their vacations working at the NIMR.

The achievements of these bursars have been

most rewarding but special mention should be

made of Mr N Chetty. He obtained f i r s t class

passes and cer t i f i ca tes of merit in both his

f i n a l year BSc degree subjects, v i z . Applied

Mathematics I I I and Physics I I I . His vaca

t ion work at the NIMR is of an outstanding

standard and he has been awarded a CSIR post

graduate bursary.

iden t i f i kas ie van toerustingbehoeftes ens. Lede

is u i t die NINN, un i ve rs i t e i t e , statutêre orga-

nisasies en die nywerheid afkomstig en s l u i t

oofc buitelandse raadqewers i n .

•INR-KltSMKELFRESTNSIES

Toekennings van die Hoof van die Vloot is «an

dr J B Clark per soon l i k gemaak, asoofc aan die

personeel van die NIMH v i r uitstekende diens

aan die Suid-Afrikaanse Vloot.

Die NIMN het 'n besondere t ro tse oomblik beleef

toe dr Johan Coetzer een van die eerste dr ie

jaa r l i kse UMIR goue medalje-toekennings v i r

uitmuntendheid ontvang het .

Or Angus I Kingon het die toekenning van die

Vrstetoestand-Fisika en Materiaalwetenskap Spe-

sial isgroep ontvang v i r die beste publikasie

wat u i t 'n verhandeling voortgespruit het. Die

t i t e l van die publikasie is 'S inter ing of PZT

ceramics; par t . 1 ' : 'Atmosphere con t ro l ; par t .

2 ' : 'Ef fect of PbO-content on densi f icat ion

k i n e t i c s ' .

Mnr P D Hicks wat tans aan die Oepartement

Metal lurgie aan die Univers i te i t van die Witwa

tersrand gesekondeer is om sy MSc-graad te vo l -

t o o i , het die Navorsingstudiebeurs en Goue

Medalje v i r 1983 van die Kamer van Mynwese ont

vang.

Die belangrikheid van individuele navorsers kan

nie genoeg beklemtoon word n ie . Die NIMN beskik

oor 'n aantal voor- en nagraadse beurshouers.

Hul opleiding is noodsaaklik v i r die toekoms

van die I ns t i t uu t . Beurshouers word aan afde-

l ings gekoppcl en word aangemoedig om tydens

hul vakansiss by rffe NIMN te werk. Die presta-

sies van hierdie beurshouers is belonend maar

mnr N Chetty moet spesifiek gemeld word. Hy

het eersteklas slaagpunte en mer ie teser t i f ika te

ontvang v i r albei sy f ina le jaar BSc-vakke,

naamlik Toegepaste Wlskunde I I I en Fisika I I I .

Sy vakansiewerk by die NIMN is van hoogstaande

gehalte en 'n nagraadse beurs is deur die WNNR

aan horn toegeken.

17

C0K1US10H SLOT

1983 «as a stimulating and busy year in which the course for the future was set. He hope that the «any initiatives wil l bear f ru i t and that the NINt will grow and provide the coa-Munity with service at the highest possible levels of excellence.

1983 was 'n stiaulerende en bedrywige jaar waarin die rigting vir die toekoas bepaal is . Ons hoop dat die t a l l e inisiatiewe vrug sal dra en dat die NIHN sal groei en aan die geaeenskap diens van die hoogste aoontlifce vlak van u i t -«untendheid sal verskaf.

HIGHLIGHTS HOOGTEPUNTE

C E R A M I C S , G L A S S A H D P H A S E S T U O I E S

SPIHEL STRUCTURES

It was discovered that certain spinel com

pounds wHh general formula A[B 2]xw can accom

modate appreciable amounts of lithium within

their structures. I t was shown inat durinq

the l ithiation process the [B2]X,, framework of

the spinel structure remained intact. More

over, it was observed that the [B2]Xi, frame

work of the spinel provided a three-dimension

al interst i t ia l space for the diffusion of

lithium through the oxide la t t ice , thus making

spinel compounds attractive candidates for

solid solution electrodes in lithium bat

teries. Of particular interest is the spinel

Li[Mn2]0i, in wMch the lithium ions reside in

part of thf interst i t ia l space defined by the

[Mn2]0i, framework. This compound can accommo

date an additional 0,8 L i + ions in the inter

s t i t ia l space. Moreover, 0,6 Li* ions can be

removed from Li[Wn2]0., without disturbing the

[Mn2]0,, framework, which enhances the capacity

of the LiMh20i, working electrode. These find-

inqs are of significance in the development of

lithium/manganese oxide cells which are cur

rently receiving world-wide attention for the

lithium battery market.

STUOIES OR PHASE DIAGRAMS

An experimental study of the Cd-Ge binary

alloy system at atmospheric pressure has led

to the proposal of an unusual composition-

temperature phase diagram in which a vapour

pha-,e intervenes before melting. Following

this, a theoretical study has been completed

which predicts that similar behaviour should

occur for a surprisingly large number of

binary alloy systems.

K E R A R I E K , 6 l A S E R F A S E-S T U D I E S

SPIRELSTRUKTURE

Daar is ontdek dat sekere spinel verbindinqs

met die algemene samestelling A[B2]X1, aansien-

like hoeveelhede l i t inn in hul strukture kan

opneem. Daar is aangetoon dat die [B 2 ]x H raam-

werk van die spinelstruktuur tydens die opname

van litiumatome onveranderd bly Daar is ook

waargeneem dat die [B 2 |x„ spinelraamwerk drie-

dimensionele ruimtelike diffusie van litium

deur die oksiedrooster moontlik maak, en so-

doende spinelverbindings belowende kandidate

vir vaste oplossing elektrodes in litiumbatte-

rye maak. Die spinel Li[Mn2]ft, is van beson-

dere belang aangesien die litiumatome in tus-

senatoomruimtes van die [Mn2]0k, raamwerk voor-

kom. Hierdie verbinding kan 'n verdere 0,8 L i *

ione in die tussenruimtelike spasie opneem.

Verder kan 0,6 L i * ione uit Li[Mo2]o<, verwyder

word sonder dat die lMn2]0i, raamwerk versteur

word en kan sodoende die vermoê' van die

LifMn2]0t, werkende elektrode verhoog. Boge-

noemde bevindings is betekenisvol vir die ont-

wikkeling van 'iitium-/manqaanoksiedsel1e wat

tans wêreldwv? aandag geniet met die oog op

die mark vir litiumbatterye.

FASEDIAGRAM ORDERSOEKE

'n Eksperimentele studie van die Cd-Ge binêre

legeringsisteem by atmosferiese druk het gelei

tot die postulasie van 'n ongewone komposisie-

temperatuur fasediagram waarin 'n dampfase

voor smelting voorkom. Na aanleiding hiervan

is 'n teoretiese ondersoek voltooi wat voor-

spel dat soortgelyke gedrag vir 'n onverwagte

groot aantal binêre legeringsisteme behoort

voor te kom.

19

POROUS (LASS POREUSE fiLAS

An experimental study of the replacement of Si0 2 in the phase-separable Na2O-820j-SiO2 system by a combination of two oxides was undertaken. Glasses «t.e welted, phase separated by heat treatment, leached and sintered. Preliminary results have ;hown the resulting g.asses and glass ceramics to be porous with specific surface areas up to 300 » 2 / g . Some of then showed alkali and others heat resistance superior to porous Si0 2 glass.

The system Y

2 03-Zr0 2 was chosen for further study by varying the composition ratio and heat treatment. As a result specific surface a>-eas of between 381 and 413 m2/g were achieved, which are the highest surface areas yet prepared by the 61 ass Section of the NIMR. Furthermore an alkali resistance of 2,3 x 10~3 mg/dm2 was measured, which is superior to porous S i0 2 .

SYNTHESIS OF IDEAL POWERS FDR CERAMICS PROCESSUS

Theoretically dense, high quality, single phase ceramics could be prepared if so-called ' ideal ' powders were available. Ideal powders can be defined as being mono-sized, spherical, below one micrometer in diameter, and unagglomerated. The powders used in conventional ceramics processing deviate substantially from the ideal.

A reactor system has been built * . the NIMR to produce ideal or near-ideal powders. This involves the reaction of metal alksxides in solution to form a hydroxide polymer, and conversion of this intermediate polymer to the desired oxide. The reactor system has been designed such that the nucleation and growth steps of this reaction can be tightly controlled.

The reactor system has been used in i t ia l ly to investigate the synthesis of T10 2 . Powders approaching ' i d e a l ' , and far superior to conventional commercial powders, have been prepared. In i t ia l results indicate that the

'n Eksperimentele studie oor die vervanging van Si0 2 deur 'n konbinasie van twee ok sides in die Na 2 0-B 2 0 5 -Si0 2 fase skeibare sisteea is ondemeem. Vr-skillende glassoorte is gesmelt vir fascskeiding, deur hit te behandel, en u i t -geloog en gesinter. Voorlopige resultate toon aan dat hierdie glasse en glaskeramieke poreus is met soortlike oppervlakwaardes so hooq as 300 m 2 /g. Sommige was neer a lka l i - en andere meer hittebestand as poreuse SiO? glas.

Die y 20j-Zr02 sistee» is gekies vir veroere Chioersoeke waartydens samestelling en h i t -tebehandeling gevarieer is. Uaardes vir die soortlike oppervlakke van tussen 381 en 413 mz/g is gevind. Dit is die hoogste scort-1 ike oppervlakke wat noq ooit deur die Glas-sefcsie van die NIMH voorberei is . 'n Alkal i -bestandheid van 2,3 x 10" 3 mg/dm2 is 00k ge-meet, wat hoer is as die van poreuse S i 0 2 .

VERVAARDIGMC VAN IDEALE POEIERS VIR KERAMEK PROSESSERINB

Indien sogenaamde 'ideale' poeiers beskikbaar sou wees sou dit teoreties moontlik wees on digte enkelfase-keramieke van hoé gehalte te berei. Ideale poeiers kan gede'inieer word as sferies, van dieselfde groottc, kleiner as een mifcron in deursnee, en nie verder saamgepak nie. Poeiers wat in konvensionele keramiek-prosesserinq gebruik word, wyk grootliks af van hierdie ideaal.

'n Reaktorsisteem vir die vervaardiqing van poeiers wat ideaal, of na aan ideaal i s , is by die Him gebou. Dit behels die reaksie van metaal-alkoksiede in oplossing om 'n hidrok-siedpolimeer te vorm en die omskakeling van hierdie tussenstappolimeer na die verlangde oksied. Oie reaktorsisteem is sodanig ontwerp dat die kristalkernvorming- en groeistappe van hierdie proses deeglik beheer kan word.

Oie reaktorsisteem is aanvanklik gebruik om die sintese van Ti0 2 te ondersoek. Poeiers wat al hoe nader aan die ideial kom en wat bale meer geskik is as die konvensionele poeiers wat in die handel beskikbaar is, is

20

effect on sintering and final density is dra

matic.

PM DEFICIENCY EFFECTS IN PZT PIEZOELECTRIC CERAMICS

Piezoelectric ceramics based on local raw ma

terials have been developed in this laborato

ry. These include solid solutions of lead

zirconate-lsad titanate (PZT). Work during

the past year included a study of the effect

of PbO vacancy concentrations in the crystal

structure on the resultant piezoelectric and

dielectric properties. PbO may be lost from

the s ructure during sintering, and methods

have been developed to control t ightly the

concentration of PbO vacancies in the struc

ture to desired values. •' e major effect of

the PbO vacancy concentration is seen in the

evolution of the microstructure during sinter

ing. I t has been found that most piezoelectric

and dielectric properties display a maximum

close to the composition with maximum defect

concentration.

E L E C T R O N I C M A T E R I A L S

LIQUID PHASE EPITAXIAL GROWTH OF (HgCd)Te

The f i rst layer of (HqCd)Te h»j been grown

epitaxially on a CdTe single crystal sub

strate. The layer was prepared from a non-

stoicbiometric melt consisting of 19:1:80

Hg:Cd:Te at approximately 500 °C. In order to

equilibrate the melt a source crystal of

*<lo»HCdo,2Te grown in the Institute by solid

state recrystallization was employed.

The resultinq layer was single crystalline and

had a composition of Hg 0, 0 5Cdo,9sTe. This

represents the f i rst local epitaxial qrowth of

(HqCd)Te.

SOLID STATE «CRYSTALLIZED (MgCd)Te

The technique of solid state recrystallization

has been successfully employed in the growth

of Hq 0, f lCd 0,2Te. The material is homogenized.

voorberei. Voorlopige result ate dui daarop

dat die invloed op die sinterproses en finale

digtheid dramaties is .

EFFEK VRN PM-TEKORT IN PZT-PI(50iLEKTRIESE KERAMEKE

Piésoélektriese keramieke uit plaaslike grond-

stowwe is in hierdie laboratorium ontwikkel.

Oit sluit vaste oplossings van loodsirkonaat-

loodtitanaat (PZT) in. Navorsing die afgelope

jaar net 'n ondersoek inqesluit van die effek

van Jie PbO-leemtekonsentrasies in die kr is-

talstruktuur op die qevolglíke piësoéïektr'ne

en dielektriese eienskappe. Die PbO kan tydens

die sinterproses vanuit die struktuur verlore

gaan en deeglike beheermetodes is ontwikkel om

konsentrasie van PbO-leemtes in die strAtuur

na gewenste waardes te verander. Die grootste

effek van die PbO-Itemtekonsentrasie kan waar-

geneem word by die ontwikkeling van die mikro-

struktuur tydens die sinterproses. Daar is

bevind dat die meeste piésoéïektriese en d i -

elekt: _se eienskappe 'n maksimum waarde toon

wat na is aan samestellings met die maksimum

defekkonsentrasie.

E L E K T R O R I E S E H A T E R I A L E

VL0EISTOFFASE EPITMCSIélE GR0EI VAN (HgCd)Te

Die eerste laqie (HgCd)Te is epitaksieel op 'n

CdTe-enkelkristalsubstraat gegroei. Die laqie

is voorberei uit 'n nie-stoïgiometriese smelt

bestaande uit 19:1:80 Hg:Cd:Te by onqeveer

500 °C. Om die smelt in ewewig te bring is 'n

Hg0,gCd0,2Te bronkristai gebruik wat binne die

Instituut deur vastetoestand-herkristalisasie

qegroei is.

Die laqie wat so verkry is , was enkelkristal-

lyn met 'n samestel 1 inq van Hg0,o5Cd0,95Te.

Dit *s die eerste geval van plaaslike epitak-

siële groei van (HqCd)Te.

VASTETOESTANO-HERKRISTALLISEEROE (HgCd)Te

Die vastetoestand-herkristallisasie-teqniek is

suksesvol op die groei van Hg 0 , ,Cd 0 , 2Te toege-

pas. Die materiaal is qehomoqeniseer, qeblus

quenched and then annealed below the solidus

temperature for that composition. The result

ing material has millimetre-size grains and

uniform composition. This material is subse

quently annealed in Hq vapour in order to im

prove stoichicr-etry by removing Kg vacancies.

The material obtained in this May has an n-

type character.

Hil l analyses of the material before and after

the second anneal show it co change from ap

proximately 1 0 1 7 cm"3 p-type character to

3 x 1 0 1 5 cm"3 n-type as a result of the Hg-

vapour anneal. The results of the Hall analy

ses performed in this way are consistent with

the theoretical analysis reported in the 198?

- 1983 Annual Report.

LOW RESISTANCE OHNIC CONTACT MEASUREMENTS

As part of the Division's research into con

tacts on semiconductors, the resistance of

such contacts have to be measured. The tech

niques available for doing this have been

investigated and found to suffer from various

drawbacks. In order to overcome some of these

diff icult ies a concentric ring pattern was

mathematically evaluated and found to offer

significant advantages compared with the

classical rectangular patterns as regards

accuracy and edge effects. The pattern is at

present being evaluated experimentally and is

expected to make a major contribution to the

materials assessment abil i ty in the Division.

M A T E R I A L S C H A R A C T E R I Z A T I O N

THE SURFACE COMPOSITION OF GaAs

The surfaces of GaAs and other semiconductors

require careful cleaning before further proc

essing to make electronic devices. To opti

mize the cleaning processes for GaAs, a know

ledge of the composition and structure of the

oxide layer formed on GaAs is required. Using

X-ray photoelectron spectroscopy ano ion mi-

croprobe mass analysis the presence of Ga 2 0 3 ,

As 2 0j, As 2 0 5 , GaAs03, GaAsC, Ga(0H)3 and As

en toe uitgegloei onder die solidus tsmpera-

tuur vir daardie samestelling. Die materiaal

wat op hierdie wyse berei i s , het millimeter

grootte korrels en eenvormige samestelling.

Hierdie materiaal is daarna uitêgloei in Hg-

damp om die stoTqiometrie te verbeter deur Hg-

leemtes te verwyder. Die materiaal wat so

berei i s , het 'n n-tipe a v d .

Hall-analises van die materiaal voor e na die

tweede uitgloeiing toon dat dit van ongeveer

1 0 1 7 cm"3 p-tipe aard na 3 x 10 1 5 cm"3 n-tipe

verander as gevolg van die Hg-damp uitgloei

ing. Die resultate van hierdie Hall-analises

stem ooreen met die teoretiese analise waaroor

ve--lag gedoen is in die 1982 - 1983 Jaarver-

slag.

LAE MEERSTAND OHHIESE UMTAKHETIKSE

As deel van die Afdeling se navorsinq oor kon-

takt« op halfgeleiers, word die weerstaud van

sodanige kontakte gemeet. Die beskikbare teg-

nieke hiervoor is ondersoek en verskeie te-

kortkominge is gevind. Ten einde sommige van

hierdie probleme te bowe te kom, is 'n konsen-

triese ringpatroon wiskundig evalueer en is

bevind dat dit beduidende voardele bo klas-

sieke reghcekige kontakte het ten opsigte van

akkuraatheid en randeffekte. Die patroon word

tans eksperimenteel evalueer en daar word ver-

wag dat dit 'n belangrike bydrae tot die mate-

riaalkarakteriseringsvermoê' in die Ardeling

sal lewer.

H A T E R I A A L K A R A K T E R I S E -R I NG

DIE 0FPERVLAKSAMESTELLIR6 VAN GaAs

Oie opperviakke van GaAs en ander halfgeleiers

vereis versiqtiqe suiwering voor verdere pro-

sessering vir die maak van elektroniese toe-

ste l lc . Om 'lie suiweringsproses vir GaAs te

optimiseer, is kennfs van die samestelling en

struktuur van die oksiedlaag op GaAs nodig.

Met brhulp van X-straalfotoéïektronspektros-

kopie en ioonmikrosonde-massa-analise, is die

teenwoordiqheid var. GaíOa, AS2O3, AS2O5,

22

in the oxide layer «as established. Ga 20 3 and As 20 3 occurred st the GaAs-oxide interface and A<^05 and GaAsOi, at the oxide-air interface. G-(0H)3 and As occurred throughout the layer. It is envisaged that this information will aid in improving the cleaning process.

COMPUTER MODEL! I K OF THE «WHITE FUKMCE

The graphite furnace is used in atonic absorption measurements for converting a sample into a cloud of free atoms capable of absorbing a proportion of a l igrt beam passing through the cloud. The furnace consists of a hollow graphite cylinder about 28 mm long with internal and external diameters of 6 and 8 mm respect ively. In use. this tube reaches a temperature of 2 000 K in less than one second. Detailed knowledge of t .» dynamic temperature distribution across the tube lenqth as well as the gas temperature in the furnace it required for quantitative calculations of chemical interference and atomization mechanises. Considerable success has recently been achieved in calculating these temperature distribution parameters by numerical methods based on a physical model of the graphite tube and the gas contained within i t . This development is an important step forward in the quantitative understanding of the mechanisms involved in qraphite furnace atomization. This understanding should lead to a minim;zinq of chemical interferences and thus to a ii-gher accuracy of analysis.

M E T A L S

HAftDEMBILITV EFFECTS OF CARD IDE-FORM RS ELEMENTS IN LOM-ALLOY STEELS

As part of the development proqramme for Mo-free medium carbon low alloy steels, the addition of rarbide-forming elements was studied, v i z . , V, Ir, Ti and Nb. It has been shown that their influence on hardenability is cr i t ica l ly dependent on the steel k i l l ing additions, i.e. the additions of Si , Al and T i , used to remove oxygen and nitrogen from the melt. The results

G*AsG3, GaAsOu, 6a(0K)3 en As in die ofcsieo-laag vasqestel. Ga?03 en As 20 3 ko» in die GaAs-oksiedtussenvlak voc., en As20j en GaAsO, in die oksied-luq tussenvlak. Ga(0H)3 en As kom dwarsdeur die laag voor. Oit word verwjag dat hierdie inligting var nut sal wees by die verbtitering van die suiweringsproses.

REKENANWOOEL WW DIE OUFIETOtMD

Ois grafietoond w»rd in itoomabsorpsiewetings gebruik vir die omsetting van "n monster in 'n wolk van vrye atome wat in staat is o» 'n ge-deelte van die ligstraal wat deur die wolk gaan te absorbeer. Die oond bestaan uit 'n hoi grafietsil inder, ongeveer 28 ma lank en met binne- en buite-deursnee van 6 en 8 mm respektiewelik. Tydens gebruik bereik hierdie bu.s 'n temperatuur van 2 000 K in minder as een sekonde. Grondige kennis van die dinaniese temperatuurverspreiding oor die lengte van die buis asook dip qastemperatuur in die oond is nodig vir kwantitatiewe berefcenings van che-miese interferonsie- en atomiserinasmeganis-mes. Deur middel van numeriese metodes geba-seer op 'n fisiese model van die grafietbuis en die gas diarin, is aansienlike sukses on-langs in die berekening van die parameters vir hierdie temperatuurverspreidings behaal.

ierdie ontwikkeling is 'n belangrik» voor-waartse stap in die kwantitatiewe begrip van die meganismes betrokke by grafietoond atomi-sering. Insig hierin behoort te lei tot die beperking van chemiese interferensies tot 'n minimum en 'n gevol^like groter mate van bepa-lingsakkuraatheid.

M E T A L E

DIE EFFEK VAN KAtBIEDVOfWENDE ELEMENTE OP DIE VEIMAftOBAARHEIO VAN LAE-LEGERING STALE

Die toevoeging van karbiedvormende elemente, V, Ir, Ti en Nb, is as deel van die ontwikke-lingsprogram oo' Mo-vrye mediumkoolstof-'ae-leqeringstale bestudeer. Daar is gevind dat die elemente se invioed op die verhardbaarhrid krittes afhanklik is van die staaltemming-byvoeqings, dit is byvoeqinqs van S i , Al en Ti wat opbruik word om suurstof en stikstof uit

show that V in steel killed with Al and Ti,

and Ir i"- steel killed with Si, can produce

significant enhancement of hardenability. The

new data have led to a reassessment of the

possible synergistic effect between B and V.

SUSPENSION CASTING OF WHITE CAST IRONS

White cast irons represent an important class

of abrasion-resistant alloys, but characteris

tically they suffer from limited impact re

sistance. Using conventional casting technol

ogies, the microstructure for hypo-eutectic

alloys consists of non-random dendritic orien

tations giving anisotropic mechanical behav

iour. The present work has applied suspension

casting (microchillfng) to this class of

alloys for the first time. The process con

sists of adding metallic powders to the molten

metal during pouring. The results indicate

that it is possible to produce a refined ran

dom orientation of dendrites which now exhib

its isotropic properties.

FERRITIC NITROCARBURIZING

Ferritic nitrocarburizing involves the addi

tion of nitrogen and carbon to the surface of

steel parts at temperatures below 590 "C.

Under the correct conditions <i surface layer,

typically 5 - 2 0 urn, composed of iron carbo-

nitrides is produced. This surface layer is

responsible for significant improvements in

seizure resistance and is applied to a number

of components in automotive engines. In the

current research, a simple new method for the

structural characterization of the surface

layer structures has been developed. Using

this method of analysis ft has been possible

to control production of ' series of different

structures, which are being evaluated under

sliding wear conditions. This technique should

bt of significant vjlue to the industrial

users of the procer, •,.

MECHANICAL PROPERTIES OF 3CR12

The locally developed corrosion reiistant

dual-phase steel 3CR12 is being applied in

die smelt te verwyder. Lie resultate toon 'n

aansienlike yerbetering in die verhardbaarheid

van V in staal wat met Al en Ti get em is, as-

ook die van Zr in staal wat met Si getem is.

Hierdie nuwe data net gelei tot 'n herevalue-

ring van die moontlike saamgestelde effek wat

deur B en V veroorsaak word.

SUSPENSIE6IETING VAN HIT GIETYSTERS

Witgietysters verteenwoordig 'n belanqrike

tipe skuurbestande legering, maar toon kenmer-

kend beperkte slagweerstand. Met gewone giet-

praktyke bestaan die mikrostruktuur van hipo-

eutektiese legerings uit nie-willekeurig» den-

dritiese oriëntasies wat anisotropiese mega-

niese gedrag toon. Huidiqe werk pas vir die

eerste keer suspensiegieting (mikro-verkil-

ling) op hierdie tipe legerings toe. Die pro

ses behels die byvoeying van metaalpoeiers by

die gesmeite metaal tydens gieting. Resultate

toon dat dit moontlik is om 'n verfynde wille-

keurige dendritiese orie'ntasie wat isotropiese

eienskappe toon, te produseer.

FERRITIESE NITRIED0PK0LIN6

Ferritiese nitriedopkoling behels die toevoe-

ging van stikstof en koolstof tot die opppr-

vlakke van staalonderdele by temperature laer

as 590 °C. Onder gunstige toestande word 'n

oppervlaklaaq, tipies 5 - 2 0 wm, bestaande uit

yster-koolnitriede geproduseer. Hierdie opper-

vlaklaag is verantwoordelik vir verbeterings

in vasbrandbestandheid en is op 'n aantal on-

derdele in selfbewegende masjiene toegepas.

'n Eenvoudige nuwe metode vir strukturele

karakterisering van die oppervlaklaag-struk-

ture is deur die huidige navorsing ontwikkel.

Oeur hierdie ontledingsmetode te gebruik, kan

produksie van 'n reeks verskillende strukture

wat tans onder skuurslytasle-toestande evalu-

eer word, beheer word. Hierdie tegniek behoort

betekenisvolle waarde vir nywerheidsgebruikers

van die proses te hê.

ME6ANIESE EIENSKAPPE VAN 3CR12

Die plaasllk ontwlkkelde korroslebestande

dubbelfase staal 3C"12 word in 'n breë reeks

24

wide ranging applications in industry. The detailed study of the continuous yield and three-stage work-hardening behaviour has been extended to follow the dislocatior behaviour during each of these stages. This investigation has provided valuable information on the effects of transformation-strain induced dislocations in deformation of the ferritic phase. Further tests on low-cycle fatigue behaviour has revealed differences in behaviour for alloys containing different martensite volume fractions, and useful total strain life curves were generated.

toepassings in die nywerheid aangewend. Die grondige ondersoek na die kontinue swigting en driestadium werkverhardingsgedrag • uitgebrei om die ontwrigtingsgedrag gedurend. .nerdie stadiums te volg. Hierdie ondersoek het w;»r-devolle inligting oor dip nvloed van trans-formasievervorminq-geinduseerde ontwrigtings op deformasie van die ferrietfase gelewer. Verdere lae-siklus vermoeidheidstoetse het verskille in die gedrag van legerings met ver-skillenle volunefr?<sies martensiet aangetoon, en bruikbare totale vervorming teen lewens-duurtekronmes is verkry.

25

RESEARCH ACTIVITIES NAVORSINGBEDRYWIGHEDE

The aim of the Division is to investigate the structure, properties and processing of a wide range of inorganic materials. The materials studied are primarily ceramics, glasses and single crystals, thus covering crystalline and amorphous structures.

Major emphasis is placed on understanding, at a fundamental level, materials processing in terms of phase behaviour, and on the relation of properties of materials to processing parameters. Much of the work related to high temperature and pressure, is associated w.th materials of lo'--t1 importance.

The Division comprises five sections:

• Ceramic Processing • Glass Development • Phase Studies • Properties of Materials • Electrochemistry.

K E R A N I E K , 6 L A S EN F A S E -S T U D I E S

S Hart Head of Division / Afdelingshoof

Die doelwit van die Afdellng Is om die struk-tuur, eienskappe en verwerklng van 'n wye reeks anorganlese materiale te ondersoek. Die materiale wat bestudeer word, is hoofsaaklik keramieke, glassoorte en enkelkristalle, en sluit dus ook kristallyne en amorfe strukture in.

Groot klem word geplaas op die fundamentele begrip van materiaalprosessering In terme van fasegedrag en op die verhouding van eienskappe van materiale tot veranderllkes in die verwer-king daarvan. Bale van die werk met betrek-klng tot hoë temperatuur en druk hou verband met materiale wat plaaslik van belang 1s.

Die Afdeling bestaan u1t vyf seksles:

• Keramlekprosessering • filasontwikkellng • Fasestudies • Eienskappe van Materiale • Elektrochemle,

?6

The last two sections were created during the

current year.

Considerable emphasis is also la id on contract

work for industr ia l sponsors.

C E R A M I C P R O C E S S I N G

The aim of th is Section is the development of

special ized ceramic technology. Th's includes

a l l aspects of powder preparation, compaction,

s in ter ing and the f ina l characterization of

the ceramic body.

There are four projects

• Ceramic Processing

• Alumina Ceramics

• Two sponsored projects.

CERAMIC PROCESSING

Ac t i v i t i es on th is project include research

and development in the f i e l d of ceramic pro

cessing, with special emphasis on processing-

property-performance re lat ions.

Research Activities

During the past year a reactor system has been

designed and bu i l t for the chemical synthesis

of ceramic powders from solut ion, under condi

t ions whereby the nudeation and growth steps

may be t i g h t l y contro l led. The major motiva

t ion is to determine whether ' i dea l ' powders

(of ideal s ize, shape and size d is t r ibu t ion )

can be prepared reproducibly. In i n i t i a l work

the T i0 2 system is being studied, and near-

ideal powders hive been synthesized. These

powders show s iqn i f i can t l y improved sinter inq

behaviour over conventional powders.

The use of ceramics as engineering materials

has t r ad i t i ona l l y been l imited by b r i t t l eness ,

or lack of toughness. B r i t t l e fracture is a

common mode of fa i lu re in ceramics. In recent

years a class of ceramics known as transforma

t ion toughened zirconia (TTZ) has been devel

oped. I t has been shown that by the control led

Laasqenoemde twee seksies net qedurende die

jaar to t stand gekom.

Daar word ook besondere klem gelê op kontrak-

werk v i r borge u i t d ie nywerheidsektor.

K E R A N I E K P R O S E S S E R I N G

Hierdie Seksie s te l horn ten doel om qespesia-

liseerde keramiektegnologie te ontwikkel. Dit

si u i t in a l l e aspekte van poeiervoorbereiding,

-saampakking, s in ter ing en die f ina le karakte-

r iser ing van die keramiekvoorwerp.

Oaar is v ier projekte

• Keramiekprosessering

• Alumina Keramieke

- Twee geborgde pro jekte.

KERAMEKPROSESSERING

Die keramiekprosesseringsaktiwiteite s l u i t in

navorsing en ontwikkel i ig op die gebied van

keramiekprosessering met besondere klem op die

prosessering-eienskap-werkverrigting verwant-

skappe.

Navorsingsaktiwiteite

'n Reaktorsisteem is die afgelope jaar ontwerp

en gebou v i r die chemiese sintese van kera-

miekpoeiers vanuit oplossino onder toestande

waar die kernvorming en groeistappe deeglik

beheer kan word. Die hoofdoel was om te be-

paal of ' idea le ' poeiers (met ideale ko r re l -

qrootte, vorm en qrootteverspreiding) herpro-

duseerbaar vervaardiq kan word. Tydens die

aanvanklike werk is die Ti0 2-sisteem ondersoek

en poeiers ná aan ideale poeiers is ges in te t i -

seer. In vergelyking met konvensionele poeiers

toon hierdie poeiers daadwerklike verbetering

in sintereienskappe.

Die gebruik van keramieke as ingenieursmateri-

aal was in die verlede beperk as gevolq van

die inherente brosheid of gebrek aan taaiheid.

Keramieke faal dikwels as gevolg van bros-

breuke. Die afgelope aantal jare is 'n groep

keramieke ontwikkel wat as transformasie-ver-

sterkte sirkonia (TTZ) bekend staan. Daar is

transformation of the tetragonal to the mono-clinic phase the strength of zirconia can be improved considerably. Correct preparation of the microstructure is v i ta l ly important. I f correctly prepared, TTZ can outperform metals in a rapidly increasing number of application;,.

The HIMR is presently involved in the development of TTZ, paying particular attention to the use of local Zr0 2 (baddeleyite). The processing of a range of composite.ns of TTZ has been investigated. The results show that control of composition and processing conditions allows one to optimize either hardness or toughness of the ceramic.

Development work on piezoelectric ceramics based on lead zirconate - lead titanate solid solutions continued during the past year. A short study was made of the effect of higher Si0 2 impurity content in the Zr02 raw material on the properties of PZT-4 type material. An intensive study has been made of the sources of variabil i ty in the properties of PZT-4 ceramics. In particular, the effect of the PbO defect concentration on piezoelectric properties has been investigated.

Nasicon is a rapid sodium ion conductor used in polycrystalline ceramic form for application in high-energy density batteries. The effect of small systematic changes in stoi -chiometry within the Na[ + x Zr 2 Si x P 3 _ x Oi 2

solid solution corresponding to a 0-1,7 mass % excess of Na 20, a 0-5,4 mass % deficit in Zr0 2 , and a variation of x from 1,85 to 2,3 has been investigated. The changes had a significant effect or -e densiflcation kinetics and the amount of second phase Zr02 present aft»r sintering. Sodium ion conductivity measurements, using complex plane impedance analysis, indicate only small changes with respect to results reported in the l i terature. Extrapolation techniques and mathematical modellinq of the complex plane impedance results, in comparison with conductivity values obtained from sodium-sodium cell tests.

28

aangetoon dat indien die faseoorqang vanaf die tetragonale fase na die monokliniese fase deeglik beheer kan word, die sterkte van sir -konia aansienlik verbeter kan word. Korrekte bereidinq van die mikrostruktuur is van die uiterste belang. Indien op die reqte wyse berei, is die werkverrigting van TTZ in 'n steeds toenemende aantal toepassings baie beter as die van met ale.

Die NIMN is tans betrokke by die ontwikkeling van TTZ en besondere aandaq word qeskenk aan die gebruik van plaaslike Zr0 2 (baddeleyiet). Die prosessering van 'n reeks TTZ-samestel-linqs is ondersoek. Die resultate dui daarop dat of optimale hardheid of optimale taaiheid van die keramiek deur beheer van die samestel-linq en prosessering verkry kan word.

Die ontwikkelingswerk op die piësoëlektriese keramieke wat op loodsirkonaat-loodtitanaat vaste oplossinq gebaseer is , is die afgelope jaar voortgesit. 'n Kort studie is uitqevoer op die effek wat hoër Si02-onsuiwerhede in Zr02-grondstowwe op die eienskappe van PZT-4 tipe materiaal het. 'n Intensiewe studie is gedoen om die oorsake van die veranderlikheid in die eienskappe van PZT-4 keramieke vas te ste l . In besonder is die effek van die PbO-defek konsentrasie op die piësoëlektriese eienskappe ondersoek.

Nasicon is 'n vinnige natrium-ioongeleier wat as 'n polikristallyne keramiek in hoë'-energie-digtheid-batterye aangewend word. Die effek van klein sistematiese verande-rings in die sto'fgiometrie binne die N a i + x Z r 2 S i x P 3 . x O I 2 vaste oplossing is ondersoek. Samestellingsveranderings van 0-1,7 massa X oormaat Na20, 'n 0-5,4 massa X tekort aan ZrOi, en 'n veranderinq in x vanaf 1,85 tot 2,3 is ondersoek. Die veranderinqs het 'n betekenisvolle effek gehad op die ver-diqtinqskinetika en hoeveelheid tweede fase Zr02 wat na sintering teenwoordiq is. D4e metinqs van natrium-ioon geleidingsvermoé' deur middel van komplekse vlak impedansie-analises het slegs in 'n qerinqe mate afqewyk van resultate wat in die Hteratuur vermeld is. Resultate verkry van ekstrapolasieteanleke en die wiskundige modellerinq van komplekse vlak

indicate that differences in Na+ ion conduc

t i v i t y are obtained using d i f ferent methods

of analysis. A study of the methods of ob

ta in ing conductivi ty data is therefore i n

dicated.

With regard to the characterization of ceram

ics the NIMR, during the past year, has been

extending the range of tests available for

routine measurement of mechanical properties

of the engineering ceramics. Hardness and

fracture toughness methods have been estab

l ished, and the f a c i l i t i e s fo r 4-point f l exur -

al strength measurement are being completed.

The major area in which engineering ceramics

are currently being used in South Afr ica is in

the conveying of sol id mater ia ls, par t i cu la r ly

pneumatic conveying. A r ig has therefore been

b u i l t and is now beinq commissioned, to study

the performance of ceramics in an erosive wear

s i tuat ion caused by par t i c le impact, and to

study the mechanisms of th is wear.

ALUMINA CERAMICS

The aim of th is project is to study the pro

cessing and properties of alumina ceramics,

with special emphasis on the high pur i ty

single phase aluminas.

Research Activities

Work on the effect of the Mgd dopant on the

s in te r ing , microstructure a-ïd properties of

high pur i ty alumina has continued. I t has

been shown that as long as the PgO dopant is

par t i cu la r ly well d is t r ibu ted , only a small

amount of MgO is necessary to aid densif ica-

t i o n . A mass of 0.03X ras been shown to be

optimum which Is substart) 11y lower than the

0,3 mass t norma'ly quoted in the l i t e ra tu re .

A loca l ly processed high pur i ty alumina has

also been evaluated. Oirect comparison of the

s inter inq behaviour of this material has been

made with that of Alcoa A17. The local mate

r i a l has also been further processed, primarf-

'mpedansie in verqelyking net waardes van ge-

leidingsvermoé wat van natrium-natriumsel

toetse verkry i s , dui daarop dat die geDruik

van verski l lende analisemetodes verski l lende

waardes van Na*-ioon geleidingsvermoë' gee. 'n

Studie van die metodes waarmee hierdie g e l e i -

dingsvermoë-data verkry kan >>ord, blyk dus

nodig te wees.

Ten opsigte van die karakter iser ing van kera-

mieke het die NIMH die af gel ope jaar die reeks

toetse v i r die roetinebepaling van die mega-

niese eienskappe van ingenieurskeramieke u i t -

qebrei. Die hardheid en breuktaaiheid is be-

paal en f a s i l i t e i t e v i r die 4-punt buigspan-

ningsmeting nader vo l too i ing .

Ingenieurskeramieke word tans in Suid-Afrika

veral benut in die vervoer van vaste mate-

r i a l e , <^\ in die besonder in pneumatiese ver

voer. 'n Toestel is dus opgerig en word tans

in gebruik geneem om ondersoek in te s te l na

die gedrag van keramieke in 'n e ros ie -s ly ta -

sie s i tuasie wat deur part ikelbotsings veroor-

saak i s , asook na die meganismes van hierdie

s l y tas ie .

ALUMMA-KERAMIEKE

Die doel van hierdie projek is om die proses-

raring en eienskappe van alumina-keramieke te

ondersoek, met besondere klem op enkelfase

aluminas van hoë suiwerheid.


Ondersoeke na die effek van die MgO-doteermiri

del op die s in te r ing , mikrostruktuur en eien

skappe van hoë suiwerheid alumina is voortge-

s i t . Daar het geblyk dat indien die MgO-

doteermiddel baie deeglik versprei is slegs 'n

k le in hoeveelheld MgO nodig is om verdigt ing

aan te help, 'n Massa van 0,03* blyk 'n o p t i -

male byvoeging te wees en is aansienlik laer

as die 0,3 massa X wat gewoonlik in die l i t e -

ratuur gemeld word.

'n Hoé' suiwerheid alumina wat plaasl ik ver-

vaardlg i s , 1s ei i lueer. Die sintergedrag van

hierdie materi,- : s direk met die van Alcoa

A17 vergelyk. ' ,,'laaslike materiaal is

verder geprosesseer, hoofsaaklik om die par t f -

29

ly to a l te ' the particle siie and sue d is t r i bution, and the resulting mrterials compared with the so-called reactive aluminas such as Alcoa A16-SG and Reynolds RC-HP-DBN. The results indicate that it is feasible to use the local alumina for the fabrication of high strength, high purity (>99,5X) A1 2 0 3 bodies by solid state sintering.

G L A S S D E V E L O P M E N T

The aim of this Section is to develop new glasses and glass ceramics. Phase separation and sol gel methods are used. Novel materials such as porous glasses and unusual optical f i l te rs *re stLdied.

There are two projects:

• Glass development • A sponsored project.

GLASS DEVELOPMENT

Work is directed towards phase separation in alkali boroxide systems to achieve high surface areas of interconnected pores and good chemical and thermal resistance. The sol gel methods are being evaluated for low temperature glass production.

Research Activities

In continuation of previous work the glass-fjrminq regions for 5-20 mass X Na 20, 30-90 mass X B 20 3 and 5-55 mass X of a third oxide X (X « an oxide of A l , Ce, Ga, Hf, La, Nd, Sc, Ta, Th, T1, Y and Zr) were established. For each system 20 to 30 melts were undertaken. Porous materials were obtained after heat treatment and leaching (Fig. 1 ) .

Sintering of these leached materials resulted In a better understanding of the transformation processes. A1 2 0, , Ga20j and Sc203-based porous materials are total ly developed, while measurements of the physical properties of the others are in progress. In a further experiment the replacement of B 2 0 3 by P 2 0 5 in the Na 20-B 20 3-S10 2 system was successful.

kelgrootte en grootteverspreiding te wysig, en die «...icriale wat so verkry i s , is vergelyk met die sogenaande reaktiewe aluminas, byvoor-beeld Alcoa AI6-SG en Reynolds RC-HP-DBM. Die resultate toon dat plaaslike alumina vir die vervaardiging van hoë-sterkte hoé-suiwerheid (>99,5X) Al203-voorwerpe in vastetoestand sintering gebruik kan word.

G L A S O N T H I K K E L I D G

Die doe 1 wit Man hierdie Seksie is om nuwe glas en glaskeramieke te ontwikkel. Faseskeiding en sol-gel metodes word gebruik. Nuwe materi-ale soos poreuse glassoorte en ongewone op-tiese f i l te rs word ondersoek.

Daar is twee projekte:

• Glasontwikkelinq • 'n Geborgde projek.

GLASONTHIKKELINE

Studies is gerig op faseskeiding in a lka l i -boron-oksiedsisteme om groot oppervlakareas met verbin<?ende porieé asook qoeie chemlese en termiese weerstand te verkry. Die sol-gel met ode w.ird evalueer vir die vervaardiginq van glas by lae temperature.

NavorsingsaktiwHeite

Tydens die voortsetting van vorige werk is die glasvormende gebiede vir die 5-20 massa X Na 20, 30-90 massa X 8 2 0 3 en S-55 massa X van •n derde oksied X (X » oksied van Al, Ce, Ga, Hf, La, Nd, Sc, Ta, Th, T i , Y en Zr) vasge-s te l . Vir elke sisteem is 20 tot 30 smelte onderneem. Poreuse materiale is na hittebe-handeling en 'n uitloglng verkry (Fig. 1) .

'n Beter begrip van die omskakelingsproses is verkry deur sintering van hierdie geloogde materiale. Studies op die poreuse materlale verkry ult A1 203, Ga203 en Sc 20 3 is voltooi en metlngs van die fisiese elenskappe van die ander word voortqesit. In 'n verdere eksperi-ment was die ondersoek na die vervanglng van B 2 0 3 deur P20s in die Na 20-B 20 3-Si0 2 sisteem suksesvol.

30

Together with the single oxide replacements,

binary oxide replacement for SÍO2 was carried

out. In the system Na 20-B 20 3-Zr02-Y2 03 t n * r e "

sulting Zr02-Y203-rich material showed a sur

face area of interconnected pores of 410 m 2/g.

A series of heat treatment experiments was

carried out to achieve a Si0 2 -rich glass doped

with Nd203 from Na20-B203-Si02-Nd203 doped

base glass (Fig. 2 ) . Leaching (Fig. 3) and

sintering was iiso successfully completed.

Die vervanqinq van Si0 2 deur sowel enkel as

binêre oksiede is uitgevoer. In die Na20-

B203-Zr02-Y203 sisteem het die ZrO^Ôj-ryke

materiaal waardes van 410 m2/g vir die spesi-

fieke oppervlakareas van tussenverbinde porieë

getoon. "n Reeks hittebehandelingeksperimente

om vanuit 'n Na 20-B 20 3-Si0 2-Nd 203 glas 'n

Si0 2-ryke glas wat met Nd 20 3 gedoteer is te

berei , (Fig. 2) asook loging (Fig. 3) en sin

tering daarvan, is suksesvol uitgevoer.

FIGURE/FIGUUR 1

Porous monodinic B-Ga203 prepared from Na20-B203-Ga203 glass by phase separation and

leaching.

Poreuse monokliniese B-Ga203 wat berei is van Na 20-B 20 3-Ga 20 3 glasse deur faseskeiding en

loging.

SB

Si

TEMHR4TURE C O TEMWMTUWH'C)

FIG 8 WEIGHT LOSS VS TEMPERATURE

FIG 8 GEWIGVERLIES VS TEMPERATUUR

FIGURE/FIGUUR 2

Secondary electron image of a phase separated Nd 20 3 doped sodium borosilicate glass. The

etched surface reveals two phases formed as a result of heat treatment.

Sekondêre elektronbeeld van 'n Nd203-doteerde natriumboraatqlas wat deur faseskeiding berei is . Die geëtste oppervlakte toon twee fases

wat as qevolq van die hitte-behandeling gevorm het.

FIGURE/FIGUUR 3

Effect of heat treatment on leaching. Weight loss under constant leaching conditions for

heat treatment of 1,6 and 24 hours at temperatures of 500, 550, 600 and 700 C

Effek van hittebehandeling op loging. Massa-verlies onder konstante loogtoestande vir

hittebehandeling van 1,6 en 24 uur by temperature van 500, 550, 600 en 700"C

A part of the project was dedicated to the

development of machinable glass ceramics, pre

pared by nucleation and crystallization of

glass melts. Local development of this mater

i a l , based on fluorobiotlte mica, is nearing

completion. DuMnq the reported period a num

ber of physical properties were measured.

'n Onderafdellng van hierdie projek is gewy

a an die ontwikkeling van masjineerbare qlas-

keramieke wat deur kernvormlng en kr ls ta l l isa -

s1e van qesmelte glas voorberel word. Plaas-

Hke ontwikkeling van hierdie materiaal wat op

fluorobiotiet mika gebaseer is , is bykans vol-

tooi. Verskeie flsiese eienskappe is geduren-

de die afgelope vers lag jaar bepaal.

31

Sol-9*1 glass preparation uses a method which

allows the production of special glasses of

high homogeneity at lower than conventional

temperatures.

The work carried out concerned the preparation

of solids containing glass-forming and glass-

modifying oxides of Al , As, Ca, Co, Cu, Fe,

Na. Sb, S i . Ti and Zn.

After solidification the gelatinasation pro

cess was successfully carried out with most of

the single oxides and with combined composi

tions, provided the medium had a low pH con

tent.

work is continuing with the view of determin

ing the effect of variables such as pH, time,

temperature and concentration.

P H A S E S T U D I E S

The aim of this Section is to study the phase

behaviour of materials over a wide range of

temperature and pressure. Studies include

phase transformations, phase stabil i ty regions

and crystal structure determinations.

There are two projects:

• Phase studies

• A sponsored project.

PHASE STUDIES

Differential thermal analysis and related

methods are used to determine phase boundaries

and phase stabi l i ty regions of materials.

X-ray diffraction methods are used to deter

mine the structure of new phases at high and

low temperatures and techniques are being

established to study structure at high press

ure.

Research Activities

An experimental study on the Cd-Ge binary

alloy system at atmospheric pressure has led

to the proposal of an unusual composition-

temperature phase diagram In which a vapour

Die sol-gel glasbereidingsproses maak die pro-

duksie van spesiale glasse met hoe homogeni-

teitseienskappe moontlik by temperature laer

as die gebruiklike.

Die stjdies wat uitgevoer i s , net die b*rei -

ding behels van vaste stowwe wat glasvormende

en glasveranderende oksiede van A l , As, Ca,

Co, Cu, Fe. Na, Sb, S i , Ti en Zn bevat.

Ha stolling kon die gelatinisasieproses suk-

sesvol op die meeste ennel-oksiede, asook op

die gekombineerde samestellings uitgevoer word

as die pH in die medium laag was.

Studies om die effekte van veranderlikes soos

pH, tyd, temperatuur en konsentrasie vas te

stel word voortgesit.

F A S E S T U D I E S

Die doel van hierdie Seksie is OM die fasege-

drag van materiale oor 'n wye gebied van tem

peratuur en druk te bestudeer. Studies sluit

in die bepaling van fase-oorgange, fasestabi-

liteitsgebiede en die bepaling van k r is ta l -

strukture.

Daar is twee projekte:

• Fasestudies

• 'n Geborgde projek.

FASESTUDIES

Differenslele termiese analise en verwante

metodes word aangewend om die fasegrense en

fasestabiliteltsqebiede van materiale te be-

paal. X-straaldlffraksie metodes word aange

wend om die struktuur van nuwe fases by hoë en

lae temperature te bepaal en tegnleke word ge-

vestlg om strukture onder hoé' druk te bestu

deer.


'n Eksperimentele studle van die Cd-Ge binêre

legerfngsfsteem by atmosferlese druk net aan-

leldlng geqee tot i\i voorstel vir 'n ongc*one

samestelllng-temperatuur fasedlagram waarin 'n

32

phase intervenes before melting. Following

this, a theoretical study has been completed

which predicts that similar behaviour should

occur for a surprisingly large number of

binary alloy systems.

First attempts to calculate ana predict compo-

sition-pressure-tempenture phase diagrams of

binary alloy systems from thermochemical data

appear promising.

The instrumentation of the high-pressure dif

ferential thermal analysis (DTA) fac i l i ty has

been improved. A microcomputer measurement

station has been added to control DTA data

acquisition and manipulation. Pressure meas

urement has been automated by the introduction

of a load ce l l . A dedicated microcomputer-

controlled power supply has been designed and

built locally to provide greater f l ex ib i l i t y

of the DTA temperature programs.

Current activities include

• a study of the pressure-temperature phase

diagram of the compound In2S3

• a study of the calculation of composition-

pressure-teirperature phase diaqrams of

binary alloy systems

• a study of ti.e potential of the load cell

in the hiqh-pressure DTA fac i l i ty to pro

vide an additional technique for detectinq

phase transitions through small pressure

anomalies.

A new apparatus employing the diamond-anvil

technique is being constructed for X-ray dif

fraction studies of powdered crystalline mate

rials under high pressures (~10 GPa). An im

portant design feature is the introduction of

simplified pressure cells which can be mounted

interchangeably within a sinqle compressing

mechanism. After the application of pressure

to a sample confined between the diamond

anvils of a ce l l , this small cell may be re

moved from the compression device and readily

supported on a goniometer. The cell pressure-

plates and diamond seats are slotted to permit

the detection of X-rays diffracted by the sam-

dampfase voor smeltinq voorkom. 'n Teoretiese

studie is hiema voltooi wat daarop dui dat

soortgelyke gedrag by 'n verrassend groot aan-

tal binêre legeringsisteme behoort voor te

kom.

Eerste pogings on die samestelling-druk-tem-

peratuur fasediagramme van binêre legering

sisteme uit termoci.emiese data te bereken en

te voorspel lyk belowend.

Die instrumentasie van die f a s i l i t e i t vir hoë-

druk differensiële termiese analise (OTA) is

verbeter. 'n Mikrorekenaar-metingsapparaat is

bygevoeg om die DTA-apparaat te beheer en die

data in te win en te verwerk. Drukmetings

word nou outomaties deur die gebruik van 'n

las-sel gedoen. 'n Toegewysde mikrorekenaar-

beheerde kraqbron is piaasiik ontwerp en qebou

om groter veelsydigheid aan die DTA-tempera-

tuurprogramme te verleen.

Huidige aktiwiteite sluit in

• 'n studie van die druk-temperatuur fasedia-

gram van die verbinding In2S3

'n studie van die berekening van samestel-

ling-druk-temperatuur fasediagramme van

binêre leqeringsisteme

'n ondersoek na die potensiaal van die ge

bruik van die las-sel in die hoëdruk DTA-

fas i l i t e i t as 'n verdere tegniek om fase-

oorgange deur klein drukafwykings te be-

speur.

'n Nuwe apparaat wat van die diamant hoe'druk-

sei-tegniek gebruik maak, word gebou vir

X-straaldiffraksiestudies van poeier van

kristallyne materiale onder hoe drukke

(~10 GPa). 'n Belangrike nuwe wysiqing aan

die ontwerp is die gebruik van eenvoudige las-

sel le wat binne 'n enkele saampersbaarheids-

meganlsme ultruilbaar gemonteer kan word.

Nartat druk toeqepas 1s op 'n monster tussen

die twee diamante kan hlerdie klein sel let j ie

van die saampersbaarheidsmeqanisme verwyder

word en met gemak op 'n goniometer rus. Groewe

In die drukplate en diamantmontering 1aat

waarneminq toe van gedlffrakteerde X-strale

pie through large angles (up to 85 ° ) , thereby

recording a maximal amount of structural in

formation. Use of this modular design Mill

fac i l i ta te the later development of cells for

high pressure studies at elevated tempera

tures .

The determination of experimental pressures

wil l be performed by the standard method of

recording tne fluorescence spectrum of a ruby

crystal l i te (A1 20 3 + 0,5* Cr) which is includ

ed with the powder. Equipment has been con-

missioned consisting of a helium-cadmium laser

and a computer-controlled spectrometer. This

is respectively for excitation of the fluores

cent radiation and observation of the spectral

shifts induced by applied pressures.

P R O P E R T I E S OF M A T E R I A L S

The aims of the Section are to establish a va

r iety of methods to measure relevant proper

ties of materials being developed in the Divi

sion and to conduct fundamental studies on the

equation of state.

There are three projects:

• Properties of materials

• Two sponsored projects.

PROPERTIES OF MATERIALS

At present the work relates in particular to

the measurement of mechanical and thermal pro

perties of matter such as elastic moduli,

shear strengths and thermal conductivity.

Rese.-rch Activities

Elastic moduli are determined from the veloci

ty of ultrasonic waves passinq throuqh a sam

ple. This method has been estabMshed for a

nutiter of years and can be used under press

ures of up to 2 GPa. In the past year It has

been applied to a variety of single crystals,

glasses and glass ceramics, such as CoF; and

te l lu r i te glass. The Interesting zero thermal

vanaf die monster tot groot hoefce (tot 85 ° )

en maafc dit dus moontlik om 'n maksimale hoe-

veelheid struktuurinligting op te ncem. Die

gebruik van hierdie modulêre ontwerp sal die

latere ontwikkeling van hoëdrukselle vir stu

dies van monsters by hoe temperatuur moontlik

maak.

Die bepaling van die eksperimentele druk sal

gedoen word deur 'n standaardmetode waarby die

fluoressensiespektrum van "n robynkristalliet

(A1 20 3 + 0.5X Cr) wat by die poeiermonster in-

qesluit is , gemeet sal word. Toerusting be

st aande uit 'n helium-kadmium laser en 'n

rekenaarbeheerde spektrometer is in diens ge-

s te l . Dit sal respektiewelik gebruik word om

die fluoressensiestraling op te wek en die

spektrumverskuiwings wat deur die toegepaste

druk veroorsaak word, waar te neem.

E I E N S K A P P E V A N N A T E R I A L E

Die doelwit van hierdie Seksie is om 'n ver-

skeidenheld metodes daar te stel vir die

meting van belangrike eienskappe van materiale

wat deur die Afdelinq ontwikkel word en om

fundamentele studies oor die toestandsvergely-

king te onderneem.

Daar is drie projekte:

• Eienskappe van materiale

* Twee geborqde projekte.

EIENSKAPPE VAN MATERIALE

Die metinq van meganiese en termiese eienskap

pe van materiale word tans ondersoek, byvoor-

beeld elastisiteitsmodull, skuifsterktes en

termiese geleldingsvermoë.

Navorsingsaktlwiteite

Elastisiteitsmodull word bepaal deur die spoed

te meet waarteen ultrasonlese golwe deur 'n

monster beweeg. Hierdie metode Is reeds ver-

skeie Jare in gebruik en kan aangewend word

v1r c>ukke so hoog as 2 GPa. Die afgelope jaar

1s Merdie tegnlek toeqepas op 'n verskelden-

held enkelkrlstalle, glassoorte en qlaskera-

mleke, byvoorbeeld CoF,- en tel lur letglas.

expansion CER-VIT glass ceramic and the Mach

inable Macor glass ceramics have also been

studied.

A volumetric techt. ->ue has been developed for

conpressibility/compaction studies. The appa

ratus consists essentially of a high presssure

vrssel with a cylindrical bore. The sample is

wrapped in indium foi l and placed inside in

order to ensure conditions as close as pos

sible to hydrostatic. A piston is used to in

crease the pressure. Linear voltage to dis

placement transducers accurate to better than

1 um are used to monitor the motion or the

piston. This in turn, after correctinq for

press deformation and bore di lat ion, allows

the volume of the sample to be determined as a

function of pressure. A maximum pressure of

4 GPa can be attained.

The method can be used for both non-porous and

porous materials, thus also for powder com

pacts. In the former case the equation of

state of the material under study can be ob

tained and in the latter case one can study

the compaction mechanism of powders of indus

t r ia l importance. So far the compressibility

of several glasses of industrial importance,

as well as the compaction mechanisms of two

different types of alumina have been measured.

The glasses that were investigated are Ouran

50 (a type of pyrex glass), Macor machinable

glass ceramic, and CER-VIT glass ceramic.

Figure 4 shows the results obtained with CER-

VIT glass ceramic. The interest in this mate

r ial lies in its near zero thermal expansion

coefficient. Careful examination of this f ig

ure reveals a break in the unit volume curve

at ~0,8 GPa. This is attributed to a phase

transformation. C^P-VIT is a silica-based

polycrystalline ceramic Its crystal structure

is that of B-quartz stabilized at room temper

ature by the addition of alumina. I t is

thouqht that pressure forces this low density

structure to revert to high density a-quartz.

Studies is ook ondemeen van masjineerbare

Wacor qlaskeramieke en die CER-VIT glaskera-

mieke wat interessant is omdat dit qeen ter-

miese uitsetting tocn nie.

'n Volumetriese tegniek is ontwikkel vir

meting in saampersbaarheid/verdigtingsonder-

soeke. Oie apparaat wat gebruik word, bestaan

hoofsaaklik uit 'n hoedrukhouer met 'n s i l i n -

driese boor. Oie monster word in indiumfoelie

toegedraai en in die houer geplaas om toestan-

de so na as moontlik aan hidrostatiese druk te

verseker. 'n Suier word gebruik om druk te

verhoog. Omsetters wat verplasing na 'n

l iniêre spanning omskakel en met 'n oplosver-

moë van beter as 1 urn, word qebruik om die be-

weging van die suier te monitor. Van hierdie

met inq kan die volume van die monster as 'n

funksie van druk bepaal word nadat korreksies

vir persvervorming en booruitsetting aange-

bring is. 'n Naksimum druk van 4 GPa kan be-

reik word.

Hierdie metode kan vir sowel poreuse as nie-

poreuse materiale gebruik word en dus ook vir

saamgepakte poeiers. In die eerste geval kan

die toestandsvergelykinq van die materiaal wat

bestudeer word, verkry word en in die laaste

qeval kan die aanduiding van die meganisme van

saampakkinq vir poeiers wat van belanq is vir

die nywerheid verkry word. Tot dusver is die

saampersbaarheid van verskeie glassoorte wat

van nywerheidsbelang is, asook die saampak-

kingmeqanismes van twee verskillende tipes

alumina qemeet.

Oie glassoorte wat bestudeer is , is Duran 50

('n tipe pyrex-qlas), Macor masjineerbare

glaskeramiek, en CER-VIT glaskeramiek. Fiquur

4 toon die resultate wat met die CER-VIT qlas-

keramiek verkry is . Hierdie materiaal is van

belanq vanweê die bykans zero termiese uitset-

tingskoé'ff isiënt daarvan. Noukeuriqe onder-

soek van hierdie figuur toor. 'n buiqing in die

eenheidsvolume-kromme by ~0,8 GPa. Hierdie

verskynsel word aan 'n faseoorgang toegeskryf.

CER-VIT is 'n pollkristallyne keramiek wat op

sil ika gebaseer is . Dit het die kristalstruk-

tuur van s-kwarts wat tot kamertemperatuur

deur die toevoeginq van alumina qestabfUseer

1s. Oaar word vermoed dat die toepassfng van

This natter is being investigated by means of

ultrasonic and high pressure DTA.

druk hierdie laedigtheidstruktuur na hoér

digtheid a-kwarts terugdwinq. Hierdie ver-

skynsel word verder deur middel van ultra-

son iese en hoe'druk DTA-studies-ondersoek.

1

99

.M

97

1 .

l ,

".. '•,

' •

' - . .

? • * X

5 99 - 1

9« 1

I 1

93 - X X

92

91 (

I X

1 1 1 "

92

91 ( J 1 2 3 4

PftESSUftE/MUK(G*>

FIGURE/FIGUUR 4

Variation with pressure of the unit volume of CER-VIT glass ceramic. Values shown are normalized to atmospheric pressure

Die verandering in die eenheidsvolume vên CER-VIT glask»ramiek met druk. Die aangeduide waarde is genormaliseer na atmosferiese druk.

The density variation, with pressure, of Alcoa

A17 alumina has been measured and a variation

of behaviour appears at 1,7 GPa. This is

attributed to the onset of a new compaction

mechanism. I t has been found that A17 alumina

compacts by means of particle rearrangement

and breakage. Another alumina, A16, was also

investigated. In this case it was found that

particle rearrangement was the principal mech

anism of compaction.

Die verandering, met druk, in digtheid van

Alcoa A17 alumina is gemeet en 'n anomalie is

by 1,7 GPa waargeneem. Dit kan toegeskryf

word aan die aanvang van "n -<uwe saampakkings-

meganisme. Daar is gevind dat A17 saampak

deur herrangskikking en verbreking. 'n Ander

tipe alumina, A16, is ook ondersoek. In hier

die geval is gevind dat partikelherrangskik-

kinq die belangrikste saampakkingsmeganisme

is.

The shear strenqths of In, Sn, B i , Pb, Zn, Sb,

Ag, Cu have been measured as a function of

pressure at temperatures up to 600 °C. I t has

been found that there is an exponential depen

dence of the shear strength of these metals

with temperature. Figure 5 illustrates this

effect. A theoretical interpretation of these

results is s t i l l being investigated.

A method of determining the thermal conducti

vity of materials as a function of pressure

has been developed at the NIMR during the past

two years.

Die skuifsterktes van In , Sn, B i , Pb, Zn, Sb,

Ag, Cu is gemeet as "n funksie van druk by

temperature so hoog as 600 °C. Daar is gevind

dat die skuifsterkte van hierdie materiale "n

eksponensiële afhanklfkheid van temperatuur

toon. Die verskynsel kan in Fig. 5 gesien

word. Ondersoeke word tans gedoen om hierdie

verskynsel teoreties te verklaar.

Gedurende die 'fqelope twee jaar is 'n metode

by die NIMN ontwikkel vir die bepaling van

termiese geleidingsvermoë van materiale as 'n

funksie van druk.

The principle of the method employed is to de

termine the propagation of a plane heat pulse

through a thin disc of materia!. A computer

ized data acquisition system is used for fast

data capture. The shape and amplitude of the

heat pulse as a function of time supplies the

information required to determine the thermal

conductivity, thermal dlffuslvity and heat

capacity of the sample.

Hierdie metode berus op die beginsel van die

metinq van die voortplanting van 'n vlak h i t -

tepuls deur 'n dun skyfie materlaal. 'n Gere-

kenariseerde data-insamelirgstelsel word ge-

brulk vir vfnnige datavaslegging. Die vorm en

amplitude van die hittepuls as 'n funksie van

tyd verskaf die nodiq 1n11gt1ng om die termie

se geleldlngsvermoe, termiese dlffusle vermoe

en warmtekapasiteit van die monster te bepaal.

36

5 0 100 150 2 0 0 2 5 0

TEMPERATURE/TEMPERCnjUR PC)

FIGURE/FIGUUR 5

Shear strength of Pb as a function of temperature

Skuifsterkte van Pb as 'n funksie van temperatuur.

Figure 6 shows the results obtained for CsBr.

Results from previous investigations »rt also

included. The results agree with those in the

literature to better than TÍ which is consid

ered to be very good in the f ie ld of thermal

conductivity even at ambient pressure.

Die resultate wat vir CsBr verkry is , word in

Fig. 6 aangedui. Resultate van vorige metings

is oofc hierby ingesluit. Die huidige resul

tate is binne 7X van gepubliseerde waardes en

word vir termiese geleidingsvermoe'-metings,

selfs by kamerdruk, as baie goed beskou.

NaCl, NaBr and Nal have also been measured,

and show gratifying agreement with previous

available results.

NaCl, NaBr en Nal is ook gemeet en toon bevre-

digende ooreensterming met vorige beskikbare

resultate.

FIGURE/FIGUUR 6

Thermal conductivity of CsBr as a function of pressure. The solid tine represents results obtained fro.11 the l iterature

Termiese geleidingsvermoe van CsBr as 'n funksie van druk. Die soliede kurwe verteenwoordig literatuurwaardes.

The group at NIMR and the High Pressure Phys

ics Group of the University of Umea in Sweden

are the only groups »«ho ire able to measure

thermal conductivity of materials at high

pressure witn consistency and accuracy. A

number of other groups are also trying to

attain tills goal. Measuring the thermal con

ductivity of materials at high pressures 1s

very diff icult and various laboratories have

reported differing values, even In their own

Die groep by die NIMN en die Hoêdrukfisika-

groep by die Universltpit van Umea in Swede is

die enlgste wat ratings van termiesc gelel -

dlngsvermoë van materlale onder toestande van

hoé druk gereeld en akkuraat kan uitvoer. 'n

Aantal ander groepe pooq ook tans om hierdie

doelwlt te berelk. Meting van termiese gelei-

d1ng»vermoé van materiale onder hoe druk is

mnciHk uitvoerbaar en versklllende labora-

torla rapporteer 'n verspreiding van waardes,

37

consecutive publications. To eliminate possib le systematic errors that are causing the discrepancy, an international col laborat ive e f for t has been in i t ia ted between several groups whereby the same chosen sample w i l l be measured by a l l and the results compared. The NIMR is part ic ipat ing in th is e f f o r t .

E L E C T R O C H E M I S T R Y

The aim of this Section is to investigate the electrochemical and structural characteristics of solid electrode and electrolyte materials for battery systems. In addition this Section runs a national service for the collection of single crystal X-ray diffraction data.

There are three projects:

• Electrochemistry

• Single crystal X-ray d i f f rac t ion data col lect ion service

• A sponsored project.

ELECTROCHEMISTRY

The work th is year has centred on establ ishing the nature of electrochemical reaction mechanisms that occur durinq discharqe of l i t h ium/ transit ion-metal oxide batterv systems.

Research Activities

Over the past decade there has been considerable interest in t rans i t ion metal oxides and sulphides that are capable of revers1bl> accommodating, at ambient temperature, appreciable quantit ies of l i th ium within their structures These l i th ium insert ion/extract ion reactions with a host matrix are of both scient i f i c and technological in terest . Sc ien t i f i c a l ly these low temperature reactions provide a route for synthesizing compounds with unusual valence states and ionic ordering that cannot be prepared by conventional high temperature techniques. From a technological viewpoint, compounds that are capable of undergoing reversible topochemlcal reactions with l i th ium

sel fs in hul le eie opeenvolgende publ ikasies. Ten einde moontlike sistematiese foute wat to t hiercê ve rsk i l l e aanleiding kan gee u i t te skakel, is 'n ii,t«»rnasionale samewerkingspo-qing tussen verskeie groepe van stapel gestuur waartydens dieselfde geselekteerde monster deur almal gemeet en die resul tate vergelyk sal word. Die N1MN neem deel aan h ierd ie poging.

E L E K T R O C H E M I E

Die doelwit van hierdie Seksie is om die elektrochemiese en st rukture le eienskappe van vaste elektrode- en elektrol ietmateriaTe v i r batterysisteme te ondersoek. Verder verr ig hierdie Seksie 'n nasionale diens deur enkelkr ista l X-st raald i f f raks iedata in te samel.

Daar is dr ie pro jekte:

• Elektrochemie

• Enkelkr istal X-s t raa ld i f f raks io aata-insamelinqsdiens

• 'n Geborgde projek.

ELEKTROCHEMIE

Die aard van die elektrochemiese reaksie-meganismes wat tydens die ontlaaiproses van litlum/oorgangsmetaaloksied batterystelsels 1s hierdie jaar ondersoek.

Navorslngsaktiwlteite

Aansienlike belangstel l inq het die afgelope dekade geheers in oorqanqsmetaalok*iede en -sul f iede wat by kamertemperatuur fansienl ike hoeveelhede l i t i u m omkeerbaar in hul strukture kan opneem. Hierdie opname-/onttrekkinqreak-sies van l i t i um uf t 'n matrys is van weten-skapUke en tegnologiese belang. Op wetenskap-1 ike gebied maak hierdie laetemperatuur-reak-sies 'n s inter iser ingsroete moontlik v i r ver-blndings met ongewone valensietoestande en ionlese orde wat nie normaalweq deur konven-sionele hoetemperatuur-tegnleke berei kan word nfe. Uit 'n tegnologiese oogpunt is verbin-

ings wat omkeerbare topocberolese reaksles met l i t i um kan ordergaan van belang as elektrodes

38

are of interest as electrodes for lithium

batteries «id electrochromic displays.

The structural and electrochemical character

istics of several lithium/manganese oxide

systems have been investigated. Three-dimen

sional L i * ion diffusion at room temperature

in a cubic close-pecked oxide-ion array has

been demonstrated in the spinei-related

systems, LixMn30,, (0<x<l) and Li„[Mn2]0,,

(0,4<x<2,0). In these two systems the [Mn2]0i,

framework of the A[B2]0i, spinel structure pro

vides an interst i t ia l space of face-sharing

tetrahedra and octahedra that allows three-

dimensional diffusion of the L i * ions through

the structure.

Lithium insertion/extraction reactions result

in a reduction/oxidation of the manganese ions

in the oxide la t t ice . Insertion of one Li in

to hausmannite, the spinel Mn 2 + [Mn 2

3 + ]0 i , , pro

duces an unusually ordered rocksalt structure:

(L iMn) i 6 c [Mn 2 ] i 6 d 0„ where i 6 c and 1 6 d

refer to crystallographically non-equivalent

octahedral sites of the space group Fd3m. Re

duction of the concentration of octahedral-

site Mn3 + ions per formula unit from two in

Mn 2*[Mn 2

3 +]o„ to one in (LiMn) [Mn2]01, causes

a reduction in the cooperative Jahn-Teller

distortion of tetragonal Mn 3oH; the room-

temperature axial ratio c/a = 1,16 in Mn30\

decreases to 1,05 in LiMn30i,.

For LifMn^lO^, electrochemical data indicate

that at least 1,0 L i + may be inserted into,

and 0,6 L i + extracted from the spinel struc

ture per formula unit. Powder X-ray diffrac

tion data indicate that the [Mn2]0i, framework

of the spinel structure remains intact during

lithium insertion and extraction. This sug

gests that lithium may be cycled in and out

of the system Li i + x [Mn 2 ]0 i , over the wide

range -0,6<x<l,0. Further l i thiation of

L l i+x fM^] 0 * (Kx<3) is possible, as evi

denced by treating Ll[Mn2]0., with excess

n-butyllithium at 50 °C which yields at maxi

mum x, L1i,Mn20i, with a layered L12VSe2-type

structure.

vir litium batterye en elektrochromiese ver-

toonpanele.

Die strukturele en elektrochemiese eienskappe

van verskeie litium/mangaan oksiedsisteme is

ondersoek. Drie-dimensionele Li*-ioondiffusie

by kamertemperatuur in 'n kubies diggepakte

oksiedrangskikking is in die spinel-tipe s is-

teme, soos LixMn30\, (0<x<l) en Lix[Mn2]Oi,

(0,4<x<2,0) waargeneem. In hierdie twee sis-

teme verskaf die [Mn2]ft, raamwerk van die

A [ B 2 ] 0 I , spinelstruktuur 'n interstisiê'le ruim-

te van vlakdelende tetraëders en oktaeders wat

die drie-dimensionele diffusie van Li + - ione

deur die struktuur moontlik maak.

Litiumtoevoeging-/-onttrekkingsreaksies

veroorsaak 'n reduksie/oksidasie van die

mangaanione in die oksiedrooster. Toevoeging

van een Li in hausmanniet, die spinel

Mh 2 + [Mn 2

3 + ]0i , t het 'n ongewoon geordende

natriumchloriedstruktuur tot gevolg, naamlik

{LiMn)i 6 c [Mn 2 ] i 6 d 0„ , waar i 6 c en 1 6 d

verwys na die kristallografiese nie-

ekwivalente oktae'driese posisies van die

ruimte-groep Fd3m. Verlaging van die

konsentrasie van Mh3 +-ione in oktaëdriese

posisies per formule-eenheid vanaf twee in

Mn 2 + [Mn 2

3 + ]0 H na een in (LiMn) [Mn 2]a, lei tot

'n verminderlng in die kooperatiewe Jahn-

Teller dlstorsie van tetragonale Mn3&,; die

kamertemperatuur as-verhoudings van c/a * 1,16

in Mn30i, verminder tot 1,05 1n LiMn 30 1 ).

Elektrochemiese data dui daarop dat vir

Li[Mn2]0i, ten minste 1,0 L i * toegevoeg en 0,6

L i + per formule-eenheid uit die spinel struk

tuur verwyder kan word. X-straalpoeierdiffrak-

siedata dui daarop dat die [Mn2]0i,-raamwerk

van die spinelstruktuur tydens lltlumtoevoeg-

Ing en onttrekking onveranderd bly. Oit dui

daarop dat litium herhaaldelik in die sisteem

L i 1 + x [ M n 2 ] 0 M oor die wye gebied -0,6<x<l,0

toegevoeg en onttrek mag word. Verdere toe

voeging van litium tot Li i + x [Mn 2 ]0„ (Kx<3)

Is roontlik, soos waargeneem word as Li[Mn2]0i,

met 'n oormaat n-butiel1itium by 50 °C behan-

del word waartydens L1uMn20i,, wat 'n gelaaqde

L1 2VSe 2-tipe struktuur het, by 'n makslmum

waarde van x verkry word.

The cubic symmetry of Li[Hn2]0., is maintained

during extraction of l i th ium from the tetrahe-

dral A-si tes. However, t ransfer of one elec

tron per i n t e r s t i t i a l Li atom to the octahe

dral manganese in the reaction

xLi + Li [Mn 2 ]0„ *»L i 1 + x [Mn 2 ] 0 „

increases the t r i va len t manganese ion concen

t ra t ion su f f i c i en t l y to induce a cooperative

Jahn-Teller d is to r t ion which reduces the crys

ta l symmetry from cubic to tetragonal . A two-

phase electrode (cubic + tetragonal) resu l t s ,

which yields a constant voltage plateau at

~2,9 V in the interval 0 ,Kx<0,8. In the

range 0<x<0,l the phase is cubic and in the

range 0,8<x<l i t is tetragonal ( c / a =

1,16). In L i 2 [Mn 2 ]0 i , the l i th ium ions are

distr ibuted over both the A-sites and in ter

s t i t i a l octahedral s i tes of the spinel struc

ture. For x >1 a transformation from cubic to

hexagonal-close-packing of the anions occur:

that results in a layered structure Lii,Hh20i,

at x = 3 with manganese ions on al ternate

basal planes of .he oxygen ion array and

l i th ium in edge-shared tetrahedral s i tes of

the intervening basal planes.

Die kubiPiP simmptrie van Li[Nn2]0«, word behou tyoVns onrrr»»kkinq van l i t i um vanuit te t raë-driese A-pnsisip>.. Dip oordraq van een elek-t ron per tusvenruimt.*»! ikp I i atoom na die oktaëdriese manqaan tyripris dip reaksie

xLi + L i [Mn 2 ]0 h » L i 1 + x [ M n ? ] ( \

verhooq egter die t r i va len te mangaan-ioon-

konsentrasie genoegsaam on 'n kooperatiewe

Jahn-Teller-vervorming te bewerkstell ig wat

dan die kr istalsimmetr ie van kubies na

tetragonaal verlaaq. 'n Twee-fase elektrode

(kubies + tetragonaal) ontstaan, wat 'n

konstante spanningsplato van ~2,9 V oor die

in terva l 0,Kx<0,8 vertoon. In die gebied

0<x<0.1 is die fase kubies en tetragonaal

oor die gebied 0,8<x<l (C / a = 1,16). In

L i 2 [ H n 2 ] 0 u is die l i t iumione oor beide die

A-posisies en tussenruimtelike oktaëdriese

posisies van die spinelstruktuur versprei . Vir

x >1 vind 'n faseoorgang van kubies na heksa-

gonaal diggepak van die anione plaas wat l e i

t o t 'n gelaagde struktuur Lii»Mn2ft, by x - 3

met die mangaanione op a l t e r n a t i v e basale

vlakke van die suurstof-ioonrangskikking en

l i t i u m in die randgedeelde tetragonale posi

sies van die basale tussenvlakke.

An essent ia l ly di f fusionless t rans i t ion from

B-Mn02 to the spinel framework Li 2_ X[^"z]O"»

has also been demonstrated. This f inding is

relevant to the crystal chemistry operative in

a Y-manganese dioxide cathode of a pract ical

Li/Mn02 c e l l .

'n 8ykans d i f fus ie lose oorgang van B-Mn02 na

d ie spinel-raamwerk L i 2 _ x [Mn 2 ]0 i , word ook

waargeneem. Hierdie bevinding het betrekking

op die kristalchemie wat optree in 'n r-man-

gaandioksied katode van 'n praktiese Li/Mn02

s e l .

NATIONAL SINGLE CRYSTAL X-RAY DIFFRACTION DATA COLLECTION SERVICE

NASIONALE ENKELKRISTAL X-STRAALDIFFRAKSIE DATA-INSAMELIN6S0IENS

The single crystal data co l lect ion service

continued during the current year and data

for 131 crystals were uotained. The s ta t i s

t i c s are as fo l lows:

Die enkelkr is ta l data-insamelingsdiens is ge-durende die huidige jaar voortgesit en data v i r 131 k r i s t a l l e is versamel. Die s ta t i s t ieke is as volg:

NIMR 1 NCRL 41 Unisa 3 Nucor 1 University of the WUwatersrand 27 Rand Afrikaans Universi ty 22 University of the Orange Free State 9 University of Natal , Pietermarltzburg 7 University of Natal, Ourban 2 University of Port Elizabeth 8 University of Cape Town 10

NIMN 1 NCNL 41 Unisa 3 Kernkor 1 Univers i te i t van die Witwatersrand 27 Randse Afrikaanse Univers i te i t 22 Univers i te i t van die Oranje-Vrystaat 9 Univers i te i t van Natal , Pietermaritzburq 7 Univers i tef t can Natal, Durban 2 Univers i te i t van Port Elizabeth 8 Univers i te i t van Kaapstad 10

TOTAL 131 TOTAAL 131

40

The aim of the Electronic Materials Division is to develop expertise in the growth, processing and characterization of electronic materials and to apply th is expertise to the study and development of part icular semiconductor mater ials.

There ire f i ve projects:

Semiconductor Technology

Four sponsored projects.

S E M I C O N D U C T O R T E C H N O L O G Y

The aim of th is project is to grow and develop semiconductor c rys ta ls , polycrystal l ine layers and epi taxia l layers and to develop the techniques for the characterization of these mater i a l s as regards the i r e lect ronic , opt ical and structural propert ies.

Research Activities

The ac t i v i t i es of the 01v1s1on in the execut ion of th is project may be divided into the areas of crystal growth, contact fabr icat ion and opto-electronic character izat ion. Whilst the contact fabr icat ion f a c i l i t i e s of the Division have been established recently, s ign i f icant progress has been made in the crystal growth and opto-electronic characterization areas.

E L E K T R O N I E S E M A T E R I A L E

H Booyens Head of Division / Afdelingshoof

Die doel van die Afdeling Elektroniese Mate-r i a l e is om kundigheid te ontwikkei in die qroei , prosessering en karakterisering van elektroniese materiale e> om hierdie kundigheid toe te pas op die bestudering en ontwikkei ing van spesif ieke hal fgele iermater ia le.

Daar is vyf projekte:

• Halfgeleiertegnologie

• Vier qeborgde projekte.

H A L F 6 E L E I E R T E 6 N 0 L 0 G I E

Die doel van hierdie projek is om ha l fge le ier -k r i s t a l l e , po l i k r i s ta l l ag ies en epi taksiële lagies te groei en te ontwikkei en om tegnieke te ontwikkei v i r die karakter iser ing van h ierdie materiale wat hul elektroniese, optiese en strukturele eienskappe betref .


Die ak t iw i te i te van die Afdeling in die u l t -voering van h ierd ie projek kan verdeel word in die qebiede van k r i s t a l q r o e i , kontakfabrise-r ing en optoe'lektroniese kar*k ter iser ing. Terwyl die kontakbereidinq f a s i l i t e i t e van die Afdeling onlangs qevestig i s , is noemenswaar-dige vorderinq reeds qemaak op die k r i s t a l -groei- en optoe'lektroniese karakterlseringsge-biede.

41

atrsTN. atom» HUSTM.GMEI

• Liquid Phase Epitaxy

This technique is being employed to produce

epi tax ia l layers of HgCdTe on single crys

ta l CdTe substrates. Construction of the

apparatus was completed early in 1984 and

the present work is directed towards gain

ing control over Hg vapour pressures and Cd

segregation during growth.

Hg loss leads to the growth of Hg-poor

HgCdTe and loss of control over growth

condit ions. Figure 7(a) shows a quenched

non-stoichiometric melt used for LPE growth

of Hg0 8 C d 0 > 2 T e . The l igh t areas are

HgCdTe of varying composition while the

dark areas are Te. Figure 7{b) shows a

s imi lar melt after LPE growth. Pract ic

a l l y a l t the Hg has evaporated leaving

CdTe crystals embedded in Te. This prob

lem has been p a r t i a l l y overcome by using

in-house grown Hgo 8 Cd 0 2Te as source

material for mel t -equ i l ib ra t ion . F ig

ure 8 shows an epi taxia l layer of

Hgo o5Cc)o 95 T e grown using a source

crystal of Hg0 &CdU t 2Te prepared by

so l id state rec rys ta l l i za t i on . The growth

temperature was 500 °C and the composition

of the melt was 19:1:80 Hg:Cd:Te.

I t is planned to improve on the Hg vapour

control by using a separately heated Hq

supply to generate a Hg overpressure of 0,1

atmosphere, corresponding to the equ i l i b

rium vapour pressure of Hg over the melt.

• Solid State Recrystallization

This technique is being used to prepare

bulk crystals of Hg0 8Cdo 2Te for gene

ra l studies. The technique consists of

quenchfnq a near-stoichiometric pseudo-

binary melt and annealing the resul t ing

boule just below the solldus temperature to

ef fect grain growth. The quenched Ingot is

dendrit ic in nature as shown in F ig. 9.

• Vloeistoffase E p i t * s i e

Hierdie tegniek word tans gebruik on ep i -

taks ië le lagies van HgCdTe op enkelkr istal

CdTe substrate te g roe i . Konstruksie van

die apparaat is vroeg in 1984 vol tooi en

die huidige werk is toegespits op die be-

heer van Hg-dampdruk en Cd-uitskeiding

tydens die qroeiproses.

Hg-verlies le i to t Hg-arm HgCdTe en die

ver l ies van beheer oor die groeitoestande.

Figuur 7(a) toon 'n g?b1uste n ie -s to ïg io -

metriese smelt v i r gebruik in die LPE-

groeiproses van Hg0 8 Cd 0 2 Te . Die l i g t e

areas bestaan u i t HgCdTe van wisselende

samestelling terwyl die donker areas u i t

Te bestaan. Figuur 7(b) toon 'n soort-

gelyke smelt na die LPE-qroeiproses. Fe i t -

l i k al die Hq net verdamp en het CdTe-kri-

s t a l l i e t e agtergelaat in 'n matriks van Te.

Hierdie probleem is gedeeltel ik te bowe ge-

kom deur Hg0 8 Cd 0 2 Te wat in die Afde-

l ing gegroei is as bronmateriaal om die

smelt in ewewig te br ing. Figuur 8 toon

'n epi taksiële lagie van Hg0 osCd0 9 5 T e

wat gegroei is met behulp van 'n bronkr i -

s ta l van Hg0 „Cd 0 2Te wat deur middel

van vastetoestand herk r i s ta l l i sas ie voor'je-

re i i s . Die groeitemperatuur was 500°- ' en

die smeltsamestelling was 19:1:80 Hg:Cd:Te.

Verbeterde beheer oor die Hg-damp word be-

plan deur die gebruik van 'n afsonderlik

ve rh i t te Hg-oron om 'n Hg-oodruk van 0,1

atmosfeer op te wek. Hierdie drjk stem

ooreen met die ewewigsdampdruk van Hq bo

die smelt.

• Vastetoestand Herkristallisasie

Hierdie tegniek word qebruik om volume-

k r i s t a l l e van Hg0 eCda 2Te v i r algeme-

ne studies te bere i . Die tegniek bestaan

u i t die blus van 'n naby-stoTgiometrlese

pseudo-binêre smelt en die daaropvolqende

u l tg loe i inq van die verkryqde boule net

benede die solldustemperatuur om sodoende

korrelgroef te bewerkstel l ig. Die gebluste

42

FIGURE/FIGUUR 7

Before growth and Hq-loss trie au»nched melt is characterized by l iaht c rys ta l l i t es of HgCdTe of varying composition and dark regions of Te interspersed with rpqions of eutectic

After growth and extensive Hg-loss the m?lt consists largely of Te with needlelike crystals of CdTe

Voor groei en Hq-verlies word dip qeblaste smelt gekarakteriseer deur l i q te k r i s t a l -l iete va.i HqCdTe w t wisselende samestel-ling en donker areas van TP mpf a'-eas van eutektikum tussenin.

Ha groei en uitgebreide Hg-verlies bestaan die smelt hoofsaaklik uit Te met naaldag-tiqe CdTe-kristalle

10 urn

FIGURE/FIGUUR 8

Optical Nomarski microqraph of a (HqCd)Te epitaxial layer grown on a CdTe substrate by means of l iq uid phase epitaxy

Optiese Nomarski mtkrograaf van 'n (HgCd)Te epitaksiële lagie ge-qroei op 'n CdTe-substraat deur middel van vloeistoffase epitaksie

43

The subsequent hiqn temperature anneal (150 hours at 650 "C) -esults in larqe qrain (tin-size) mater ia l . Hqure 10 shows the boundary reqion between two grains in annealed crystal delineated by a Polisar 2 etch. As indicated by the t r ianqular shapes o c the dis 'ocat ion e tch-p i ts , the or ientat ion of one of the qrains is near (111). Some low anql-3 qrain boundaries are also v i s i b l e .

FIGURF/FIGIIUR 10 The boundary reqion betwepn grains in annealed so l id state recrystal I ucA mater ia l . The qrain on the le f t has a r\e*r (111) or ientat ion as may be deduced from the tr iangular e tch-p i ts . Some iow-annle qrain boundaries are> also in evi denc°.

Die qrensq»bifd tussen korrels in uitqoqloeide vastetoestand-herkristrfi ! ise^rde materiaal. Die korrel links he' 'n amper-( l l l ) orient, as ie soos afgelei k,in word uit dip driehoekiqe aard van die etspwtte. 'n Paar lae-hoek ko r re l -qrense is ook siqbaar.

boule is dendrities van aard soos qetoon in Fiq. 9. Die daaropvolqende hoe temperatuur uitgloeiproses (150 uur teen 650 °C) lei tot groot-korrel (mm-grootte) materiaal. Figuur 10 toon die grensgebied tussen twee korrels in 'n uitgegloeide-kristaJ qeëts met "n Polisar 2 ets. Soos aangedui deur die driehoekiqe vorms van die ontwrigtings-etsputte, is die orientasie van die een korrel na aan (111), 'n Aantal lae-hoek korrelgrense is ook siqbaar.

FIGURE/FIGUUR 9

The dendritic nature of as-quenched Hq0 pCd 0 2

T e bulk crystals prepared 6y solid state recrystallization. The dendritic regions are CdTe-rich

Die dendritiese aard van soos-gebluste Hg0 8Cd 0 2Te-volumekristalte wat deur vasietoestand herkristallisasie voorberei is. Die dendritiese gebiede is CdTe-ryk

FIGURE/FIGUUR 11 A Te inclusion in annealed (HqCd)Te grown by solid state recrystallization. The density of etch-pits increases toward the inclusion, indicative of the increased stress near i t being rel ieved by dis locat ions.

'n Te- ins lu i t inq in uitqeqloeide (HqCd)Te qe-qroei deur vastetoestand-herkr is ta l l iser ing. Di° diqtheid van etsputte neem toe in die nabyheid van die i n s l u i t i n q , 'n aanduiding dat toenemende 'panninq na daaraan deur ontwrig-t inqs ver l iq word.

44

The material produced in this «ay generally suffers from two drawbacks, namely, Kg vacancies and Te inclusions. Figure 11 shows a Te inclusion with a high density of etch-pits in its immediate vicini ty, indicative of the high latt ice strain relieved by dislocations in this mechanically soft materia l . This problem is at present being treated by employing a Hg excess durh.j the growth procedure.

OPT0-ELECTRORIC CHARACTERIZATION

Much effort has been directed at the determination of the net electronic concentration in the HgCdTe material produced by the above solid state recrystallization technique. To this effect the Hall analysis system has been adapted to allow measurement at controlled temperatures down to 10 K. The narrow bandgap of Hg0 gCdo 2ê m < s shallow impurity energy levels necessitates the use of such low temperatures.

In Fig. 12 the Hall coefficient of the material described above is given as a function of temperature (curve (p) ) . The sign of the Hall coefficient is negative at high temperatures where the material is tzsentially intrinsic, due to the large electron-hole mobility rat io. At lower temperatures, where the material is extrinsic, the Hall coefficient goes to zero and becomes positive, indicative of p-type material. The doping concentration is determined by employing the analysis techniques developed as part of the theoretical effort within the Division and is found to be 6 x 101 cm"3. This relative'y heavy doping is ascribed to the Hg vacanci?s mentioned above which act as eK^tron acceptors.

(HgCcl)Te of 6 x 10 1 7 cm'3 p-doping is not at all suitable for photoconductive infrared detection applications and has to be annealed in a Hg overpressure at approximately 250 °C for 14 days in order to remove Hg vacancies. The resulting material has been analysed as n-type as shown in Fig. 12 (curve (n) ) . The curve is characteristic of n-typc material and gives a doping concentration of 3 x 10 1 5 cm"3.

Die materiaal wat so berei word, net ge-woonlik twee tekortkoannge, naamlifc Hg-leemtes en Te-insluitings. Figuur 11 toon 'n Te-insluiting Met 'n ho* etsputdigtheid in die onmiddellike nabyheid, wat dui op 'n hoé roostervervorminq wat verlig word deur ontwrigtings in hierdie meganies sagte ma-te r iaa l . Die probleen word tans behandel deur 'n Hg-oomaat gedurende die groei-proses te gebruik.

OPTOeLEKTRORIESE KARAKTERISERINS

'n Groot poging is gerig op die bepaling van die netto elektroniese draerdigtheid in die HgCdTe materiaal wat deur middel van boger.oem-de vastetoestand herkristallisering berei is . Die Hall-analisesisteem is dus aangepas om metinge by gekontroleerde temperature tot so laag as 10 K te bewerkstellig. Die nou band-gaping van Hg0 „Cd0 2 Te en vlak onsuiwer-heidsenergievlakke vereis die gebruik van hierdie lae temperature.

In Fig. 12 word die Hall-koeffisient van boge-noemde materiaal as 'n funksie van temperatuur (kurwe (p)) getoon. Die teken van die Hal l -koëffisient is negatief by hoë temperature waar die materiaal intrinsiek is as gevolg van die groot elektron-holte mobiliteitsverhou-ding. By laer temperature, waar die materiaal ekstrinsiek is , word die Hal1-koeffisient zero en daarna positief, wat 'n aanduidinq van p-tipe materiaal is . Die doteringskonsentrasie word op 6 x 10 1 7 cm"3 bepaal deur die ontle-dingstegnieke wat ontwikke! is as deel van die teoretiese poging binne die Afdeling. Hierdie relatief hoë dotering «ord toegeskryf aan die bogenoemde Hg-leemtes wat as elektron aksep-tors optree.

(HgCd)Te met 6 x 10 1 7 cm"3 p-dctering is ge-heel en al onbruikbaar vir fotogeleidende infrarooi-opsporingstoepassings en moet in 'n Hq-bodruk by onqeveer 250 °C vir 14 dae uitge-gloei word om Hq-1eemtes te verwyder. Die materfaa! wat op hierdie wyse verkry word, is geanaliseer en is van n-tipe aard soos in Fig. 12 (kurwe (n)) aangetoon. Die kurwe is tipies die van n-tfpe materiaat en gee 'n doteringkonsentrasie van 3 x 10 1 5 cm"1.

45

iHkílt t-

< C M J ^ C ) I

» » < • » « » » • • » » • "• »

lee -

i B \ . . .

• *

i e ?B 30 iaee^TíK)

40

Another important electronic parameter is the minority carrier lifetime of excited charge carriers and an apparatus is at present being designed to determine this quantity in HgCdTe.

se

FI6URE/FIGUUR 12

The Hall coefficient of Hgo>8Cdo.2Te before a second anneal in Ho vapour to remove vacancies (curve (p)) and after such an anneal (curve (nj)

Die Hall-koeffisient van Hg 0, aCd 0 >2Te voor 'n tweede uitgioeiing in kwikdamp om leemtes te verwyder (kurwe (p)) en na die uitgioeiing (kurwe (n))

'n Verdere belangrike elektroniese parameter is die minderheidsdraerleeftyd van opgewekte ladingsdraers en 'n apparaat word tans ontwerp om hierdie hoeveelheid vir HgCdTe te bepaal.

CONTACT FABRICATION K0RTAK8EKIDIHG

The realization of electronic contacts onto semiconductors is a fundamental requirement for electronic characterization and device development. The Division has thus built up fac i l i t ies durinc tne past year for the fabr i cation of ohn.ic and rectifying cont.'t' ' to a number of semiconductors. At presint the major problem is the fabrication of low resistance ohm 1c contacts to wide bandgap materials such as GaAs. The measurement of contact resistances of the order of 10" 7 8 cm2 is also very d i f f icu l t .

Die realisasie van elektroniese kontakte op halfgeleiers is 'n basiese vereiste vir alek-troniese karakterisering en toestelontwlKke-l ing. Die Afdeling het Jus gciurende die af-gelope jaar fas i l i te i te o^gebou om ohmiese en gelykrigter»^ kontakte op verskeie halfgeleiers te berei. Tans is die grootste pro-bleem die bereiding van lae weerstand ohmiese kontakte op wye bandgaping materiale soos GaAs. Die bepaling van kontakweerstande van die ordeqrootte 10"7 n cm2 is ook baie moei-Hk.

The problem of measuring low resistance contacts has been studied in the Division and a concentric ring contact pattern developed, based on a transmission line model. This system overcomes some of the practical problems associated with rectaigu'ar test patterns and will prove most useful in contact assessment.

Die probleem on 1ae kontakweerstande te bepaal is binne die Afdeling bestudeer en 'n konsen-trlsering kontakpatroon gebaseer op die trans-tnlssielynmodel is ontwikkel. Hierdie sisteem kom sommige van die praktiese pr obi erne ver-bonde aan reghoekige toetspatrone te bowe en sal baie goeie toeoassing in kontakmetinge vind.

PHOTOSENSITIVE PbS F0T0SERSIT1EHE PbS

The chemical deposition of PbS has received considerable attention during the past year in

Die chemiese neerslag van PbS het oor die af-gelope jaar baie aandag geniet in 'n poging om

46

«i attempt to gain control over the Materials properties via growth parameters. To achieve th is . Material was evaluated using photocon-ductive decay lifetime measurements, noise measurements and responsivity analyses. Figure 13 shows a photoconductive decjy (PCO) signal obtained fro* a typical sensitized PbS layer with a lifetime of approximately 300 us. By relating the results of these measurements to growth parameters the preparation technique has been standardized to the point where material may be produced with PCO lifetimes up to 500 us or more and with detectivities routinely in excess of 10 1 0 (cm Hz l % H" 1 ) . Figure 14 shows the polycrystalline nature of typical photosensitive PbS layers prepared by the standardized technique.

via die groeiparameters beheer oor die mater i-aal-eienskappe te verkry. Vir nierdie doel is materiaal deur die gebruik van fotogeleiding-verval- leeftydmetinge, ruismetinge en respon-s iwi te i tanal ises geëvalueer. Figuur 13 toon 'n fotogeleiding-verval (PCD) sein wat verkry is van 'n t ip iese gesensitiseerde PbS-lagie met 'n leeftyd van onqeveer 300 vs. Deur die resul ta te van hierdie metinge 'net groe'-toestande in verband >e br ing , is die voor-bereidingsteqniek gestandaardiseer tot op "n punt waar materiaal voorberei kan word met PCD-leeftye so hooq as 500 ws of meer en met roet ine waarneembaarheid \/an neer as 10 1 C

(cm Hz 2 H" 1 ) . Fiquur 14 toon die p o l i -k r i s ta l l yne aard van 'n t ip iese fotosensitiewe PbS-lagies wat deur die gestandaardiseerde proses voorberei i s .

T (ms) FIGURE/FIGUUR 13

A photoconductive decay curve for a typical layer of sensitized polycrystalline PbS

FIGURE/FIGUUR 14

Scanninq electron microqraph of a typical PbS po lycrysta l l ine layer prepared by th^ standardized technique developed in the Electronic Materials Division

'n Fotogeleidlngsverval kurwe vir 'n tipiese lagie gesensitiseerde polykristallyne PbS

Skandeer-elektronmikroqraaf van 'n t ip iese PbS po l i k r i s t a l l ag i e voorberei deur die gestan-daardiseerde tegniek wat in die Afdelinq Elektroniese Materiale ontwikkel is

47

M A T E R I A L S C H A R A C T E R ! -2 A T I O N

M A T E R I A A L K A R A K T E R I S E -R I H 6

The aim of the Materials Characterization Division is to provide a service in the determination of the chemical and structural composition of samples by means of physical in strumentation. This involves determination of the overall chemical composition of bulk samples, the microchemical compositional d is t r i bution within bulk samples and near their surfaces, and the nature of the crystal defect structure and its distribution within samples. These services are available to the NIMR, other institutes of the CSIR, outside organizations and industry. In addition, the Division collaborates with other divisions on lonq term research problems.

The expertise required for the application of the physical instrumentation mentioned above, is generated by conducting research within NIMR-related f ie lds. The Division is structured into the following six sections:

• Atomic Spectroscopy

• X ray Fluorescence Spectroscopy

• Mass Spectroscopy

• Surface Science

• Electron Microscopy

• Electronic Development and Automation .

J T Fourie Head of Division / Afdelingshoof

Die doel van die Afdeling Materiaalkarakceri-sering is om 'n diens vir die bepaling van die chemiese en strukturele samestelling van monsters met behulp van fisiese instrumentasie te verskaf. Dit behels die bepaling van die chemiese geheelsamestelling van grootmonsters, die mikrochemiese samestellingsverspreiding binne qrootmonsters en na aan hul oppervlakke, en die aard van kristaldefekstruktuur en die verspreiding daarvan in monsters. Hierdie dienste is beskikbaar aan die NIMN, ander institute van die WNNR, orqanisasies van buite en die nywerheid. Die Afdeling werk ook met ander afdelinqs saam ten opsigte van lanqter-myn navorsingsprobleme.

Die kundigheid nodig vir die toepassinq van bogenoemde fisiese instrumentasie, word opge-bou deur navorsing op gebiede wat met die NIMN verband hou. Die Afdeling is in die volgende ses seksies vcdeel:

• Atoomspektroskopie

• X-straalfluoressensie-spektroskopie

• Massaspektroskopie

• Oppervlakwetenskap

• Elektronmikroskopie

• Elektroniese Ontwikkeling en Outomatisasie.

48

A T O N I C S P E C T R O S C O P Y

A considerable number of samples f ro» other Divisions of the NIMR, the CSIR and industry are analysed regular ly . The analyt ical techniques used are

• atomic absorption with flame and graphite

tube as atomizers

• atomic emission with glow discharge and

inductively coupled plasmas as exci tat ion

sources.

Research on these techniques is aimed at improving the qual i ty of the analyses.

ATONIC ABSORPTION SPECTROMETRY

Atomic absorption spectrometry, although a single element technique, is intensively used in analyses due to i t s general app l i cab i l i t y to most elements. Research i s , however, centred on the graphite tube technique. The purpose of research in th is f i e l d is to develop a method for calculat ion of the graphite tube temperature as a function of posi t ion and time to determine the optimum tube shape and to test tubes coated with pyro ly t ic carbon for the determination of refractory elements.

Research Ac t i v i t i es

A computer program was developed for calculat ion of the tube wall temperature as a funct ion of posi t ion and time. This was based on a physical model of the tube which took res is tance heating, radiat ion absorption and conduction into account as energy gains, and ra diat ion and conduction as energy losses for each tube segment. Four di f ferent tube shapes w re tested and the knowledge gained in th is tay w i l l be used to design a f i na l shape. .his tube w i l l then be thoroughly evaluated as regards sens i t i v i t y and degree of freedom from chemical interference.

A further advantage of the temperature calculat ion technique was that It was possible to design a graphite tube capable of delaying

A T O O N S P E K T R O S K O P I E

Heelwat monsters van ander Afdelings van d ie NIHN, die UNNR en die nywerheid word gereeld ontleed. Die anal i t iese tegnieke wat gebruik word, is

• atoomabsorpsie met vlam en graf ietbuis as

atomiseerders

• atoomemissie met gl imontlading- en induk-

t i e f gekoppelde plasmas as opwekkingsbron-

ne.

Navorsing op hierdie tegnieke is geriq op d ie verbeterinq van die kwal i te i t van die on t le -dings.

ATOtMABSORPSIESPEKTROKTRIE

Atoomabsorpsiespektrometrie, alhoewel 'n enkel-element tegniek, word intensief in ont-ledings benut weens die wye toepasbaa^heid op die meeste elemente. Navorsing is egter op die graf ietbuistegniek gefokus. Die doel van navorsing op hierdie gebied i s om 'n metode te ontwikkel v i r die berekening van die g r a f i e t -buistemperatuur as 'n funksie van posisie en tyd ten einde 'n optimum buisvorm te v ind, en om graf ie tbuise wat met p i r o l i t i e s e koolstof bedek is v i r vuurvaste elemente te toets.

NavorsingsaktIwitelte

'n Rekenaarprogroro is ontwikkel v i r die berekening van die buiswandtemperatuur as 'n funksie van posisie en tyd . Dit berus op 'n f i s iese model van die buis wat weerstandsver-h i t t i n g , stral ingabsorpsie en geleiding as energiewinste, en u i t s t r a l l ng en geleiding as energieverl iese v i r elke segment van die buis in ag geneem. Vler verski l lende bulsvorms is getoets en die kennis so ingewln sal aangewend word om 'n f ina le vorm te ontwerp. Hierdie buis sal dan deeqlik ten opsigte van s e n s i t i -w l t e i t en mate van vryheid van chemiese steu-rlngs evalueer word.

'n Verdere voordeel van die temperatuurbereke-ningstegniek was dat d i t moontlik geword net om 'n graf ietbuis te ontwerp wat atomisering

atomization. This effect is required to delay

atowization of elements of medium and qreater

v o l a t i l i t y so as to have th is process taking

place only when the gas temperature in the

tube is high enough. Calculated values for

d i f ferent tube shapes showed that th is e f f t t t

can be obtained with a tube having a thicker

centre section where the sample is deposited.

Commercial cubes are completely unsuitable for

uranium and boron determination. Under the

required conditions commercially coated tubes

have a l i fe t ime of less than 10 temperature

cycles, while commercial standard tubes (un-

coated) have 3 l i fe t ime of about 20 cycles

before these two elements are bound as the

carbides to an undesirable extent. The tubes

machined and coated in th is laboratory have

suf f i c ien t resistance to degradation at the

required high temperatures and to the inner

surface erosion accompanying carbide forma

t i o n , to permit an adequate number of measure

ments to be made for an analysis.

In the case of boron and uranium, erosion is

caused by the continual formation and d issoc i

ation of carbides as well as by the high tem

peratures required to eliminate (boron) or

l im i t (uranium) the memory e f fec t .

Tubes manufactured at the NIMR have for some

time been used in analyt ical applications of

the graphite furnace technique. By thermal

decomposition of methane gas a thick (~50 wn)

pyro ly t ic carbon layer is deposited on the

tube which is heated by e lec t r i ca l resistance

heatinq. Tubes coated in th is way have been

tested for determination of uranium and boron

and have a l i fe t ime of 150 to 200 uranium

determinations using atomizing temperatures of

2 700 to 2 800 °C. The l im i t of detection is

0,5 ppm for uranium and 0,015 pom for boron.

RAPID MULYSIS BY ATONIC EMISSION SPECTROMETRY

The aim of the project is the use of the i n

duct ively coupled plasma and the glow d is

charge lamp for analyt ical measurements, as

well as research on the excitat ion conditions

ex is t ing in these sources.

kan vertraag. Oie effek is nodig om atonrise-

r ing van elemente van medium en groot v l ug t i g -

heid te vertraag sodat h ierd ie proses eers

plaasvind wanneer die gastemperatuur in die

buis hoog genoeg i s . Berekende waardes v i r

verski l lende buisvorms toon dat hierdie effek

verkry kan word met 'n buis met 'n verdikking

in die middelste deel waar die monster gedepo-

neer word.

Kommersiê'le buise is hoegenaamd nie geskik v i r

uraan- en hoorbepaling n ie . Onder die vereiste

toestande het die kommersieel-bedekte buise 'n

leeftyd korter as 10 temperatuursiklusse, t e r -

wyl die kommersiële standaardbuise (onbedek)

slegs v i r ongeveer 20 siklusse bruikbaar is

voordat die twee elemente in 'n ongewenste

mate as die karbiede gebind word, daarenteen

het die buise wat in hierdie laboratorium ge-

maak en bedek word, genoeg same weerstand teen

verwering by die vereiste hoë temperature en

die binne-oppervlakverwering wat met karbied-

vorming gepaard gaan om die nodiqe aantal

metings v i r 'n ontleding te kan maak.

In die geval van boor en uraan word erosie

veroorsaak deur die voortdurende vorming en

ontbinding van karbiede asook deur die hoé

temperature wat nodig is om die geheue-effek

te elimineer (boor) of te beperk (uraan).

Buise wat in die NIrN vervaardig word, is

reeds geri'ime tyd in gebruik v i r anal i t iese

toepassings van die grafietoondtegniek. 'n

Dik (~50 urn) p i r o l i t i e s e koolstoflaag word

verkry deur die termiese ontbinding van

metaangas en gelyktydige neerslag op die weer-

standverhitte bu is . Buise wat op hierdie wyse

bedek i s , :• v i r die bepaling van uraan en

boor getoets en het 'n leeftyd van 150 to 200

uraanbepalings met atomiseringstemperature van

2 700 tot 2 800 ° C . Oie bepalingsqrens van

uraan is 0,5 dpm en van boor 0,015 dpm.

VIMI1GE OWTLEOIMG DEUR ATOOMEMISSIESPEKTRO-«TRIE

Oie doel van die projek is die qebruik van die

induktief-gekoppelde plasma en die gl imont la-

dinqslamp v i r anal i t iese metinqs, asook

navorsing oor die opwekkingstoestande wat in

hierdie bronne heers.

5C

The report of the Working Group on Materials Characterization Support for th* miMR (IMAT 1) showed that stringent demands are made on the Division for analysis of materials for the metals development research programmes of the Institute. In the past year the highest priority was given to the endeavour to expand the analytical service.

The available direct reading RSV vacuum spectrometer has been put in... operation for the purpose of relieving the pressure on the existing analytical f ac i l i t i es .

Research Activities

- RSV V K W M Spectroaeter

The advantages, amongst others, of the system are

• • simplicity of sample preparation, •• simultaneous multi-element analysis • • a minimum of matrix effects.

The apparatus was set up to determine quant i ta t ive ly the following 18 elements: P, S, C, S i , B, Mn, Fe, A l , Cr, Co, Cu, Mo, Nb, Ni , T i , V, W and Zr.

As a result of the upper spectral limit of 350 nm and the need for optimum uti l izat ion of the vacuum region below 200 nm, i t was necessary to find interference-free and sensitive spectral lines other than those generally used in analytical programs. These lines had to be such as to serve for both the Iron and nickel base alloys. Three separate data bases are being established for low and high alloy steels and nickel-base materials. This implies the use of regression techniques for concentration calculations using various sputtering, matrix and line interference correction factors.

ANALYTICAL ADO DIAGNOSTIC STUDIES USIN6 ATONIC FLUORESCENCE SPECTROMETRY

Since the Section has for some time been Involved in the study of excitation sources, i t

Die verslag van die Uerkgroep oor Materiaalka-rakteriserinQsonderstejning vir die MIHN (IMAI 1) toon dit hoe eise aan die Afdeling gestel word vir die analise van nateriaal v ir die metaalontwikkelingnavorsingsprogramne van die Instituut. Die poging om die analitiese diens uit te brei het die afgelope jaar die hoogste priori tei t geniet.

Ten einde die druk op bestsande analitiese f a -s i l i t e i t e te verl ig, is die beskikbare direk-lesende RSV-vakuumspektrometer in bedryf ges te l .

RawtMTsingsaktiwiteite

• RSV-VakwMspektroaeter

Die voordele van die sisteem is onder andere

•• eenvoudige monstervoorbereiding •• gelyktydige veelelementontledings •• minimum matrikseffekte.

Die analitiese program is saamgestel om die volgende 18 elemente kwantitatief te be-paal: P, S, C, S i , B, Mn, Fe, A l , Cr, Co, Cu, Mo, Nb, N i , T i , V, W, en Zr.

Weens die boonste spektraalbeperking van 350 nm en die vereiste vir optimum benut-ting van die vakuumgebied onder 200 nm, was dit nodig om ander steurinqsvrye en sensi-tiewe spektraallyne te vind as die wat a l -gemeen in analitiese programme gebruik word. Die lyne moet vir beide die yster-en nikkelbasisleqerinqs diens kan doen. Drie afsonderlike databasisse vir lae- en hoëlegerinqstaalsoorte en nikkelbasismate-r ia le word saamgrstel. Oit behels regres-sietegnieke vir konsentrasleberekenings deur die qebruik van verskillende verstui-wing-, matriks- en lynsteuringkorreksiefak-tore.

ANALITIESE EN DIAfiNOSTIESE STUDIES NET GEBRUIK VAN ATOOMFLU0RESSENSIESPEKTR0NETRIE

Aangesien die Seksie reeds 'n geruime tyd met die ondersoek van opwekkinqsbronne gerooeid is ,

r;1

«as decided to use the opportunity of working

at the Co-operative Research Centre of the

European Common Market countries in Ispra,

I t a l y , to carry out research on the appl ica

b i l i t y of a tunable dye laser as exci tat ion

source.

Research Activities

• Atoaic fluorescence spectrometry «nth a dye laser as excitation source

Research was carried out regarding the use

fulness of a tunable dye laser as exci ta

t ion source for analyt ical atomic f luores

cence measurements as well as for diagnos

t i c measurements of plasma temperatures by

means of atomic fluorescence. Using an i n

ductively coupled plasma (ICP) as atomizing

medium for l iqu id samples and a laser as

excitat ion source, excellent sens i t i v i t i es

were obtained for the 14 elements inves t i

gated (mainly refractory elements such as

T i , 6, Mo, U). In comparison with the ICP

emission technique, th is system gave more

or less similar detection l imi ts for B, Ba,

Mo, T i , V and Zr; approximately ten times

lower detection l imi ts for S i , Sn, TI and

Y, and detection l imi ts about f i f t y times

lower for A l , Ga, Pb and U. Non-resonant

fluorescence was measured throughout, i .e .

the excitation and fluorescence wavelengths

d i f fe red. Apart from i ts good s e n s i t i v i t y ,

the most important advantage of the tech

nique is i ts prac t ica l ly absolute freedom

from spectral interference.

The spatial d is t r ibu t ion of the gas temper

ature in the ICP could be measured by use

of a narrow laser beam for exc i ta t ion of

the OH fluorescence spectrum in the region

306,4 - 315,0 nm. I t was found that the

temperature at the axis of the plasma is as

low as 1 000 K while i t increases to a max

imum of approximateIv 3 500 K at between 3

and 4 mm from the axis, with a gradient of

1 000 K/nm between 2 and 3 mm from i t .

These results have far reaching implica

tions when considering the ambient chemical

atmosphere of the analyte.

is beslu i t om die geleentheid te benut om by

die Gesamentlike Navorsinqsentrum van die

Europese Gemeenskapsmarklande, Ispra, I t a l i ë ,

te werk, deur navorsing te doen oor die bru ik -

baarheid van 'n instembare kleurstof laser as

opwekkingsbron.


• Atooafluoressensiespektroaetrie Met 'n kleurstoflaser as opwekkingsbron

Navorsing is gedoen oor die bruikbaarheid

van 'n instembare k leurstof laser as opwek

kingsbron v i r anal i t iese atoomflucressen-

siemetings sowel as v i r diagnostiese tempe-

ratuurmetings van plasmas deur middel van

atoomfluoressensie. Met 'n induktief-gekop-

pelde plasma (IGP) as atomiseringsmedium

v i r vloeibare monsters en 'n laser as op

wekkingsbron is u i ters goeie sens i t iw i te i te

behaal vir die 14 elemente wat ondersoek is

(hoofsaaklik vuurvaste elemente soos T i , B,

Mo, U). In verqelyking met die IGP-eim'ssie-

tegniek het d i t ongeveer golyke bepalings-

grense gelewer v i r B, Ba, Mo, T i , V en Zr;

ongeveer t ien keer laer bepalingsgrense v i r

S i , Sn, TI en Y, en ongeveer vy f t ig keer

laer vf r A l , Ga, Pb en U. Nie-resonante

fluoressensie is deurgaans gemeet, d i t wi l

sê die qolf lenqtes van opwekking en f l uo

ressensie het v e r s k i l . Afqesien van die

qoeie s e n s i t i w i t e i t , is die belangrikste

voordeel van die tegniek die f e i t l i k abso

lute vryheid van spektrale steuri. igs.

Deur gebruik te maak van 'n dun laserbundel

v i r die opwekking van die OH-fluoressensie-

spektrum in die gebied 306,4 - 315,0 nm,

kon die p j lmte l ike d is t r ibus ie van die gas-

temperatuur in die IGP qemeet word. Dit het

aanqetoon dat die temperatuur op die as van

die plasma so laag as 1 000 K i s , terwyl

d i t toeneem na '* maksimum van ongeveer

3 500 K tussen 3 en 4 mm vanaf die as, met

'n gradient van 1 000 K/mm tussen 2 en 3 mm

vanaf die as. Hierdie resultate het ver-

reikende implikasies by die beskouing van

die chemiese atmosfeer wat die anal let om-

r i n g .

52

X - R A Y F L U O R E S C E N C E S P E C T R O S C O P Y

The aims of the Section are to meet the re

quirements of industry and of CSIR Inst i tu tes

for rapid analyses, and to carry out research

in connection with technique development.

X-RAY FLUORESCENCE SPECTROMETRY FOR MATERIALS ANALYSIS

Metal analysis

Research on metals being undertaken in this

Insti tute, requires rapid quantitative analy

ses. Up to the present the X-ray fluorescence

technique has largely met this need. Apart

from these services, the greatest part of the

time was spent on analytical services for

other CSIR Institutes and for industry.

Research Activities

Investigations were undertaken with the

scandium X-ray tube which had become ava i l

able as well as with the ex is t ing tungsten

X-ray tube with a view to more accurate

determination of both low and high element

concentrations in i ron- and nickel base

a l loys. The scandium target extends the

lower l im i ts of detection from 200 ppm to

100 ppm for sulphur and phosphorus and from

0 , 1 * to 0,05* for s i l i con . Binary metal

alloys were used to determine correct back

ground levels fur steels containing molyb

denum {s ign i f icant overlap from Mo L„ on

S K a l i n e ) . As a result of these techni

ques sulphur can be determined with an

average accuracy of better than 10* and

phosphorus with better than 7* at concen

t ra t ion levels of 100 to 1 000 ppm. The

depth from which fluorescent X-rays w i l l

emerae from the surface is l im i ted . Hencs,

results can be Influenced I f the sample 1s

inhomogeneous over a distance comparable

with the depth of X-ray exc i ta t ion . Thus

factors such as the metal lurgical h is tory

of the material and the type of mater ia l ,

are i ' port ant.

X - S T R A A L F L U O R E S S E N ^ I E -S P E K T R O S K O P I E

Die doel van die Seksie is om te voldoen aan

behoeftes v i r vinnige ontledings v i r die

nywerheid en WNNR-institute en om navorsing in

verband met tegniek-ontwikkeling te onderneem.

X-STRAALFLUORESSENSIE-SPEKTROMETRIE VIR NATERIAALONTLEDING

Ontleding van « t a l e

Die navorsing oor metale wat in die Ins t i tuu t

onderneem word, vereis vinnige kwantitatiewe

analises, 'n behoefte wat to t nou toe qroot-

l i k s deur die X-straalf luoressensie-tegniek

bevrediq kan word. Afgesien van hierdie

diens, het ontledingsdienste aan I ns t i t u te van

die WNI« en die nywerheid die meeste tyd in

beslag geneem.


Ondersoeke is met die skandium-X-straalbuis

wat beskikbaar geword het en met die be

st aande wolfram-X-straalbuis onderneem met

die oog op meer akkurate bepalings van so-

wel lae as hoë elementkonsentrasies in

ys te r - en nikkelbasislegerings. Die skan-

diumteiken brel die laer bepalingsgrense

u i t vanaf 200 dpm na 100 dpm v i r swae! en

fosfor en vanaf 0 , 1 * na 0,05* v i r s i l i k o n .

Binêre metaallegerings is gebruik om die

korrekte agtergrondvlakke te bepaal v i r

staalsoorte wat molibdeen bevat (betekenis-

vol le oorvleueling van Mo L„ op S Ka

l yn ) . As gevolg van hferdie tegnieke kan

swael bepaal word met 'n gemiddelde akku-

raatheld van beter as 10* en fosfor met

beter as 7* by konsentraslevlakke tussen

100 en 1 000 dpm. Die diepte vanwaar f l u o -

ressente X-strale u i t die oppervlak te

voorskyn kan tree 1s beperk. Result ate kan

dus in 'n groot mate be'fnvloed word indien

die monster nie homogeen Is oor 'n afstand

wat met die diepte van die X-straal opwek-

king vergelykbaar is nfe. Faktore soos die

metallurgiese geskledeni? van die materlaa!

en die t ipe materiaal Is dus belangrik.

S3

Mass thickness determination by wans of varying geoaetry In X-ray fluorescence spectroK-t ry

The app l icab i l i t y of the method by which X-ray

fluorescence intensi t ies of component and sub

strate elements are measured at d i f fe rent

angles to determine the mass thickness of lead

sulphide layers deposited on a glass sub

s t ra te , required fur ther invest igat ion.

Research Activities

Direct weighing of plates with and without

the layers and lead concentration determi

nation after the layers had been brought

into so lu t ion, showed very good agreement

and such layers may be used as reference

standards. A comparison of mass thickness

es obtained by the X-ray fluorescence tech

nique showed systematic deviations which

are wavelength dependent. With chromium

Ka as primary radiat ion source, unsat'

factory results were obtained when using

lead and sulphur, of which the layer is

comprised, as secondary radiat ion sources,

althouqh calcium and s i l i con in glass with

wavelengths 0,336 and 0,713 nm respective

l y , showed deviations of 12% and 24* in

comparison with the reference standards.

With scandium K0 as primary adiation

source, a deviation of 5% was found for

CaK a .

SAMPLE PREP/WAT IOH FOR X-RAY FLUORESCENCE SPECTROSCOPY

In X-ray fluorescence spectrometry sample pre

paration is a problem requir inq part icular

attention bemuse of the diverse nature of the

physical character ist ics of the samples. A

further problem is the lack of proper stan

dards with physical character is t ics simi lar to

those of the samples.

Research Activities

When the induction melting apparatus was put

into commission, part icular attention was

given to preparation techniques for non-metal

samples. A problem with geological samples

was solved by using a mixture of l i th ium

Massadiktebepaling act behulp van variërende oeoaetrie in x-straalfluoressensiespcktroae-t r i e

Die toepaslikheid van ode waardeur X-

s t raa l f luoressens ie- in tens i te i te van die same-

stellende en substraatelemente by verski l lende

hoeke gemeet word om die massadikte van lood-

sul f iedlagies wat op 'n glassubst. aat neerge-

slaan is te bepaal, noes verder ondersoek

word.

Ravorsingsaktiwiteite

Direkte weging van p laat j ies met en sonder

die lagies asook 'n konsentrasiebepaling

van lood nadat die lagies in oplossing ge-

br ing i s , toon baie goeie ooreenstemming en

sulke laqies kan as verwysingstandaarde ge-

bruik word, 'n Vergelyking van massadiktes

wat deur die X-straalfluoressensietegniek

verkry i s , toon sistematiese afwykings wat

van qolf lenqte afhanklik i s . Met chroom

K„ as primire stral ingsbron het lood en

swael, waaruit die lagie saamgestel i s ,

onbevredigende resultate as sekondêre s t ra -

lingsbronne gel ewer, alhoewel kalsium en

s i l i kon in glas met golflengtes van 0,336

en 0,713 nm respektiewelik afwykinqs van

12% en 24% teenoor die verwysinqstandaarde

qetoon het. Met skandium Kn as primêre

stral ingsbron is 'n afwyking van 5% v i r

Ca K0 gevind.

M0NSTERVOORBEREIDIN6 VIR X-STRAALFLUORESSEN-SIESPEKTROSKOPIE

Weens die uiteenlopende I'V. ie:.e eienskappe van

die monsters bly ronstervoorbtreiding 'n pro-

bleem wat besondere aandag in X-straal f luores-

sensiespektrometrie verg. 'n Verdere probleem

is die gebrek aan geskikte standaarde met d ie -

selfde f i s iese eienskappe as die van die mon

sters .

NavorsingsafctlwiteJte

Met die inbedryfste l l ing van die induksie-

smeltapparaat is veral aandag gegee ? ,.n die

voorbereidingsteqnieke v i r nie-metaal mon

sters , 'n Probleem met geologiese monsters is

opgelos deur 'n smeltmiddelmengsel van l i t i um-

54

tetraborate, l i th ium carbonate and lanthanum oxide as f l u x . Certain d i f f i c u l t i e s were experienced, v i z . temperatures reached were often not high enough for the f luxes required, cooling of some samples was too rap id , and more precise indications of temperature were required.

Special f lat-bottomed 95X Pt/5X Au dishes were acquired so that casting would not be necessary. However, e f for ts to use the modified procedure have thus far been unsuccessful because of cracking and of adhering of samples the last of which is indicat ive of some surface chemical react ion. Attention is being given to methods of overcoming these problems.

M A S S S P E C T R O S C O P Y

The aim of the Mass Spectroscopy Section is to develop methods and to provide a service for trace and u l t ra t race analysis of materials.

MASS SPECTROSCOPY OF ULTRATRACE CONCENTRATIONS IN KTALS AND ELECTRONIC MATERIALS

The spark source mass spectrograph is capable of detecting trace impurit ies in materials. Developmental work is current ly being carr ied out to optimize the quant i f icat ion procedure.

Computer controlled microphotoaeter

The interpretat ion of ion-sensit ive plates from the mass spectrograph is a d i f f i c u l t and time-consuming exercise. Computer programs and hardware have been designed to automate the process.

Research Activities

A new sy. tern to read and interpret ion plates from the spark source mass spectrograph has now been developed. Software, in both machine language and BASIC for the Zenith Z100 Microcomputer is complete. The programs allow for fully-automated reading of ion plates and subsequent o f f - l i n e processing of data using many of the sophist icated interpretat ion techniques outl ined by Franzen and Schuy1.

te t raboraat , litiumkarbonaat en lantaanoksied te gebruik. Sekere problem is egter onder-v ind , naamlik dat temperature wat bereik is dikwels nie hooq genoeg v i r die vereiste smeltmiddels was n i e , dat bepaalde monsters te v innig afqekoel het, en dat meer presiese aan-duidings van temperatuur nodig was.

In *n poging om die oorgietprosedure u i t te skakel, is qeskikte platbodembakkies van 953t Pt/5X Au verkry. Tot dusver is nog nie sukses met die gewysigde prosedure verkry nie deurdat monsters kraak en vass i t . Laasgenoem-de is 'n aanduiding van sekere oppervlak che-miese reaksies. Metodes waarvolgens hierdie probleme oorbrug kan word, word ondersoek.

H A S S A S P E K T R O S K O P I E

Die doel van die Massaspektroskopie-seksie is om metodes te ontwikkel en 'n diens te lewer v i r spoor- en ultraspoorontleding van mater i -a le .

NASSASPEKTROSKOPIE VAN ULTRASPOORKONSENTRASIES IN METALE EN &EKTRONIESE MATER I ALE

Die vonkbronmassaspektrograaf is in staat om spooronsuiwerhede in materiale waar te neem. Ontwikkelingswerk word tans onderneem om die kwantlfiseringsprosedure te optimiseer.

Refcenaarbehoerde mikrofotometer

Die interpretasie van ioonsensitiewe plate van die massaspektrograaf is moeilik en tydrowend. Rekenaarprogramme en apparatuur is ontwerp om die proses te outomatiseer.


'n Nuwe stelsel om die ioonplate van die vonkbronmassaspektrograaf te lees en in te r -preteer, is ontwikkel . Programmatuur in masjientaal en BASIC v i r die Zenith Z100-mikrorekenaar is vo l t oo i . Die programme is ontwerp v i r ten vo i le qerekenariseerde lees van ioonplate en die daaropvolqende n ie-qekoppelde dataverwerklng met gebruik van bale van die gesofistikeerde in terpretas ie-tegnieke beskryf deur Franzen en Schuy1.

5<>

The programs are designed to enable the first-time user of the system to work through the interpretation in a step-wise fashion with minimum reference to documentation. A menu-type program philosophy has been adopted to enable program flow to proceed in versatile fashion determined by the user. The system is equipped with 500 kilobytes of random access memory and full colour graphics.

Analysis of electronic Materials

Very low levels of impurities in certain materials can drastically alter their electronic properties. The mair. advantage of mass spec-trography over other analytical techniques is its sensitivity, which is essential for this type of analysis.

Research Activities

A major part of the research effort was directed towards the accurate determination of trace quantities of boron and phosphorus in silica and silicon. This research is of specific interest to the silicon manufacturing industry.

Analyses were performed using secondary standards prepared in this laboratory. An in-depth investigation was drried out on doping techniques and all standards were cross-checked with certified geological standards of similar composition. In order to determine the concentration of specific elements in an unknown sample, it is necessary to calculate sensitivity correction factors for these elements relative to an internal standard (in this case, beryllium). The atomic relative sensitivity correction factor (RSCFa) of an element X is given by

RSCFa(X) * |C(X)/C(Z)| known (C(X)/C(Z)1 apparent

where C(X) is the atomic concentration of element X

and C(Z)) is the atomic concentration of an interna! standard Z.

Die programme is ontwerp om die nuwe ge-bruiker van die sisteem in staat te stel on trapsgewys deur die interpretasie te werk met minimum verwysing na dokumentasie. 'n Nenu-programfilosofie is aanvaar sodat die program kan vloei op die wyse wat deur die gebruiker bepaal word. Die sisteem is toe-qerus met 'n 500 kilogreep ewetoeganklike geheue en volkleur grafika.

Ontleding van elektroniese «atari ale

Uiters lae onsuiwerheidkonsentrasies in sekere materiale kan die elektroniese eienskappe daarvan drasties verander. Die sensitiwiteit, wat vir hierdie tipe ontleding noodsaaklik is, is die belanqrikste voordeel van massaspektro-grafie vergeleke by ander analitiese tegnieke.

Navors ingsaktiwitei te

Die grootste gedeelte van die navorsingspo-ging was gerig op die akkurate bepaling van spoorhoeveelhede boor en fosfor in silika en silikon. Hierdie navorsing is van spe-sifiefce belang vir die siJikon-vervaar-digingsnywerheid.

Analises is uitgevoer met gebruik van se-kondére standaarde wat in hierdie laborator y voorberei is. Doteringstegnieke is deeglike ondersoek en die akkuraatheid van alle standaarde is noukeurig gekontroleer deur vergelyking met gesertifiseerde geolu-qiese standaarde met 'n soortgelyke same-stellinq. Om die konsentrasie van spesi-fieke elemente in 'n onbekende monster •-bepaal, is dit nodig om sensitiwiteitkor-reksiefaktore vir hierdie elemente teenoor 'n interne standaard (in hierdie qeval beriIlium) te bereken. Die relatiewe atoomsensitiwiteit-korreksfefaKtor (RSCFa) van 'n element X word gegee deur

RSCFa(X) * |C(X)/C(Z)| bekend |C(X)/C(Z)} skynbaar

waar C(X) die atoomkonsentrasie van element X is

en C(Z) die atoomkonsentrasie van 'n interne standaard Z is.

56

If the unknown sample is then doped with a

known amount of internal standard, relative

sensitivity correction factors can be used

to calculate the true concentrations of the

elements of interest, by correctinq their

apparent concentration measured by the mass

spectrograph. A summary of the RSCFa's

calculated from three geological standards,

doped with known amounts of beryllium, is

given in Table 1. It is apparent from

these figures that matrix composition has a

marked effect on the RSCFa's and hence it

is important to use standards very similar

in composition to the sample. The full re

sults of the investigation are given in an

internal report .

As die onbekende monster met *n bekende

hoeveelheid van 'n interne standaard gedo

teer word, kan re1 atiewe sensitiwiteit-kor-

reksiefaktore gebruik word om die ware kon-

sentrasies van elemente van belang te bere-

ken de>ir korreksie van hul skynbare konsen-

trasies wat op die massaspektrograaf gemeet

is. 'n Opsomming van die RSCFa's soos be-

reken ten opsigte van drie geologiese stan-

daarde, gedoteer met bekende hoeveelhede

beriIlium, word in Tabel 1 aangedui. Dit

blyk duidelik uit hierdie syfers dai die

matrikssamestelling 'n pertinente effek op

die RSCFa's het en gevolglik is dit belang-

rik om standaarde te gebruik waarvan die

samestelling goed met die van die monster

ooreenstem. tfolledige resultate van die

ondersoek is in 'n interne verslag2 gemeld.

TABLE/TABEL 1

Summary of Relative Sensitivity Correction Factors (RSCFa's) from Analysis of Certified Silicate Materials

Opsonin inq van Re 1 at i ewe Sensitiwiteitskorreksiefaktore (RSKFa's) met Ontleding van Silikaatmateriale

Rock typt Rotstipe

Basalt Syenite Siêniet

Granite Graniet

Standard Standaard

BCR - 1 SV - 2 SY - 3 G - 2

Specimen Monster

1 2 3 4 5 6 7 8

Be

B

Si

P

(1,0) (1,0) (1,0)

0,25 0,25 0,26

0,61 0,62 0,61

0,43 * 0,47

(1,0) (1,0) (1,0)

0,15 0,19 *

0,71 * 0,70

0,48 0,46 *

(1,0)

0,15

*

*

(1,0)

0,17

0,70

0,43

Poor data/Onbetroubare data

Specimen number Monsternommer

Description Beskrywing

Specimen number Monsternommer

Description Beskrywing

1 BCR , doped with _ gedoteer met 5 ry _ ? undoped

nie-gedoteer

2 BCR j doped with „ gedoteer met 6 ,„ _ - undoped

nie-gedoteer

3 BCR j doped with - . „ gedoteer met 7 ,y _ , undoped

nie-gedoteer

4 SY - - undoped nie-gedoteer 8 G - 2 d T ? W<th » B & gedoteer met P

S7

Scanning high resolution «ass spectrometer SkaNdecr-MéskeidiMi-aassa&pektroaetcr

A new ul t ra-hiqh resolut ion mass spectrometer

(Vacuum Generator ZA8) «as purchased ' h i s year

and is due for del ivery in July 1984. An

analysis service should be in f u l l operation

wi th in two months of i ns ta l l a t i on .

Research Activities

Certain preliminary acceptance tests were

carr ied out in England, pr ior to shipment

of the instrument to South A f r i ca . As the

primary function of the mass spectrometer

w i l l be the analysis of metals and a l loys ,

the test samples selected were N8S mi ld

steel standards. Ionization was performed

using the plasma discharge source. Results

were par t icu la r ly encouraging as the analy

sis time was considerably less than requi r

ed by spark source mass spectrography. In

addi t ion, accuracy of a few per cent was

obtained for a l l c e r t i f i e d elements in the

samples when hiqh resolut ion data was used

for ca lcu la t ion. A point worth notinq is

that isotope rat ios for such elements as

molybdenum, tungsten, chromium and iron

were accurate within IX, indicat inq that

inter-element correlat ion errors could be

due mainly to inhomoqeneity in the sample.

I f th is is the case, averaqinq of more scan

data should reduce the errors considerably.

REFURBISHMENT OF NUCLIDE MASS SPECTROMETER

A double focussinq mass rpectrometer in the

Ins t i t u te has been made operat ional. Prel im

inary results indicate that the spectrometer

has potential for inorganic and organic anal

yses.

Changes made

The Nuclide 12-90G(DF) mass spectrometer has

been in the Division for some time. Serious

faul ts existed in the vacuum system, ion

source and some of the electronic uni ts . In

Gedurende die jaar is 'n nuwe ul t rahoëskei-

ding-massaspektrometer (Vacuun- Generator ZAB)

»*• jekoop en aflewerinq is v i r Ju l ie 1984

geieel . 'n Anal i t iese diens behoort binne

twee maande n? ins ta l le r inq ten voi le te funk-

sioneer.

Hmorsiwgsaktiwiteite

Voor verskepinq na Suid-Afrika is sekere

voorlopige <>anvaardingstoetse in Engeland

op die instrument uitgevoer. Aanqesien die

primêre funksie van die massaspektrometer

die ontleding van metale en legerings sal

wees, is 'IBS saqte staal standaarde as

toetsmonsters gekies. Die plasma-ontla-

dingsbron is gebruik om ionisasie te ver-

kry . Resuitate was besonder bemoediqend

omdat die ontledingstyd aansienlik korter

was as wat met vonkbronmassaspektroqrafie

nodig i s . Voorts is daar, wanneer hoëreso-

lusiedata v i r berekeninq qebruik i s , akku-

raatheid van 'n paar persent v i r a l le

qesert i f iseerde elemente in die monsters

verkry. Dit is noemenswaardio dat isotoop-

verhoudings v i r elemente soos molibdeen,

wolfram, chroom en yster binne IX akkuraat

was. Dit dui aan dat interelement-korrela-

siefoute hoofsaaklik aan nie-homoqeniteit

in die monster te wyte kan wees. As d i t

die qeval i s , behoort foute aansienlik ver-

minder te word deur die qetniddeld van meer

skandeerdata te neero.

0PKNAPP1W» VAN NUCLIDE-MASSASPEKTROMETER

'n Dubbel-fokusserende massaspektrometer in

die Ins t i tuu t is opqeknap en in herqebruik

qeneem. Voorlopiqe resuitate dui aan dat die

spektrometer v i r beide orqaniese en anorqa-

niese analises qebruik sal kan word.

Veranderings aangebring

Die Nuclide 12-90G(DF)-massaspektrometer is

reeds 'n qeruime tyd in die Afdel inq. Daar

was ernstige defekte in die vakuumsistc<?m, die

ioonbron en sommiqe van die elektronika-een-

58

order to assess the capability of the spectrometer, a number of modifications have been made to the instrument.

• A Varian SMI electron impact ion source was f i t ted using specially designed adaptor flanges.

• A Varian power supply, interfaced to a Spellman dc power source was f i t ted to operate the ion source.

• Two new diffusion pumps have been f i t ted to the vacuum system.

Although the arrangement is unsatisfactory in some respects, it was possible to obtain a mass spectrum from the instrument and to perform alignment experiments. From a spectrum of residual gas in the mass spectrometer, the resolution was measured (m/ a n l ~2 000) and found to be sufficient for low resolution analysis.

S U R F A C E S C I E N C E

The aim of research on surface science is to evaluate the surface interface and interfacial characteristics of the materials being developed in the Institute. Studies are carried out on gallium arsenide and other semiconductor surfaces as well as on grain boundary segregation in metals.

THE ATOMIC AM) ELECTRONIC STRUCTURE OF METAL AND SEMICONDUCTOR SURFACES

Gallium arsenide surface characterization

In cooperation with the Electronic Materials Division, research has been undertaken in connection with the surface composition of gallium arsenide.

Angle-resolved X-ray photoelectron spectroscopy and Ion microprobe mass analysis have been used to establish the presence of Ga 2 0 3 , As 2 0 3 , AS2O5, GaAs03, GaAsOi,, Ga(0H)3 and As fn the oxide layer formed on gallium arsenide. This Is a preliminary step In an attempt to

hede. Ten einde die vermoé van die spektro-meter te kan skat, is 'n aantat wysigings aan die instrument aangebring.

• 'n Varian SMl-elektronbotsing-ioonbron is aangebring met gebruik van aanpassingsflen-se wat vir die doel ontwerp is .

• 'n Varian-kragbron wat deur middel van 'n tussenvlak aan "n Spellman-direkstroom-kragbron verbind is , is aangebring om die ioonbron aan te dryf.

• Twee nuwe diffusiepompe is aan die vakuum-sisteem verbind.

Hoewel die opstelling in sommige opsigte onbe-vredigend is , is di t toq moontlik om 'n massa-spektrum met die instrument te verkry en om belyningseksperimente uit te voer. Die oplos-vermoë is gemeet (m / A m ~ 2 000) met gebruik van 'n spektrum van oorblywende gas in die massa-spektrometer en dit het geblyk toerei-kend vir laeresolusie-ontledings te wees.

O P P E R V L A K W E T E N S K A P

Die doel van navorsinq op die gebied van oppervlakwetenskap is om die oppervlak- en intervlakeienskappe van die materiale wat in die Instituut ontwikkel word, te evalueer. Studies van galliumarsenied en ander halfge-leieroppervlakke, asook van korrelgrens-segre-qasie in metale word onderneem.

DIE AT00M- EN ELEKTRONIESE STRUKTUUR VAN METAAi- EN HALFGELEIEROPPERVLAKKE

Oppervlafcfcarafcterisering van galliumarsenied

In samewerklng met die Afdeling Elektronlese Materiale is navorslng ondeT.eem In verband met die oppervlaksamestelling van gallium-arsenled.

Hoek-opgeloste X-straalfotoelektronspektro-skopie en foonmfkrosonde-massa-anallse Is gebruik om die teenwoordigheid van Ga 2 0 3 , As 2 0 3 , AS2O5, GaAs03, GaAsOi,, Ga(0H)3 en As in die oksiedlaag op gallium arsenied vas te stel . Hferdle is 'n eerste stap in 'n poqinq om die

optimize the cleaning procedure for gall ium

arsenide surfaces.

Research Activities

During the year X-ray photo-electron spec

troscopy (XPS) was introduced as a surface

characterization technique to ident i fy e le

ments and the i r compounds and, together

with ion microprobe mass analysis (IMHA),

used to examine the composition of the

oxide layer formed by air oxidation on

gall ium arsenide (GaAs). This study con

s t i tu tes the i n i t i a l stage of a project

aimed at optimizing the process used for

cleaning GaAs.

Angle-resolved XPS was used to investigate

the GaAs-oxide layer at depths of 2,5 nm

and 1,2 nm. Analysis of the electronic

energy levels of Ga-3d and As-3d states

shows that a var ie ty of compounds is pres

ent but that the oxide layer has a de f in i te

s t ructure. A mult i - layer model was propos

ed in which gall ium oxide (Ga 20 3) and

arsenious oxide (AS2O3) are formed at the

GaAs-oxide interface as separate phases.

This layer is followed by a glassy phase

characterized as gall ium arsenite (GaAs03),

which is f i n a l l y followed by a layer con

s is t ing of gallium arsenate (GaAsO„) and

arsenic pentoxide (As 2 0 5 ) at the air-oxide

interface.

Gallium hydroxide (Ga(0H) 3), formed by re

action with atmospheric water vapour, as

well as elemental arsenic were also observ

ed throughout the layer.

The above .nodel was supported to a great

extent by ising the mass spectra obtained

during depth p r o f i l i n of the surface with

IMMA. These spectra show the presence of

molecular ions and !"-j ecular fraqment-ions

formed during sputtering of the surface

with argon ions. Certain ions that arise

from the surface are unequivocally derived

from specif ic compounds present in the

oxide layer allowing for iden t i f i ca t ion of

these compounds. In th is way the presence

suiweringsproses v i r gal l ium arseniedopper-

vlakke te optimiseer.

Ravorsingsafctiwiteite

Gedurende die jaar is X-st raal fotoelekt ron-

spek^roskopie (XFS) as tegniek ingevoer v i r

die iden t i f i se r ing van elemente en hul le

verbindinqs en, tesame met ioonmikrosonde-

massaanalise (IMHA), gebruik om die same-

s te l l i ng ân die oksiedlaag wat deur lug-

oksidasie op gall iunarsenied (GaAs) gevorm

word, te ondersoek. Hierdie ondersoek is

die eerste fase van 'n projek wat gerig is

op optimisering van die proses wat in die

suiwering van GaAs sebruik word.

Hoek-opgeloste XFS is gebruik om die GaAs-

oksiedlaag by dieptes van 2,5 nm en 1,2 nm

te ondersoek. Analise van die e lekt ron-

energie-vlakke van Ga-3d- en As-3d-toestan-

de toon dat 'n versktidenheid verbindings

in die oksiedlaag teenwoordig i s , maar dat

die laag toq 'n bepaalde struktuur het. 'n

Muttilaaq-model is voorgestel waar gal l ium-

oksied (Ga 20 3) en arseentrioksied (As 20 3)

by die GaAs-oksied-tussenlaag as aparte

fases qevorm word. Die' laag word gevolg

deur 'n glasagtige fase wat as gal l ium

arseniet (GaAs03) gekarakteriseer is en wat

f inaal bedek word deur 'n laag wat u i t gal -

liumarsenaat (GaAsOi.) en arseenpentoksied

(AsÔ^) bestaan.

Galliumhidroksied (Ga(0H) 3), wat deur reak-

sie met atmosferiese waterdamp gevorm i s ,

sowel as elementêre arseen is 00k dwarsdeur

die oksiedlaag waargeneem.

Die model hierbo beskryf is in 'n groot

mate beaam deur die gebruik van massaspek-

t r a , wat met behulp van IMMA tydem diepte-

p ro f i l e r i ng van die oppervlak verkry i s .

Hierdie spektra toon die teenwoordiqheid

van molekulêre ione en molekulêre fraqment-

ione wat gedurende verstuiwinq met arqon-

ione qevorm word. Sekere ione wat u i t die

oppervlak afkomstig i s , kan met 'n qroot

mate van sekerheid aan bepaalde verbindinqs

qekoppel word wat dus ident i f ikasie van die

of Ga(0H)3 and elemental arsenic observed

during the XPS invest igat ion was confirmed.

THE CHEMICAL COMPOSITION OF SURFACE NJCRO-STRUCTURES OF ALLOYS AND ELECTRONIC DEVICES

Chroai» depth profi le through epitaxial gallium arsenide layer

In cooperation with the Electronic Materials

Div is ion, ion microprobe mass analysis was

used to determine the chromium concentration

p ro f i l e in a gallium arsenide epi layer.

Research Activities

Ion microprobe mass analysis has been used

to check the qual i ty of an epilayer of

GaAs. on a semi-insulating Cr-doped GaAs

substrate grown at the University of Port

El izabeth. Cr and C pro f i l es across the

layer into the substrate are given in F iq .

15. A de f in i te Cr concentration gradient

is observed up to a depth of about 1 urn,

which is the estimated depth of the ep i

layer. This is then followed by a constant

concentration into the substrate. I t is

thus clear that the doping material d i f f us

es from the substrate into the epi layer.

The C p ro f i l e appears to be constant across

both the epilayer and the substrate showing

good cleaning of the substrate before ep i

tax ia l growth.

This study has been completed.

Improvements to ion «icroprobe mass analyser ( I H » )

A tr iangular waveform generator has been b u i l t

for primary ion-beam scanning in the ARL IMMA

as an al ternat ive to the ex is t ing sawtooth

waveform generator. The advantage of the t r i

angular waveform is that the nonlinear t r ans i

ents associated with the fast fly-back of the

sawtooth waveform are eliminated and that the

actual voltages applied to the sweep plates

fol low the driver siqnal from the waveform

generator more accurately. This results in a

much more uniform sputtering action over the

verbindings toelaat. Op die wyse is die

teenwoordiqheid van Ga(0H)3 en elementêre

arseen, soos gedurende die XFS-ondersoek

waargeneem, bevestig.

DIE CMENIESE SMESTELLIR6 VAN MUtOSTRUKTURE VAN LEGERIRSS EN ELEKTRONIESE TOESTELLE

Chrooa-diepteprofiel dear epitaksiéle gall iaa arseniedlaag

In samewerking met die Afdeling Elektroniese

Materiale is ioonmikrosonde-massa-analise ge-

bruik om die chroomkonsentr«iiep»ofiel in 'n

epilaag galliumarsenied vas te i t e l .

NavorsiiMjsaktiwiteite

Ioonmikrosonde-massa-analise is qebruik om

die kwa l i t e i t te bepaal tan 'n epilaag GaAs

wat op 'n semi-isolerende substraat van Cr-

gedoteerde GaAs by die Univers i te i t van

Port Elizabeth gegroei i s . Figuur 15 toon

Cr- en C-prof ie le deur die laag tot in die

substraat. 'n Definit iewe konsentrasie-

gradiënt word in die Cr-prof ie l tot by 'n

diepte van ongeveer 1 um wa,. qeneem, wat

die geskatte diepte van die epilaag i s .

Die gradient word qevolg deur 'n konstante

Cr-konsent.-asie in die substraat. Dit is

dus duidel ik dat Cr u i t die substraat na

die epilaag diffundeer. Die C-prof iel blyk

konstant te wees in beide die epilaag en

die substraat, wat op goeie re in ig ing van

die substraatoppervlak du i .

Hierdie studie is vo l too i .

Verbetering van ioonmlkrosonde-massa-anali-seerder (IMMA)

'n Dr1ehoekgolfontw1kkelaar is v i r die skande-

rfng van die primêre ioonbundel van die ARL-

IHMA gebou as 'n a l te rnat ie f v i r d ie huidige

saagtandgolfontwikkelaar. Die voordeel van

die driehoekige golfvorm is dat die n ie-

l ineêre oorgange wat met die vinnige terugslaq

van die saaqtandvorm geassosieer word, u i tge-

skakel word en dat die werkl ike spanninq op

die skandeerplate die dryfsein vanaf die ont-

wfkkelaar meer akkuraat volg. Dit le i tot 'n

bale meer eenvormiqe verstuiwing oor die hele

61

DEPTH (.a) DIEPTE (,.nl

m a

375. •

«.•

•

•

*

* * • • • • • * • • • •

* * * » • * . * * * « \

&f^*

t I SPUTTERING TIME, s VERSTUIWINGSTVO. s

FIGURE/FIGUUR 15:

Chromium and carbon depth pro f i les through gall ium arsenide epi iayer

Chroom en koolstof d iepte-prof ie le deur qalliumarsenied epilaag

ent i re scanned area and in the elimination of

edge grooving normally observed with the saw

tooth waveform.

The or ig ina l analogue squarer for mass scale

l inear izat ion in the IMHA has been replaced by

a programmable d i g i t a l squarer system which

permits re l iab le mass number ident i f i ca t ion

throughout the tested range of 1 lo 240. The

d ig i t a l squarer provides signals to both a

d ig i t a l direct reading mass number display and

to an X-Y recorder where i t provides a l inear

mass scale correct to within 0,3 mass uni ts .

An addit ional output can be coupled to a com-

puter.

geskandeerde oppervlak en die verwydering van

groewe wat gewoonlik met 'n saagtandvorm op

die kante van die krater sigbaar i s .

Die oorspronklike analoogkwadreerder v i r mas-

saskaal- l ineêrisasie in die IMMA is deur 'n

proqrammeerbare syferkwadreerder vervang wat

die akkurate bepalinq van massagetal toelaat

soos getoets vanaf 1 to 240. Die syferkwa

dreerder voorsien seine aan beide 'n syferver-

toonbeeld en 'n X-Y-registreerder waar d i t 'n

l ineêre massaskaal akkuraat tot binne 0,3

massa-eenhede verskaf. 'n Bykomstige eenheid

kan ook aan 'n rekenaar gekoppel word.

The modifications required to improve th is in

strument have been completed.

Die veranderinge wat nodig was om hierdie i n

strument te verbeter, is afqehandel.

E L E C T R O N M I C R O S C O P Y E L E K T R O N M I K R O S K O P I E

The aim of research in electron microscopy is

to generate expertise in the application of

Die doel van navorsing oor elektronmikroskopie

is die ontwikkeling van kundigheid by die toe-

62

t h i s technique to m a t e r i a l s - r e l a t e d problems.

S t ' d i e s on e l e c t r o n d i f f r a c t ' c , a n a l y t i c a l

techniques in e l e c t r o n in icropivbe a p p l i c a t i o n ,

e l e c t r o n d e t e c t i o n systems, and d i s l o c a t i o n s

in deformed metals ire t h e r e f o r e under taken.

passing van d i e teqniek op mater i aalverwante

probleme. **et h i e r q j e doel voor oe word s t u

d ies oor e l e k t r o n d i f f r a k s i e , ont l e d i n q s t e g -

nieke by die toepass inq van die e l e k t r o n m i k r o -

sonde, e lek t ronwaarneminqs is teme, en o n t w r i g -

t i n q s in vervormde met a le onderneem.

ADVANCED TECHNIQUES IN ELECTRON MICROSCOPY AND ELECTRON OIFFRACTION

GEVORDERDE TEGNIEKE IN ELEKTRONMIKROSKOPIE EN ELEKTRONDIFFkAKSIE

Convergent beam e l e c t r o n d i f f r a c t i o n (CBD)

permi ts s tud ies i n v o l v i n o o r i e n t a t i o n measure

ment, r e l a t i v e l a t t i c e parameter de te rm ina t i on

and symmetry chanqes to be c a r r i e d out w i t h a

h iqh p r e c i s i o n from ext remely l o c a l i z e d

a r e a s ' . This i s due p r i m a r i l y t o the small

e l e c t r o n probe s izes invo lved and the s e n s i t i

v i t y of the technique to th ree-d imens iona l

d i f f r a c t i o n e f f e c t s , q i v i n q r i s e to r i ngs of

i n t e n s i t y known as h iuher order Laue zone

( h o l z ) r i n q s , as shown in F i q . 16.

' J i t e rs no ike^r-iqp st id ies wat be t r ekk i nq het

Op o r i e n t a^ ie - ' i ' e t i nqs , die bepal inq van r e l a

t i one i '0 .osr . ' ( -p i ra: iv ters, en s i iT ie t r i e - ve rande -

r i n q s kan «an JUÍtenqewoon qe loka l i see rde

areas deur konverqente bundel - e l e k t r o n d i f f r a k -

s i e (CBf) orulernee'T w o r d 1 . D't is hoo f saak l i k

t e wyte ian d ie k l e i n e l e k t ronsondeqroot tes

daarby b e t ' v u k e en die qevon 1 iqne id van d i e

teqniek v i r or j f-fl iiiiens i onel e d i f f raks i e - e f f e k -

te wat i n t e n s i t e i t s r i n q e , bekend as hoër orde

1 a i ié -snne- ' inqe ( h o l z - r inqe ) , t o t qevolq het

snos in z i i ; . 16 aanqetoon.

F Ifil'RF /F rri'itlR In:

Convergent heart' u l e r f r n n d i f f rar t inn p a t t e r n . : f ? M ( ^ Í I ' ; ; taken ^t )•)() 'fí.y

Konvprqent.e bunde l -c lek t r n n d i f f raks i-nat roon van ^'itiMr,',, *].•:•..;•!!• by 1'tn t u j

Research Ac t i v i t i es Ravorsiagsaktiwiteite

Over the past year, considerable success has

been achieved in both the application and de

velopment of the CBO technique with regard to

defect characterisation in c rys ta l l i ne so i ids .

Of par t icu lar interest has been the study of

planar stacking f au l t s , such as those found in

layer structures, which are d i f f i c u l t to char

acter ize using conventional methods. A theore

t i c a l model has been developed which explains

the apparent s p l i t t i n q of holz r ings , permit

t i ng the derivation of st ructural information

re la t ing to the faul t 1 * . In addi t ion, studies

have been successfully concluded involving a

theoret ical interpretat ion of the symmetry

changes in CBO patterns as well as the devel

opment of a pract ical technique for the meas

urement of sample thickness from faul ted

regions.

New sti.'dies re la t ing to the structure re f ine

ment of materials ( i . ? . the accurate determi

nation of atomic posit ions) have recently been

implemented. The development and application

of large-angle CBO methods have been of p a r t i

cular benefit to th is area of research, enabl

ing holz f ine structure to be examined in de

t a i l . In addi t ion, a considerable e f fo r t has

been made to establish the essential theoret

ical background required to interpret the re

sul ts of these techniques. This has involved

the development and ins ta l la t ion of computer

software coupled with investigations of a more

i n t u i t i v e nature, allowing analyt ical ap

proaches to be pursued in specif ic areas of

theoret ical electron d i f f r ac t i on .

Cooperative projects have been established

with other Divisions within the NIMR which are

pa r t i cu la r l y concerned with the applications

of CBO. These studies involve

• an analysis of res t r ic t ions placed on spe

cimen thickness determination in layer

structures using CBD methods.

• a theoretical discussion of factors a f fec t

ing holz l ine intensi t ies *.i microst iuctur-

al studies.

Gedurende die afgelope jaar is aansienlike

sukses, met beide die toepassing en die ont-

wikkeling van die CBO-tegniek, in verband met

defekkarakterisering in k r i s ta l l yne vaste

stowwe behaal. Van besondere belang is die

studie van planêre stapel foute, byvoorbeeld

die wat in laagstrufcture voorkom, wat moeil ik

met konvensionele metodes karakteriseerbaar

i s . "n Teoretiese model is ontwikkel wat die

skynbare sp l i t s i ng van holz-r inge verklaar en

wat dan die af le id :ng van s t ruk tuu r - i n l i g t i ng

in verband met die fout moontlik maak1'. Voorts

is studies gemoeid met 'n teoret iese v?rk la-

r ing van die simmetrie-veranderings in CBO-

p at rone en met die ontwikkel ing van 'n prak-

t iese tegniek v i r die meting van mons'erdikte

van stapelfoutomgewings, suksesvol afgehandel.

Nuwe ondersoeke in verband met die struktuur-

verfyning van materiale (byvoorbeeld die akku-

rate vasste l l ing van atoomposisies) het on-

lanqs 'n aanvanq geneem. Die ontwikkeling en

toepassing van groothoek-CBD-metodes het be

sondere voordele v i r h ierdie navorsingsgebied

ingehou aanqesien holz-fynstruktuur in beson-

derhede ondersoek kan word. Oaarbenewens is

'n deeglike poqing aangewend om die teoretiese

agtergrond wat v i r die interpretasie van

resul tate van hierdie teqnieke noodsaaklik i s ,

te verkry. Oit het die ontwikkelinq en i n s t a l -

ler ing van programmatuur tesame met ondersoeke

van 'n meer intuTtiewe aard behels waardeur

anal i t iese benaderings v i r bepaalde areas van

teoretiese e lek t rond i f f raks ie moontlik gemaak

i s .

Projekte in samewerking met ander NIMN-afde-

l ings wat veral met die toepassinqs van CBD

gemoeid i s , is g e v s t i g . Hierdie studies han-

del oor

'n ontleding van beperkinqs op monster -

dikte-bepalinq in laagstr jk ture deur tniddel

van CBO-metodes.

'n teoretiese besprekinq van faktore wat

ho lz - l yn in tens i te i te in mikrostruktuurstu-

dies beTnvloed.

64

DISLOCATIONS I I I SURFACE PLASTICITY EFFECTS A » FATIGUE I I METALS

(MTMRICTIRSS IN OPPCRVLAKPLASTISITEITSEFFEKTE EM VERPKIONEIO IN NETALE

Studies on the soft surface effect in poly-crystalline copper have been undertaken as an extension of previous work on copper sin le crystals.

Research Activities

Preliminary results on electrolytically sectioned crystals indicate that there is a soft Surface effect but that i t is considerably smaller than for single crystals. This result corresponds with previously held views that the effect would penetrate into the crystal to the extent of a few grain diameters. Further tensile tests and transmission electron microscopy studies are in progress.

Related studies in fatigue with particular reference to plastic instabil i ty on stress reversal are being undertaken. The f i r s t design of a suitable fatique cage has been completed and preparation of the final machine drawings is in progress.

DEVELOPMENT OF ANALYTICAL TECHNIQUES IN ELECTRON mCROPROBES

Electron probe microanalysis of samples containing elements from sodium upwards in the atomic scale is an established technique which has been used extensively for the last two decades and more, by geologists for example. Because of its abi l i ty to make accurate analyses of particles a few microns in diameter, i t is also an essential tool in the f ie ld of materials development.

Research Activities

Following the commissioning of the JEOL 733 microprobe analyser, work carried out during the current year has varied from routine examination of samples for the distribution of minor elements (~O,01 mass t) to the most precise measurement of element concentrations which can be achieved with the technique. An

Vorige werk oor koper enkelkristalle is uitge-brei om studies oor die sagte-oppervlakeffek in polikristallyne koper in te s lu i t .

Navorsiiwjsaktitriteite

Voorlopige resultate in verband net kr istal le wat elektroli t ies deurgesny is , dui aan dat daar *n sagte-oppervlakeffek is, maar dat d i t aansienlik kleine- as vir enkelkristalle is. Hierdie resultaat stem ooreen met vorige menings dat die effek tot die mate van 'n paar korreldeursneë in die kristal sou indring. Daar word voortgegaan m?t verdere trektoetse en transmissie-elektronmikroskopiestudies.

Verwante studies oor vermoeidheid met beson-dere verwysing na plastiese onstabiliteit met spanningsomkering word onderneem. Die eerste ontwerp vir 'n geskikte vermoeidheidshok is voltooi en die finale masjientekeninge word voorberei.

ORTMIKKELING VAN ANALITIESE ELEKTRORMIKRO-S0NDE-TE6NIEKE

Elektronmikrosonde-ontleding van monsters wat elemente vanaf natrium en hoe'r op die atoom-skaal bevdt, is 'n erkende teqniek wat reeds vir meer as twee dekades uitgebrei en toeqe-pas i s , byvoorbeeld deur geoloë. Weens die vermoë om akkurate analises van deeltjies met 'n deursnee van 'n paar mikron te maak, is dit ook 'n noodsaaklike hulpmiddel op die gebied van materiaalontwikkeling.


Nadat die JEOL 733 mikrosonde-analiseerder in bedryf geste! is , het werk die afgelope jaar gewissel van die roetine ondersoek van monsters om die verspreiding van newe-elemente (~0,01 massa X) vas te ste l , tot die noukeu-rigste meting van elementkonsentrasies wat met die teqniek bereik kan word, 'n Voorbeeld van

example of the la t te r is the measurement of cadmium in cadmium mercury t e l l u r i d e . In order to monitor the expected electronic properties of th is semiconductor material at an early stage of device production, i t is necessary to measure the cadmium concentration with a re la t ive accuracy approachinq IX. A p rec i sion of 0.6X re la t ive has been achieved in the current year through attention to c r i t i c a l aspects of instrument s t a b i l i t y , but further work is required to prove the accuracy of the analyses.

laasqenoemde is die bepaling van kadmium in kadmium kwik t e l l u r i e d . Ten einde die verwagte elektroniese eienskappe van h ierd ie hal fge-leiermaterfaal op 'n vroeë stadium van toe-stelvervaardiging t e monitor, is ciit nodig om die kadmiumkonsentrasie met 'n relat iewe akku-raatheid van ongeveer IX te bepaal. 'n Relatiewe noukeurigheid van 0,6% is gedurende die jaar bereik deur aandag aan k r i t i e se aspekte van ins t rument -s tab i l i te i t t e gee. Verdere werk is egter nodig om die akkuraatheid van die ontledinqs te bewys.

An unusual application of microprobe analysis is *he measurement of concentrations of t!ie l ight elements boron, carbon, nitrogen and oxygen in samples. The low energy X-ray photons generated by atoms at this end of the atomic scale are subject to severe absorption by the sample matrix and the calculat ion of absor/tion corrections is a process of uncertain accuracy. A research programme designed i n i t i a l l y to test the value of the current ly available absorption correction programmes is in hand and the f i r s t results on carbide prec ip i tates in white cast irons are sat is factory.

'n Buitengewone toepassing van mikrosonie-ont-leding is die meting van konsentrasies van die l i q t e elemente boor, kools to f , s t i ks to f en suurstof in monsters. Die lae-energie X-slraalfotone wat deur atome op nierdie end van die atoomskaal vrygestel word, is onderworpe aan 'n ernstige mate van absorpsie deur die monstermatriks en die akkuraatheid van die berekeningproses van absorpsiekorreksie is onseker. 'n Navorsingsprogram wat aanvanklik ontwerp is om die waarde van die absorpsiekor-reksieproqramme wat tans beskikbaar is te toets, is aan die gang en die eerste resul tate in verband met karbied-presipi tate in w i tg ie t -ystersoorte is bevredigend.

E L E C T R O N I C D E V E L O P M E N T A N D A U T O M A T I O N

E L E K T R O N I E S E O N T W I K K E -L I N 6 E N O U T O M A T I S A S I E

The main concern of the Electronics Section is the development of computer-controlled measuring techniques for various projects. The sect ion is also responsible for a l l other electronic instrumentation as well as for the maintenance involved.

Die Elektronika-seksit ontwikkel veral reke-naarbeheerde meettegnieke v i r 'n aantal pro-jek te . Die seksie is ook verantwoordelik v i r a l le ander elektroniese instrumentasie en die gepaardqaande instandhouding.

ELECTRONIC 0ESI6N AND DEVELOPMENT IN CONTROL AND DATA COLLECTION SYSTEMS

ELEKTRONIESE ONTWERP EN ONTWIKKEL ING IN BEHEER- EN DATAVERSfAELINGSTELSELS

This project is closely linked to the requirements of otr.'.-r projects, especially atomic spectroscopy, where electronic development and maintenance are required. Since the Divis ion has a large number of sophisticated surface scanning analytical instruments, the Electronic Section w i l l also become more involved in the maintenance and operation of of these i n struments.

Die projek is nou verbonde aan die behoeftes van ander projekte, veral atoomspektroskople, waar elektronieoe ontwikkeling en instandhouding nodig I s . Aangesien die Afdeling oor 'n hele aantal gesofistlkeerde oppervlakskande-rende anaHtlese instrumente beskik, sal die Elektronlka-seksie ook meer betrokke raak by die Instandhouding en bedryf hiervan.

66

Research Activities NworslngsaktiwHeite

Work in connection with the fol lowing has been

completed.

• Paschen-Runge spectrometer - A 24-channel computer-control led measurement system has been set up.

• A new 16-bit microcomputer with 10 megabyte disk was linked to the microphotometer.

• A s i x -po r t , 16 channel interface for an S-100 bus was constructed. Such an interface wa.; sent to t i e Computer Science Department of the University of Port Elizabeth fo r evaluat ion.

• A d i g i t a l squarer was bu i l t and ins ta l led

in the ion microprobe mass analyser.

New and continuing ac t i v i t i es include the f o l lowing:

The Polychromator:

• A l i th ium f luor ide disc, mounted on top of a small step-motor was insta l led behind the entrance s l i t . One motor step rotates the disc through 0,36 deqrees. This rotat ion corresponds to a displacement of 0,06 nm in the spectrum. Rotation of the disc enables scanning of l ine peaks and l ine background regions after the exi t s l i t s have beer, posit ioned.

• A serious problem with high voltage elect r i c a l discharges at pressures in the spectrometer in the region of 1 x 10" 2 mbar was encountered in the photomult ipl ier bases. The problem was solved by rebuilding these bases and mouldinq them in a suitable epoxy.

• To accommodate more exit s l i t s in the u l t rav io le t region, four t ro l l eys were r e designed to support photofliultipHers with

Die volqende werksaamhede is afgehandel.

• Paschen-Runge-spektrometer - 'n Rekenaarbe-

heerde 24-kar.aal meetsisteem is opgestel.

• 'n Nuwe lS-bis-mikrorekenaar met 'n 10-megagreepskyf is aan die mikrofotometer gekoppel.

• 'n Sespoort 16-parallel le-kanaal-koppelvlak v i r 'n S-100-bus is v o l t o o i . Een so 'n kop-pelvlak is aan die Afdeling Rekenaarweten-skap, Univers i te i t van Port Elizabeth v i r evaluasie gestuur.

• 'n Syferkwadreerder is ontwikkel en in die ioonmikrosonde-massa-analiseerder ge ins ta l -leer .

Voortgesette en nuwe werksaamhede s l u i t die

volgende i n :

Die Polichromator:

• 'n L i t iumf luor iedskyf ie wat op *n stap-motort.iie gemonteer i s , is agter die intreespleet ge'fnstalleer. Een stap van die motor roteer die skyf ie deur 'n hoek van 0,36 grade Die rotasie stem ooreen met 'n verskuiwing van 0,06 nm in die spektrum. Rotasie van die skyf maak d i t moontlik om lynagtergrond areas en lyn-pieke te skandeer nadat die u i t t reesp le te in posisie geklamp i s .

'n Ernstige probleem met elektr iese hocq-spanningontladinqs in die fotovermenigvul-digerbasisse is in die spektrometer by druk in die omgewing van 1 x 10" 2 mbar on-dervind . Die probleem is oorbrug deur die buissokke oor te bou en in 'n geskikte epoksie te g ie t .

• Ten einde meer u i t t reesp le te in die u l t r a -violetgebied te kan huisves, is v ier t r o l l ies herontwerp om fotovermenigvuldlger-

67

side windows behind the exit s l i t s . These

changes are nearly complete.

• Software programs are being deve'"ped to create a spectral data base for the 160 nm - 480 nm region of the plow discharge spectrum.

The development of a new microphotometer has had a low priority up to the present. The optical system is now being developed. The drive mechanism for the photoplate holder has been completed. The plate holder is displaced in steps of 0,25 urn at a rate or' 20 000 steps per second.

A new microcomputer is at present being interfaced to an X-ray photoelectron spectrometer.

An electronic workstudy group has been formed to promote good communication between electronics sections within the Institute (SMAT 17).

1 . K D Schuy & J Franzen, Fresenius Z. Anal. Chem., 225 (1967) 260.

2. D E C Rogers, 0 S Jones, J W Wegiran, L Brain 6 A C van Wamelen, IMAT 10 (November 1983)

3. Introduction to Analytical Electron Microscopy, eds. J J Hren, J I Goldstein & D C Joy, (Plenum, New York, 1980) p 387.

4. D E Jesson, Proc. Electron Microsc. Soc. South. A., 13 (1983) 33,

68

buise te steun deur syvensters vertikaal agter die uittreesplete te monteer. Hierdie veranderinge is byfcans voltooi.

• Die nodige programmatuur vir die skepping van 'n spektrale databasis vanaf 160 nm tot 480 nm in die gloei-ontladingspektrum word tans ontwikkel.

Die ontwikkeling van 'n nuwe mikrofotometer het tot dusver 'n lae voorrang geniet. Die optiese sisteem word tans gebou en die aan-dryfmeganisme vir die fotoplaathouer is vol-tooi. Die fotoplaathouer word in stappe van 0,25 urn beweeg teen 'n tempo van 20 000 stappe per sekonde.

'n Nuwe mikrorekenaar word tans aan 'n X-straalfotoëlektronspektrometer gekoppel.

'n Elektroniese werkstudiegroep is saamgestel om kommunikasie tussen die elektronikagroepe in die Instituut te bevorder (SMAT 17).

The aim of the Metals Division is to develop the physical metallurgical research base and its application to materials enqineerinq. The research infrastructure continues to place a strong emphasis on the fundamental understanding of the mechanical, physical and chemical properties of metals and alloys in terms of their microstructure and its dependence on processing parameters.

The research and development proqramme is fo-cussed on new alloys, the development of surface treatments and coatings, high-technology or novel metallurgical processing routes as well as advanced studies of r.iechanical behaviour, both for bulk materials and surface properties, all designed with specific longer-term engineer'nq roles or Siuth African requirements and raw materials in mind.

The divisional activities are divided into six research projects and five major sponsored contracts, the former being:

• Alloy development

• Surface treatments and coatinqs • Heat-resistant alloys

• Mechanical behaviour of metals and alloys • Ducti le iron • Surface mechanical properties of metals.

K E T K L E

N R Cnmins Head of Divis ion / Afdelinqshoof

Die doel van die Afdelinq is om 'n f i s iese metallurgiese navorsinqsbasis en die toepas-sinq daarvan op materiaalingenieurswese te ontwikkel. Die navorsinginfrastruktuur laat steeds sterk klem val op die fundamentele be-gr ip van die meganiese, f i s iese en chemiese eienskappe van metale en legerings in terme van die mikrostruktuur en die afhanklikheid daarvan op verwerkingsparameters.

Die navorsings- en ontwikkelinqsprogram is ge-mik op nuwe leqerings, die ontwikkeling van oppervl akbehandel inqs en -bedekkings, hoé'-tegnologiese of nuwe metallurgiese verwer-kingsroetes asook gevorderde ondersoeke na meganiese gedrag vir beide volumemateriale en oppervlakeienskappe, alles met die oog op spesifieke langtermyn ingenieursgebruike of Suid-Afrikaanse behoeftes en grondstowwe.

Bedrywighede in die Afdeling word verdeel in

ses navorsingsprojekte en vyf belangrike ge-

borgde kontrakte. Die navorsingsprojekte i s :

• Legeringontwikkeling

• Oppervl akbehandel ings en -bedekkinqs

• Hittebestande leqerinqs • Meqjniese gedraq van metale en leqerings • Rekbare yster • Oppervlak-megar iese eienskappe van metale.

69

A L L O Y D E V E L O P M E N T L E G E R I N 6 0 N T M I K K E L I N G

The al loy development proqramne of research, together with i t s accompanying contract proj e c t s , consists of a number of separate topics which a l l have the i r or ig ins in current industry-based problems and which also a l l derive from a common need to make the best of ferrous materials ei ther used by, or the product o f , the mining industry.

The subdivisions of the project address d i f ferent application areas as fo l lows:

• the study of molybdenum-free medium carbon low-alloy s tee ls , with par t icu lar emphasis on hardenabi l i ty.

• the development of lower cost stainless

steels, e.g. Fe-Mn-Al a l loys.

• white cast iron development for abrasion-

resistant appl icat ions, with special a t ten

t ion to a l loy design and novel processing

technology.

In addition the project team is current ly contracted to the extent of three man-years of research staf f time spec i f i ca l l y to undertake al loy development work for industry. This development has arisen predominantly from expertise qained from present and previous research programmes.

Research Activities

MOLVBOEMJM-FREE MEDIUM CARBON STEELS

Molybdenum is known to have beneficial ef fects in low-alloy steels on hardenabi l i ty , res is tance to temper softeninq and temper embrit-tlement. For reasons of both cost and the lack of a local resource, however, i t should also be regarded as an element of strategic importance to South A f r i ca . ' I t is thus Important to seek other elements or combinations of elements as substi tutes for molybdenum, giving comparable or superior performance in a l l the «•hove aspects.

Die navorsingsprogram v i r die legeringontwik-kelingsprojek en die meeqaande kontrakprojek-te bestaan u i t 'n aantal afsonderlike onder-werpe wat almal u i t huidige probleme in die nywerheid voortspruit en wat almal ontstaan as gevolg van 'n algemene behoefte om yster-materiale wat deur die mynwese benut of gepro-duseer word ten beste te gebruik.

Die onderafdelings van die projek behandel die onderskeie toepassingsgebiede as volg:

• die ondersoek van molibdeenvry medium-kool-stof lae- leger inq-staalsoorte, met beson-dere klem op verhardbaarheid.

• die ontwikkeling van goedkoper vlekvry

s taalsoor te, bv. die Fe-Mn-Al legerings.

• die ontwikkelinq van wi tq ietyster v i r skuurbestande toepassings met spesiale aan-daq aan die legeringontwerp en nuwe ver-werkingstegnologie.

Die projekspan is tans ook v i r dr ie man-jare van navorsingspersoneel se tyd onder kontrak om legerinqontwikkelingswerk v i r die nywerheid te onderneem. Hierdie ontwikkelinq spruit hoofsaaklik voort u i t kundiqheid wat u i t hu i dige en vorige navorsingsprogramme opgetou i s .

Havorsingsaktiwitelte

MOLIBDEENVRY MIDIUM-K0OLST0F STAALSOORTE

Molibdeen is bekend v i r 'n qunstige uitwerking op verhardbaarheid en weerstand teen temper-versagting en -verbrossing in lae- leger ing-staalsoorte. Weens die koste en die gebrek aan 'n plaasl ike verskaffinqsbron behoort d i t egter ook as 'n element van strategiese belang v i r Suid-Afrika beskou te word. Dit is dus belanqrik om ander elemente of kombinasies van elemente te soek wat as plaasvervangers v i r molibdeen dieselfde of beter werkverriqt inq in al die bogemelde aspekte sal qee.

70

In the previous report, the development of the alloys Bm (EN18 • boron + rare earth metals) and BVM (ENI8 • boron • vanadium • rare earth metals) with their excellent hardenability behaviour was discussed. More recently experiments have been conducted to study other aspects of these and related alloys, including BV (EN18 • boron + vanadium) which shows equivalent hardenability to BMM. A simple heat treatment procedure was performed to determine the resistance of these alloys to temper softening in terms of the time needed at a tempering temperature of 650 °C to reach a hardness of HRC 30, all samples being austenitized at 900 °C . The results, shown in Table 2, indicate that the vanadium steel shows better resistance than even the molybdenum-containing EN19, but that rare earth metal additions have no beneficial effect.

Die ontwikkeling van die legerings BMM (EN18 • boor • seldsameaarde-metale) en BVM (EN18 + boor • vanadium • seldsameaarde-wetale) en hulle uitstekende verhardbaarheidsvermoë is in die vorige verslag bespreek. Meer onlanqs is eksperimente uitgevoer om ander aspekte van hierdie en verwante legerinqs te ondersoek, insluitende BV (EN18 + boor + vanadium), wat 'n verhardbaarheidsvermoë gelykstaande aan die van BMM toon, 'n Eenvoudige hittebehandelings-prosedure is uitgevoer om die weerstand van hierdie legerings teen temperversagting te be-paal in terme van die tyd wat by 'n temper-temperatuur van 650 °C nodig is om 'n hardheid van HRC 30 te bereik, as alle monsters by 900 °C geaustinitiseer word. Die resultate in Tabel 2 dui daarop dat die vanadiumstaal 'n hoër weerstand as selfs die molibdeenbevatten-de EN19 toon, maar dat byvoegings van seldsameaarde-metale geen voordelige uitwerking het nie.

TABLE/TABEL 2

Temper softening and temper embrittlement characteristics of experimental alloys

Temperversagting- en temperverbrossingseienskappe van eksperimentele leqerings

Alloy Time to reach HR C 30 (hours) FATT (°C) Legering Tydsverloop om HR C 30 te bereik (ure) BVOT (°C) EN18 0,5 -6 EN18 + B 0,5 -28 EN19 4 -50 BIW 1 -45 BV 6 -10

In order to study the resistance to temper em-brittlement, the alloys were tempered to a hardness of HRC 30 and then submitted to a harsh eifcrittlement treatment. The fracture appearance transition temperature (FATT) was then determined, as is also shown in Table 2. The addition of rare earth metals clearly improve:, the temper embrittlement characterist ics, but vanadium leads to a deterioration (compare EN18 + 8 with alloy BV). Temper embrittlement work on the BVM-series is s t i l l in progress.

Ten einde die weerstand teen temperverbrossing te ondersoek, is die leoerings tot 'n hardheid van HRC 30 qetemper en is toe aan 'n ruwe verbrossingsbehandeling blootgestel. Die breukvoorkoms-oorgangstemperatuur (BVOT) is toe bepaal, soos ook in Tabel 2 aangedui word. Die byvoeging van seldsameaarde-metale ver-beter duidelik die temperverbrossingteienskap-pe, maar vanadium lei tot 'n verswakkinq (verge lyk EN18 • B met legerinq BV). Temperver-brossingsondersoeke op die BVM-reeks is nog aan die gang.

I t may be concluded that the series of alloys developed shows not only promising hardenability behaviour suitable for substituting alloys

Die gevolgtrekking kan gemaak word dat die reeks legerings wat ontwikkel is belowende verhardbaarheidsgedrag toon, wat geskik is om

71

from EN19 to EN24, but also satisfactory resistance to temper softening and temper em-brittlement.

legerings wan EN19 tot EN24 te vervang, en daarmee saam bevredigende weer stand teen tern-pervert aq ting en temperverbrossing bied.

A new and important aspect of the current year's work has been the investigation of the effect of carbide-forming elements ( i . e . vanadium, zirconium, niobium and titanium) on the hardenability of EN18 when different steel -making procedures »re employed. In particular the effect of steel k i l l ing by silicon and/or aluminium and titanium was investigated. Additions of vanadium which, if added together with aluminium and titanium, can give a Gross-mann hardenability factor of two using austen-it izing temperature: of 900 °C illustrates the results. Using this approach, it is thus possible to substitute the 0.3X Mo in EN19 with 0,11 V. Another example is the outstanding difference in hardenability that was achieved when vanadium was added together with sil icon, aluminium and titanium in the laboratory production of EN47 or 6150, as shown in Fig. 17.

"n Nuwe en belangrike aspek van werk die afge-lope jaar was die ondersoek na die effek van karbiedvormende elemente ' i . e . vanadium, sir-konium, niobium en titaan) op die verhardbaar-heidsvermoë van EN18 wanneer verskillende staalvervaardigingsprosedures toegepas word. In die besonder is die effek van staaltemming deur silikon en/of aluminium en titaan ondersoek. Die byvoeging van vanadium wat, as dit saam met aluminium en titaan bygevoeg word, 'n Grossmann-verhardingsfaktor van twee by 'n austenitiseringstemperatuur van 900 °C kan gee, il lustreer die resultate. Hierdie bena-dering maak d'* dus moontlik om die 0,3% Mo in EN19 met 0,1X v te vervang. 'n Verdere voor-beeld is die buitengewone verskil in verhard-baarheid wanneer vanadium saam met si l ikon, aluminium en titaan in die laboratoriumprodt*-sie van EN47 of 6150 bygevoeg word, soos in Fig. 17 aangetoon.

70

a. x i t

fO X \ i i •o u

* ° •• • a " a

ATV3

En47 or 6150

0 4 8 12 16 20 U 28 32 36 UO

Distance from quenched end / Afstand van gebluste kant (in 1,6mm)

FIGURE/FIGUUR 17 Hardenability curve for vanadium steel ki l led with si l icon, aluminium and titanium

Verhardbaarheidskromme vir vanadfum-staal wat met silikon, aluminium en titaan qetem is

In the case of zirconium additions to EN18, I t was found that the silicon ki l l ing had a

In die geval van sirkonlumbyvoeging tot EN18, is gevind dat die temmlng met silikon 'n

72

greater effect than the addition of aluminium. Figure 18 shows the result for an alloy containing 0,11% Ir (alloy SZ2) which provides hardenability equivalent to EN19. An important finding from the heat treatment point of view was that this effect was almost Independent of austenitizing temperature from 870 °C to 950 °C.

groter effek het as die byvoeging van aluminium. Figuur 18 toon die result ate vir 'n legering met 0,11* Zr (legerinq SZ2) met 'n verhardbaarheidsvermoe gelyk aan die van EN19. Uit die oogpunt van hittebehandeling is 'n belangrike bevinding dat die effek byna onafhanklik is van die austenitiserinqstempe-

X

I/I (/> c -o

I* 8 12 16 20 24 28 32 Distance frum quenched end / Afstand van gebluste kant (in 1,6mm)

F1GURE/FIGUUR 18

Hardenability curve for z i rconia steel k i l l e d with s i l i con

Verhardbaarheidsvermoëkromme v i r sirkoniumstaal wat met s i l i kon qetem is

T'.e current work has shown that carbide-forming elements, rarely used as hardenabil i ty enhancing elements because of the necessity of using high austenit izing temperatures to secure the i r so lub i l i t y in th t austenite, should be reassessed. By careful adaption of the steel-making processes and the correct k i l l i n g addit ions, excellent hardenabil i ty performance can be obtained.

Die huidiqe werk toon dat karbiedvormende e le-mente wat selde as elemente v i r verhoging van verhardbaarheid gebruik word vanweé' die hoe austenitiseringstentperatuur wat nodig is om oplosbaarheid in die austeniet te verseker, heroorweeg behoort te word, uitstekende ver-hardbaarheidsvermoéns kan deur vers igt iqe aan-passing van die staalvervaardigingsproses sn die reqte temmingbyvoegfngs verkry word.

Fe-Ah-A1 STAINLESS STEELS Fe-HH-Al VLEKVRY STAA1S00RTE

Iron-manganese-aluminium alloys show considerable potent ial as possible cheap alternat ives to conventional austenitic chroi. m-nickel stainless steels in many appl icat ions. The current investigation has taken two l ines of approach.

Yster-mangaan-aluminium legerings toon hoë potensiaal in t a l l e toepassings as moontlike goedkoop plaasvervangers v i r konvensionele auste r f t iese chroom-nikkel vlekvry staalsoor-t e . Die huidige ondersoek het 'n tweeledige benaderlnq.

73

First , a series of pure alloys has been produced in order to clari fy the phase diagram in the compositional ranges 28-34% Hh and 7-1IX Al . The limited amount of previous research has indicated that these compositional ranges are of special interest. Phase equilibria have been studied by means of X-ray di f f ract ion, optical and electron microscopy, and electron microprobe analysis, with particular emphasis on the determination of the austenite phase boundary. Obviously, accurate chemical analysis is a prerequisite for this type of investigation and work is in progress to obtain suitable data routinely. Once the phase equil ibr ia in the ternary system have been established, the investigation wil l be extended to include the effect of carbon additions. Early in this work, it was discovered that an ordered phase is present in many of these alloys (1982/83 Annual Report). This may prove to be an important source of strengthening of this type of alloy, and it is now being studied by X-ray diffraction and transmission electron microscopy in order to determine its precise structure (which may be 003 or L2[) and the details of the complex ordering reaction.

Secondly, the production of alloys which have been shown by previous research to have part i cularly promising properties has been undertaken. This has involved development of melting and casting techniques, and evaluation of analytical methods for compositional control. Procedures are now being developed to fabricate the alloys and to provide material for comprehensive mechanical testing, and corrosion and wear tests. Preliminary results indicate excellent tensile properties, as shown in Table 3. Values for two Cr-Ni austenitic stainless steels are shown for comparison.

MUTE CAST IRON

White cast irons are basically composed of chromium-rich carbides of the M7C3 form dispersed in a matrix of austenite antS/or one of its transformation products. These alloys ate characteristically used In abrasion-resistant applications. Current research is addressing two different approaches:

Eerstens is *n reeks suiwer legerinqs geprodu-seer om die fasediagram in die samestellings -gebiede 28-34X Kn en 7-11X Al duideliker t» maak. Die beperkte mate van vorige navorsing dui daarop dat hierdie samestellingsgebiede van besondere belang is . Fase-ewewig is be-studeer deur middel van X-straaldiffraksie, optiese- en elektronmikroskopie, en elektron-mikrosonde-analise, met besondere klem op die bepalinq van die austeniet-fasegrens. Akkurate chemiese analise is uiteraard 'n voorvereiste vir hierdie tipe ondersoek en werk om gereeld beskikbare data te verkry, is tans aan die gang. Sodra die fase-ewewig in die drieiedige sisteem vasgestel i s , sal die ondersoek uitge-brei word om die effek van die byvoeging van koolstof te ondersoek. Dit is vroeë'r in die ondersoek gevind dat 'n aeordende fase in baie van hierdie legerinqs teenwoordig is (1982/83 Jaarverslag). Dit mag 'n belangrike bron van versterkinc; in die tipe legering blyk te wees, en word tans met behulp van X-straal-diffrak-sie en transmissie-elektronmikroskopie bestu-deer om die presiese struktuur (wat DO3 of L2i mag wees) en die besonderhede van die komplek-se ordeningsreaksie te bepaal.

Tweedens is begin met die produksie van leqe-rinqs met belowende eienskappe wat deur vorige navorsing aan die l iq qebrinq is . Oit behels die ontwikkeling van smelt- en giettegnieke asook die evaluering van analitiese metodes om die samestellino te beheer. Prosedures om die leqerings te vervaardiq en om m<»teriaa1 vir meganiese, korrosie- en slytasie-toetse te produseer word tans ontwikkel. Voorlopige resultate toon uitstekende treksterktes, soos in Tabel 3 getoon. Waardes vir twee Cr-Ni austenitiese vlekvry staalsoorte word ter ver-qelyking aanqetoon.

WIT6IETYSTER

Witgietyster is basies saamqestel uit chroom-ryk karbiede van die tipe M7C3 wat in 'n matriks van austeniet en/of een van die trans-formasieprodukte daarvan versprei is. Hierdie legerings word gewoonlik in skuurbestande aan-wendinqs gebruik. Die huidiqe navorsing net twee verskillende benaderings:

74

TABLE/TABEL 3 Tensi*e properties of a Fe-Mn-Al-steel

Treksterkte-eienskappe van 'n Fe-Mn-Al staal

Yield stress Ultimate tensile strength

Elongation

Vloeispanning (MPa)

Breektreksterkte (MPa)

Verlenqing (*)

Fe-30Mn-10AMC-l,5Si Quenched from 1 000 °C Geblus vanaf 1 000 °C 560 920 65

Aged 1 h at 550 °C 1 uur verouder by 550 °C 900 960 40

Type/Tipe 316 290 570 50

Type/Tipe 304 280 760 60

• the use of a novel casting method to improve alloy touqhness

• modifications in alloy design to enhance abrasion resistance.

The suspension casting, or microchilling process, dates back to 1968 and has been employed mostly in the Eastern block countries, where it has prcducel microstructural refinement, improved mechanical properties and the control of shrinkaqe defects and segregation, especially in heavy section steel castings. The process consists of the addition of metallic powders into the mould cavity as a homogeneously distributed suspension in the melt. The purpose is to extract the superheat during solidification by forming numerous localized heat sinks which finally melt down becominq an integral part of the structure. The present application in the field of white cast irons is original.

A laboratory system has been constructed and shown to be effective in producing suspension-cast sections. The significant changes to the microstructure can be seen in Fig. 19, where the conventional material is compared with an equivalent suspension cast sample. In the former case, lonq aligned dendrites are evident whereas, usinq the new process, the structures are refined to give randomly oriented den-

• die gebruik van 'n nuwe gietmetode om die taaiheid van die legering te verbeter

• wysiginq tan die legerinqontwerp ten einde die skuurbestandheid te verhoog.

Die suspensiegieting, of mikroverkillingpro-ses, dateer uit die jaar 1968 en is meesal in die Oosblok-lande gebruik, waar dit mikro-strukturele verfyning, verbeterde meganiese eienskappe en die beheer van inkrimpingsdefek-te en segregasie, spesifiek in swaarprofiel van staalgietstukke teweeggebrinq het. Oie proses bestaan uit die byvoeqing van metaal-poeiers in die gietvormholte as 'n homogene-verspreide suspensie in die smelt. Die doel is om die superhitte tydens stolling te ont-trek deur die vorming van talle gelokaliseerde hittesinkputte wat uiteindelin smelt om 'n integrate deel van die struktuur te word. Die huidige toepassing in die veld van witgiet-yster is oorspronklik.

'n Laboratoriumstelsel is opqestel en blyk doeltreffend te wees vir die produksie van suspensie-gegote dele. Die betekenisvolle veranderings aan die mikrostruktuur kan in Fig. 19 gesien word, waar konvensionele mate-riaal met 'n ekwivalente suspensie-geqote monster vergelyk word. In eersqenoemde qeval kan lang gen'gte dendriete qesien word terwyl die struktuur met die nuwe proses meer verfynd is met dendriete in willekeuriqe orie'ntasies.

75

-;i-.<s> r . « : .

-' I" f-'-""feV < ^ - - M • & * .

• «** '" !:-•• : "•• 4 ~ " f c M

(b) FIGURE/FIGUUR 19

Micrographs showing the dendri t ic or ientat ions: (a) conventional cast ing, (b) suspension casting

Mikrograwe wat die dendrit iese orie'ntasies toon: (a) konvensionele q ie t i ng , (b) suspensiegietina

d r i t es . Both transverse and lonqituti inal specimens were sectioned and tested in compression with the results shown in Fig. 20. The suspension-cast al loy exhibi ts isotropic mechanical properties with simple shear fracture behaviour, in contrast to the conventional-cast a l loy.

The white cast iron al loy development ac t i v i t y has been reassessed and broadened as a result of closer contact with industry. In this process, i t has become important to produce re levant laboratory wear data which is transferable to industr ial appl icat ion. This, however, can only result from achievinq a proper understanding of the material fa i lu re mechanisms during the wear process. The data from such a study then forms a base for further microstructural design.

In order to study wear mechanisms in samples with di f ferent microstruc ures in terms of carbide size and d i s t r i b u t i o n , carbide type, volume f ract ion of carbides and matrix type, a series of seven experimental chromium-vanadium irons has been produced. Considerable care was taken in assessinq the effects of section thickness on microstructure to ensurp that mate r i a l s t ruc tura l ly consistent with 50 mm diameter mi l l bal ls was available for all tests. The alleys have been carefu l ly characterized usinq quanti tat ive metallography, and electron microprobe analysis has been used to determine the carbide compositions.

Beide transversale en lonqitudinale monsters is deurqesny en in kompressie qetoets met die resul tate soos aanaetoon in Fio. 20. Die sus-pensie-aegote leqerinq toon isotrop ;ese meqa-niese eienskappe met eenvoudige skuifbreuk-qedraq, in teenste l l inq met die konvensioneel-qeqote leqerino.

Die ak t iw i te i te in wi tq ietyster- leqer inqont-wikkelinn is heroorweeq en uitqebrei as qevolq van nouer kontak met die nywerheid. In h ier-die proses is dit belanqrik om relevante s ly -tasiedata in die laboratorium te produseer wat op nywerheidstoepassinqs van toepassinq qemaak kan word, f l i t kan eqter slegs qebeur indien die meqanismes wat tot fa l inq van die mate-r iaa l tydens die slytasieprosos lei deeglik begryp word. Die data van so 'n ondersoek vorm dan 'n basis v i r verdere mikrostrukturele ontwerp.

Ten einde die siytasiemeqanismes in monsters met verski l lende mikrostrukture te ondersoek met betrekkinq tot karbiedqroottes en -ver-spreidinq, karbiedt ipp, volumefraksie van kar-biede en die t ipe matriks, is 'n reeks van sewe eksperimentele chroom-vanadium ysters qe-produseer. Heelwat aandaq is qeqrp aan die bepalinq van die ef fekte van seksi°dikte op die mikrostruktuur, om te verseker dat mate-r iaa l wat struktureel konstant is met 50 mm deursnee meulballe v i r al die toptse beskik-baar was. Die lpqprinqs is snrqvuldiq deur kwantitatiewe metal loqraf ie aekarakteriseer en elektron mikrosonde-analise is qebruik om die karbiedsamestel1inqs te bepaal.

76

2 000

a.

c 'c c <t> Q .

l/>

\ «/) 01

00

(T)

Y,S.=12Q0MPa

Y.S.=7QQMPfl

0 4 8 12 14 20 24

Strain / Vervorming (%)

Conventionally cast material Konvensioneel gegote materiaal

(a) F1GURE/FIGUUR 20

0 4 8 12 14 20 24

Strain / Vervorming (%)

Suspension casts Suspensieqietinge

(b)

Compression tests results for the longitudinal (L) and transverse (T) sections of (a) conventional cast material and (b) suspension casts

Kompressie toetsresultate vir die longitudinale (L) en transversale (T) snitte wan (a) konvensionele gieting en (b) suspensiegietinq

The wear tests undertaken to date include hiqh stress abrasion tests on al l alloys in both as-cast and heat-treated conditions, and dry sand rubber wheel tests (low stress abrasion) are in progress. The performance of the new alloys appears promising with the material in the as-cast condition being comparable with the ful ly heat-treated chromium-molybdenum irons currently used in industry. Heat-treatment of the experimental alloys increased wear-life by an average factor of two. Detailed surface studies will now be used to characterize the material removal processes and relate this to microstructure. in parallel similar studies on some industrially worn components have been carried out and more are planned.

Die slytasietoetse wat tot op hede qedoen i s , sluit in hoe'spanninqskuurtoetse op alle lege-rings in beide die soos-geqote en hittebehan-delde toestande, terwyl droë-sand rubberwiel-toetse (laespanningafskuring) tans aan die gang is. Die werkverrigting van die nuwe lege-rinqs lyk belowend en die materiaal in die soos-gegote toestand is vergeblykbaar met chroom-molibdeen ysters wat ten voile hittebe-handel is soos tans in nywerheidsgebruik. Hittebehandeling van die eksperimentele lege-rings het die slytasieleeftyd met 'n gemiddel-de faktor van twee verleng. Uitqebreide opper-vlakondersoeke sal nou gedoen word om die proses van materiaalverwydering te karakteriseer en dit met die mikrostruktuur in verband te bring. Parallel hiermee is soortgelyke onder-soeke uitqevoer op onderdele wat industrieel qeslyt is , terwyl verdere ondersoeke beplan word.

77

The completion of this phase of the laboratory tests plus further pilot-plant ball a i l l tests • i l l provide a f i rn base for future development.

S U R F A C E T R E A T M E N T S A I D C O A T I N G S

The aim of this project, as the name indicates, is to undertake directed basic and applied research and development in the Metallurgical surface treatments f i e ld . This research may be broken down into three act iv i t ies:

• Processing studies • Surface layer characterization • Surface property evaluation.

These activities involve collaboration with other sections of the Metals Division, in particular the Surface Mechanical Properties Section.

Research Activities

A survey of South African industrial requirements in the surface treatments area was completed in September 1983. This survey was then 'ised, in conjunction with an earlier survey carried out in 1983 in Europe and the UK, as a basis from which to identify key areas for research and to set goals for the development of an appropriate infrastructure. As a result two broad areas for research have been identified in the Surface Treatments and Coatings Section. These areas are:

• Thermochemical treatments • Vapour deposition of metal lurgical

coatings.

Thermochemical treatments may be defined as heat treatments in which the chemical composit ion of an object or material is in ten t iona l ly changed by the di f fusion of one or more elements into/out of the surface. Examples of thermochemical treatments are carburizing (case hardening) and n i t r i d inq treatments appl ied to s leels. This area was chosen because of the Importance of such treatments to a

Die voltooiing van hierdie fase laboratorium-toetse asook verdere proefaanleg balaeultoetse bied 'n stewige basis vir verdere ontwikke-l inq.

O P P E R V L A K I E H A R D E L I I G S E N - B E D E K K I N C S

Die doel van hierdie projefc is OM, SOOS die naam aandui, geriqte basiese en toeqepaste navorsing en ontwikkeling in die Metallurgiese oppervlakbehandelingsveld te doen. Hierdie nt-vorsinq kan in drie aktiwiteite verdeel word:

• Prosesseringstudies • Karakteriserinq van oppervlaklae • Evaluering van oppervlakeienskappe.

Hierdie aktiwiteite vereis sawewerkinq Met ander seksies van die Afdeling Metale, in die besonder die Seksie Oppervlak Meganieê Eien-skappe.

Navorsings aktiwiteite

*n Opname oor die Suid-Afrikaanse nywerheids-vereistes in die oppervlakbehandelingsveld is in September 1983 vol tool. Hierdie opname is saam met 'n vroeere opname wat in 1983 in Europa en die VK gedoen is, as 'n basis ge-bruik om sleutelgebiede vir navorsing te iden-tifiseer en doelwitte te stel vir die ontwik-keling van 'n gepaste infrastruktuur. Twee breë navorsingsqebiede is qevolglik oeidenti-fiseer in die Seksie Oppervlakbehandelings en -bedekkinqs naamlik:

• Termochemiese behandelings ' Dampneerslaq van metallurgiese bedekkings.

Termochemiese behandelings kan gedefinieer word as hittebehandelings waarin die chemiese samestelUnq van 'n voorwerp of materiaal doelbewus verander word deur die diffusie van een of meer elemente van/na die oppervlak. Voorbeelde van termochemiese behandelings is opkolinq (dopverhardinq) en nitridering van staalsoorte. Daar is op hierdie navorslngsge-bied besluit weens die belanqrlkhefd van sulke

78

Modern engineering industry, and because pre

viously there has been no other accessible

research or development activity in this area

in South Africa.

In recent years there has been an increasing

awareness, particularly in the technologically

developed countries of the world, of the value

and immense potential of vapour deposition

methods for the production of technologically

useful materials. Of particular interest to

the Metallurgical industry has been the devel-

opaent of vapour deposited functional coatings

for Metallurgical engineering components.

Clearly vapour deposited coatings are an area

of significant interest to this Section.

Research Specifics and Future DevelopMents

THERHKHEMICN. TREATKHTS

Research has been undertaken on certain as

pects of the gaseous fer r i t ic nitrocarburizing

process. The process involves the diffusional

addition of principally nitrogen and carbon

into the surface of steel parts at tempera

tures usually in the range 570 - 580 °C . This

results in the formation of a surface layer

(typically 10 - 20 vm in thickness) on the

steel, which confers improvements in the wear

resistance of the steel surface, particularly

under sliding conditions. Industrially the

nitrocarburizing process has bed successfully

established, but on a rather empirical basis.

I t would seem that further improvement in this

type of process will depend on a better under

standing of the mechanisms operating during

the degradation of nitrocarburized surfaces in

service. One of the major stumbling blocks in

this respect has been the lack of a simple

method for the metallographic characterization

of the structure of the surface layer. Such j

characterization method has been developed

within this Section, which makes use of a

novel etchant and allows the resolution of

both surface layer microstructure and detail

of the substrate as well. The use of the

method is illustrated in Fig. 21. From a

practical point of view, the availability of

behandelings in 'n noderne ingenieursnywer-

heid, en omdat áaar voorheer) geen ander toe-

ganklike navorsing- of ontwikkelingsaktiwiteit

op hierdie gebied in Suid-Afrika was n>e.

'n Groter-wordende bewustheiri van die waarde

en groot potensiaal van danpneerslagmetodes

vir die produksie van tegnologies nuttige

•ater iale net die afgelope aantal ja re , veral

in die tegnologies-ontwikkelde lande van die

wêreld posgevat. Die ontwikkeling van funk-

sionele daMpneergeslaande bedekkings vir

metallurgiese ingenieurskomponente is van be-

sondere belang vir die metallurgiese nywer-

heid. Danpneergeslane bedekkings is duidelik

'n gebied van betekenisvolle belang vir hier

die Seksie.

Rararsinajbesonderhede en Toekomstige Ontwik-kelings

TERHOCHEHIESE BEHMOELIRES

Savorsing oor sekere aspekte van die f e r r i t i e -

se nitriedopkolingsproses is onierneem. Die

proses behels d*e diffusiei.. uevoeging van

hoofsaaklik stikstof en koolstof in die opper-

vlak van staaldele gewoonlik by temperature

van 570 - 580 °C . Oit lei tot die vorming van

'n oppervlaklaag (gewoonlik 10 tot 20 urn dik)

op die staal, wat verbeterings in die slyta-

siebestandheid van die staaloppervlak te-

weegbring, veral onder skuiftoestande. Die

nitriedopkolingsproses is industrieel goed ge-

vestig, hoewel op 'n redelik empiriese basis.

Oit wil voorkom dat sekere ontwikkeling van

hierdie tipe proses sal afhang van 'n beter

begrip van die meqanismes wat die verswakking

van nitriedopgekoolde oppervlakke tydens wer-

klng teweegbring. len van die qrootstruikel-

blokke in hierdie verband is die gebrek aan 'n

eenvoudiqe metode om die struktuur van die op

pervlaklaag metalloqrafies te karakteriseer.

So *n karakteriserlngsmetode wat 'n nuwe ets-

middel gebrulk en wat resolusie van beide die

mlkrostruktuur van die oppervlaklaaq en beson-

derhede van die substraat moontiik maan, is in

hierdie Seksie ontwikkel. Figuur 21 i l lustreer

die gebrulk van die metode. Vanuit 'n prak-

tlese oogpunt bled die evaluerlngsmetode van

die oppervlaklaagstruktuur nie sleqs 'n bruik-

th is method of evaluating surface layer struc

ture not ont/ offers a useful qual i ty control

t o o l , but should also lead ind i rec t ly to a

greater understanding of the performance of

nitrocarburized components in service.

bare gehaltebeheêrhulpmii-Jel n ie , maar behoort

Lïk indirek te l» i tot 'n bster begrip van die

werkverriqt inq van nitriedopgekoolde onder-

dele.

(a) Monophase surface layer Monofase oppervlaklaan

(b) Dual phase surface layer Dubbelfase oppervlaklaag

FIGURt/FIGUUR 21

Microstructure of ni trocarburized plain low-carbon steel

t ' ikrostruktuur van nitriedopqekoolde qewone laekoolstof staal

Following the development of the metallograph-

ic metnod discussed above, control led n i t r o -

carburizing treatments have been carried out

to produce a series of d i f ferent surface layer

structures on plain low-carbon steel mater ial .

The performance of the d . f e ren t surface lay

ers is beinq evaluated under s l id inq wear con

d i t i ons , in conjunction with the Surface Mech

anical Properties Sect on , f the Metals d i v i

sion. This work is c l ise to completion, and

i t is intended that the results of these

studies should be published.

Na die ontwikkelinq van die metallografiese

metode soos hier bespreek, is beheerde n i -

triedopkolinqsbehandelings uitqevoer om 'n

reeks verskil lende oppervlaklaaqstrukture op

yewone laekonlstofstaal te produseer. Die

werkverrigtinq van die verski l lende oppervlak-

lae onder skuifslytasietoestande word in same-

werking met die Seksie Oppervlak Meganiese

Eienskappe van die Afdelinq Metale evalueer.

Die werk nader voltoo ,nq en publikasie van

die resul tate van hierdie ondersoeke word be-

plan.

The most '.echnically advanced thermocheinical

treatments, and those which current ly offer

qreatest scope for future development, are the

plasma-assisted treatments which make use of

an abnormal direct current qlow discharqe to

assist mass transfer of the defus ing species.

These types of heat treatments ire current ly

being introduced into t i e South African heat

treatrnt/nt market. Suitable equipmen', for re

search into these types of processes is cur

rent ly on order, and is due for comrr issioninq

at NIMR towards the end of 1984. Associated

anc i l la ry equipment is beinq constructed in

the laboratory at present.

Die mees teqnie:-gevcrderde termochemiese be-

handelinqs, en ook die wat die grootste moont-

likhede v i r toekomstiqe ontwikkelinq bied, is

d i ' 1 plasma ge-assistperde behandel inqs, wat

van 'n abnormale qelykstroom-ql imontlading qe-

bruik i.iaak om massa-oordraq van die d i f fuse-

rende spesie te bevorder. Hierdie t ipe h i t t e -

behandelinqs word tans aan die Suid-Afrikaanse

mark bekendqestel. Geskikte toerustinq v i r

navors'ng oor hierdie t ipe prosesse, is tans

op beste l l ing en behoort tepn die eir.de van

1984 by die NiMN in wPikinq gestel te word.

Toepaslike bytomstiqp toerustinq word tans in

die laboratorium opqeriq.

80

http://eir.de

VAPOUR DEPOSITION OF KFTALLUR6ICAL COATINGS DAMPNEERSLAG VAN HETALLURGIESE BEDEKKINGS

Two classes of vapour deposition methods may

be ident i f ied wnich have outstanding potent ial

f o ' the deposition of metal lurgical coatings:

• chemical vapour deposition (CVD)

• reactive physicai vapour deposition (PVD).

Local interest has been shown in both these

technologies. Although the techniques behind

these types of deposition process »re advanc

ing rapid ly, considerable work remains to be

done to promote an understanding of micro-

structure - property relat ionships of coated

surfaces. Furthermore, substrate and in ter -

fac ia l effects play an important ro le in de

termining the properties of the coated surface

and w i l l , therefore, i nd i rec t l y influence

processing parameters. Consequently such

factors require invest igat ion.

Construction of equipment sui table for the

control led Jeposition (by CVD) of t i tanium

carbide, n i t r i de and carbonitr ide coatings is

current ly being completed. Iron-carbon and

iron-nitrogen al loy substrates are being pre

pared which w i l l be sui table for use in a

study of the role of substrate-derived carbon

ano nitrogen in the CVO of t i tanium carboni

t r ide coatings.

Meanwhile calculations have been, and w i l l

continue to be, performed using an established

model for CVD, to determine the theoret ical

optimum values nf the contr ' lab le variables

in the deposition process, ihe model is r e l a

t i v e l y simple, and assumes that the input

gases attain thermodynamic equil ibrium in the

reactc". The equi l ibr ium composition is found

by computer-aided direct minimization of the

to ta l Gibbs free energy of the system, using

an i tera t ive procedure, and requires knowledge

of thermodynamic data for every species that

miqht be present at equi l ibr ium.

Because of i ts s imp l i c i t y , the model has l im

i t a t i ons , both in general and in the par t icu

lar case of t i tanium carbide, n i t r i d e and car-

' joni t r ide deposit ion. I ts primary l im i ta t ion

l ies in the basic assumption of attainment of

Twee klasse dampneerslagmetodes met buitenge-

wone potensiaal v i r die neerslag van metal lur-

qiese bedekkings kan onderskei word:

• chemiese dampneerslag (CDN)

• reaktiewe fisiese dampneerslag (FDN).

Plaaslike belanqstelling word in albei hierdie

tegnieke getoon. Hoewel die tegnieke ten op-

sigte van hierdie tipe neerslagprosesse vinnig

verbeter, moet noq heelwat gedoen word om 'n

beter begrip van die mikrosiruktuur - eien-

skapverhouding van bedekte oppervlakke te be-

vorder. Verder speel substraat- en tussenvlak-

effekte 'n belangrike rol in die b'jpaling van

die eienskappe van die bedekte oppervlak en

sal dus indirek die prosesparameters beïn-

vloed. Hierdie faktore vereis dus ondersoek.

Die konstruksie van qesMkte toerusting vir

die beheerde neerslag (deur CDN) van titaan-

karbied, -nitried en -koolstofnitrie'* word

tans voltooi. Seskikte yster-koolstof en

yster-stikstof leqeringsubstrate word ook

voorberei vir 'n ondersoek na die rol van

koolstof en stikstof vanuit die substraat in

die CDN van titaankoolstofnitried bedekkinqs.

Intussen word berekenings, gebaseer op 'n er-

kende model vir CDN, voortdurend gedoen om die

teoretiese optimum waardes van die beheerbare

veranderlikes in die neerslagproses te bepaal.

Die model is relatief eenvoudig, en neem aan

dat die inkomende gasse termodinamiase ewewig

in die reaktor bereik. Die ewewigsamestelling

word met behulp van *n rekenaar bepaal deur

direkte minimiserinq van die totale Gibbs vry-energie van die sisteem deur 'n iteratiewe

prosedure. Dit vereis termor"'namiese data vir

elke spesie wat moontlik by ewewig teenwoordiq

kan wees.

Weens die onqekompliseerdheid daarvan net die

model alqemene beperkinqe en ook in die beson-

aer met betrekkinq tot titaanf.ai-bied, -nftried

en -koolnitriedneerslag. Die primêre beperking

1e in die aanname dat ewewiq bereik word. By

81

equilibrium. At higher flow rates or lower

temperatures, dwell time in the reactor may

not be long enough to ensure equilibrium in

the system. It may also be limited by the

availabil i ty and accuracy of thermodynamic

data. This applies particularly to the t i t a

nium compounds. Both titanium carbide and

titanium nitride exhibit a wide range of stol

en iometry and data for compositions away from

stoichiometric TiC and TiN are scarce. Fur

thermore titanium carbonitride is a solid

solution of titanium carbide and titanium

ni t r ide, and therefore besides non-stoichio-

metry one must allow for the effect of a non-

ideal solution. As yet calculations have only

been completed for stoichiometric TiC and TiN,

and ideal solution titanium carbonitride, but

refinements are in progress.

Another limitation ties in the assumption that

the coating does not interact in any way with

the substrate on which i t is deposited. In

the case of the titanium compounds on iron-

carbon and iron-nitrcgen substrates it seems

likely that a considerable degree of interac

tion will occur, both throuqh interdiffusion

of the iron and titanium, and more particular

ly through the outward diffusion of carbon or

nitrogen from the substrate into the layer.

On completion of construction, the laboratory

equipment will be us<»d to test the applicabi

l i t y of this model to investigate the effect

of the substrate-coatings interaction and from

this to develop an improved model for the

depositior proces',.

A few of the theoretical results obtained so

far 3re illustrated in the Fig. 22. These

r late to the deposition of stoichiometric

titanium carbide from titanium chloride, hy

drogen and methane g s mixture, and are in

terms of the process variables of temperature,

pressure, and titanium to carbon and hydrogen

to chlorine ratios in the gas mixture. The

variation in the position of the boundary be

tween sinqle- and dual-phase deposition re

gions is shown. This boundary line should not

in fact be affected by the assumption of stoi-

cniometry, since at the boundary the titanium

carbide will be of stoichiometric composition

anyway.

< ..82

hoé'r vloeitempo's of laer temperature is die

rustyd in die reaktor moontlik nie lark qenoeg

om ewewig in die sisteem te verseker nie. Oit

kan ook beperk word deur die beskikbaarheid en

akkuraatheid van die termodinamiese data. Oit

is veral van toepassing op die titaanverbin-

dings. Titaankarbied en titaannitried toon

albei 'n wye stoigiometriese reeks, en data

vir ander verbindinqs as stoigiometriese TiC

en TiN is skaars. Verder is titaankoolstof-

nitried 'n vaste oplossing van titaankarbied

en titaannitried. Daar moet dus toegelaat

word vir die effekte van 'n nie-ideile oplos

sing sowel as vir die nie-stoïgiometrie. Slegs

berekenings vir stoïgiometriese TiC, TiN en

titaankoolstofnitried in 'n ideale oplossing

is tans voltooi, maar verfynings is aan die

gang.

'n Verdere beperking lê in die aanname dat die

bedekking op geen wyse 'n interaksie het met

die substraat waarop dit neergeslaan is nie.

In die geval van titaanverbindings op yster-

koolstof en yster-stikstof substrate lyk dit

moontlik dat 'n aansienlike mate van interak

sie sal plaasvind, beide deur tussendiffusie

van die yster en tltaan en, meer spesifiek,

deur die uitwaartse diffusie van koolstof of

stikstof vanaf die substraat na die bedekking.

By voltooilng van die konstruksie sal die

laboratoriumtoerusting jebruik word om die

toepasba3"be1d van die huidige model te toets

om die effek van substraatbedekking-interak-

sies te ondersoek en om Meruit 'n verbeterde

model vir die neerslagproses te ontwikkel.

'n Aantal teoretiese resultate wat tot dusver

behaal i s , word in Fig. 22 gei'llustreer. Oit

verwys na die neerslag van stoïqiometriese t i

taankarbied uit 'n titaanchloried, waterstof

en metaangas menqsel, en wo~d aangedui in

terme van die prosesveranderlikes van tempera-

tuur, druk, titaan-tot-koolstof en waterstof-

tot-chloor verhoudings in die gasmengsel. Die

verandering in die posisie van die qrens tus-

sen enkelfase- en dubbelfaseneerslaggebiede is

aangedui. H1erd1e qrenslyn behoort nie deur

die aanname van sto'fgiometrie be'fnvloed te

word n1e, aangeslen die titaankarb'»d by die

grens in elk geval 'n sto'fgiometriese same-

stelling sal hê.

(a) The Effect Of Input H to CI Atomic Ratio On The Deposition Of TiC la) Die Effek Van Aanvanklike H tot CI Atomiese Verhoudinq Op Die Neerslaq Van TiC

1 -System pressure (atmospheres)

10-1

10-?

10-3

Both TiC and C deposited Beide TiC en C neerge-slaan

nly TiC deposited Slegs TiC neergeslaan

T2 - i — 06

— i — 0.7

- 1 — 0.8

Sisteemdruk (atmosfere) 10-i

10-2

10-3 0.3 o.i. os Input Atomic Ratio of Ti to total Ti+C / Aanvangs-Aroomverhouding Van Ti tot totale Ti+C

(b) The Effect Of Temperature On The Deposition Of TiC, [Hi / CCi] = 10 (b) Die Effek Van Temperatuur Op Die Neerslaq Van TiC, [ H] / [Cl] = 10

System pressure (atmospheres)

10-v

Sisteemdruk (atmosfere)

r io-i

Input Atomic Ratio of Ti to total Ti*C / Aanvangs-Atoomverhouding Van Ti tot totale Ti*C

FIGURE/FIGUUR 22

Calculations of the formation of TiC by chemical vapour deposition under different conditions

Berekenings van die vorming van TiC met chemiese-dampneerslag onder verskillende toestande

HEAT R E S I S T A N T A L L O Y S H I T T E BE S T A H 0 E L E 6 E R I N G S

The activities of the project have centred on the determination of the influence of casting parameters on the structure and resultinq mechanical properties of Ni-base superalloys. The aim of the work is to obtain structural control by means of controlling foundry variables. The programme supports two sponsored industrial contracts.

Sedrywighede in hferdie projek was gekonsen-treer op die bepaling van die invloed van gietveranderlikes op die struktuur en gepaard-gaande meganiese eienskappe van Ni-basis superlegerings. Die doel was om strukturele beheer deur mlddel van kontrole van die gieteryveranderlikes te verkry. Die program steun twee geborgde nywerheidskontrakte.

R3

Research Activities NworsingsAtiNÍteite

I t is well-known that successive casting runs

for the same heat of material can give unex

plained variat ions in propert ies. Normal

practice in commercial vacuum investment cast

ing u t i l i zes the introduction of the hot cer

amic mould through an airlock system. Experi

ments using th is technique showed the s e n s i t i

v i t y of measured room temperature mechanical

properties on, for example, mould temperature,

metal superheat, etc. For th is reason, i t be

came clear that process control was v i t a l to

be able to d ist inguish casting parameters and

use the information to correlate with proper

t i e s . To sat is fy these requirements, a res is

tance-heated mould furnace was f i t t e d to the

vacuum induction melting (VIM) f a c i l i t y allow-

i i g mould temperature control of ±5 °C, while

the addition of an opt ica l pyrometer provides

cont inue^ melt temperature data. F ina l ly in

order that each melt is f u l l y characterized, a

data acquisit ion and control system has been

interfaced allowing continuous recording of

melt and mould temperature, system pressure,

and monitoring of cooling rates at a number of

locations on the mould. This systeir is now

operative and i n i t i a l melts carried out.

A new investment casting mould configuration

has been designed to produce threaded speci

mens for high temperature tes t ing . By incor

porating a d i f ferent feed system a qreater

y ie ld of specimens per cast has been achieved

During the year a number of complementary

techniques have been established for the

microstructural evaluation of superalloys.

These include:

• optical metallography usinq various etch-

ants to enable iden t i f i ca t ion of the d i f

ferent phases in the al loy system

• quant i tat ive image analysis as a means of

measuring microporosity

Dit is bekend dat opeenvolgende giet lope v i r

dieselfde s te l materiaal onverklaarbare ver-

s k i l l e in eienskappe kan lewer. By kommersiêle

vakuum-presisiegieting word gewoonlik gebruik

gemaak van 'n warm keramiek-gietvorm wat deur

'n lugsluitsisteem ingebring word. Eksperi-

mente met hierdie tegniek toon die sens i t iw i -

t e i t van die gemete kamertemperatuur meganiese

eienskappe op, byvoorbeeld, gietvormtemppra-

tuur , metaalsuperhitte ens., aanqedui. Hier-

u i t het d i t duidel ik qeword dat prosesbeheer

noodsaaklik is om gietveranderl ikes te kan

onderskei en om die i n l i g t i n g te benut v i r die

korrelasie met eienskappe. Om aan hierdie

vereistes te voldoen is 'n weerstandverhitte

gietvormoond aan die vakuuminduksie smelt-

f a s i l i t e i t (VI3) geïnstal leer om gietvormtem-

peratuur akkuraat to t * 5 ° C te kan beheer.

Die toevoeging van 'n optiese pirometer lewer

deurlopende data oor giettemperature. Ten

s lo t te is 'n data-insameling en beheersisteem

v i r deurlopende opname van smelt en gietvorm-

temperatuur, sisteemdruk en die monitor van

verkoelingstempo's by 'n aantal punte op die

gietvorm gekoppel om elke smelt vo l leuig te

kan karakteriseer. Die sisteem is nou in wer-

king en die eerste aantal smelt? is afqehan-

de l .

'n Nuwe presisiegietingvorm-konfiqurasie is

ontwerp om monsters met skroefdraad v i r hoe-

temperatuurtoetsing te produseer. Deur 'n

ander voersisteem te inkorporeer, is 'n groter

opbrengs van monsters per giet verkry.

Gedurende die jaar is 'n aantal aanvullende

tegnieke v i r die mikrostrukturele evaluasie

van superlegerings gevestig. Dit s l u i t die

volgende in :

• optiese metal loqraf ie waarin 'n verskeiden-

heid etsmiddels gebruik word om versk i l len-

de fases in die legerirgsisteem te kan

ident i f iseer

• kwantitatiewe beeldanalSe as 'n metode om

mikroporeusheid te meet

• phase extract ion techniques combined with

X-ray d i f f r ac t i on for iden t i f i ca t ion of

minor phases

• transmission electron microscopy methods

for studying gamma prime prec ip i ta t ion .

M E C H A N I C A L B E H A V I O U R O F M E T A L S A N D A L L O Y S

The aim of th is project is to investigate

mechanical properties and correlate the per

formance with microstructure. At present the

ac t i v i t i es have concentrated on the establ ish

ment of expertise and f a c i l i t i e s to sa t is fy

the requirements of the other development pro

jects and specif ic investigations re la t ing to

contract work.

Research Activities

Durinq the year the Instron servo-hydraulic

instrumentation was upgraded and f i t t e d with

improved computer control and data acquisi t ion

capab i l i t i es . In addi t ion, a number of new

f i t t i n g s have been bu i l t or purchased to allow

the required tests of fracture toughness, high

temperature propert ies, etc. to be accommodat

ed. A creep/stress rupture machine is current

ly being commissioned and an instrumented im

pact tester is expected later in 1984, thus

increasing the range of measurements possible.

The study of the locally-developed corrosion-

resistant dual-phase steel (3CR12) has been

extended. The three-stage work-hardening be

haviour reported previously has been invest

igated in terms of active deformation mechan

isms in specif ic regions of the microstrur.ture

by using transmission electron microscopy to

study dislocation structures from specif ic

st ra in regions. Hicrostructural observations

have shown that deformation par t i t ion ing (as

indicated by detai led examination of tensi le

data) can be rat ional ized in terms of the re

l i e f of residual stresses in the martensite

phase.

As part of this continuing study, low cycle

fat igue behaviour of 3CR12 has been inves t i -

• fase-ekstrasie tegnieke gekombineer met X-

s t raa ld i f f raks ie v i r die iden t i f i kas ie van

k le iner fases

• transmissie-elektronmikroskopipse metodes

v i r die bestudering van gamma primêre pres-

s i p i t a a t .

N E G A N I E S E 6 E D R A 6 V A N N E T A L E EN L E G E R I N G S

Die doel van hierdie projek is om meganiese

eienskappe te ondersoek en die werkverr igt ing

met mikrostruktuur te korreleer. Tans is die

ak t iw i te i t e gekonsentreer op die vest iging van

kundigheid en die daarstel l ing van f a s i l i t e i t e

om aan dia vereistes van die ander ontwikke-

l ingsprojekte te voldoen en om spesif ieke kon-

t raktuele ondersoeke te dosn.


Die Instron servohidroulise apparaat is gedu-

rende die jaar verbeter en toegerus met verbe-

terde rekenaarbeheer en data-insamelingsver-

moëns. 'n Aantal nuwe onderdele is ook ver-

vaardig of aangekoop om die vereiste toetse

betreffende breuktaaiheid en hoë-temperatuur-

eienskappe ens. te kan ui tvoer. 'n Kruip- /

spanningsbreukapparaat word tans in diens ge-

stel en 'n geTnstrumenteerde slagtoetser word

la ter in 1984 verwag, wat die reeks moontlik-

hede v i r metinge verder sal u i t b r e i .

Die ondersoek na die plaasl ik ontwikkelde kor-

rosiebestande dubbelfasestaal (3CR12) is ver-

leng. Die dr ie-stadia werkverhardingsqedrag

waaroor voorheen vers lag gelewer i s , is onder

soek in terme van die aktiewe deformasiemega-

n<smes in spesifieke areas van die mikrostruk-

tuur deur van transmissie-elektronmikroskopie

gebruik te maak om die ontwrigt ingstrukture

van spesifieke vervormingsgebiede te onder

soek. Mikrostrukturele waarnemings toon dat

deformasieverdeling (soos aangedui deur 'n

uitqebreide ondersoek van die trekdata) gera-

sionaliseer kan word in terme van die v e r l i q -

t ing van residuele spannings in die marten-

s ie t - fase .

As deel van hierdie deurlnpende ondersoek is

lae-s ik lus vermoeidheidstoetse op 3CR12 onder

BS

gated under contract to Middelburg Steel and

Alloys (Pty) Ltd. The two types of steel, de

signated 3CR12 and SX3LR12 and differing in

nickel content, were again investigated under

tension-compression (R = -1) and tension-ten

sion (R = 0) conditions using total strain as

controlling parameter. By analysis of the

stress-strain hysteresis loops, the response

of the material was evaluated. The majority

of samples were cycled to fai lure in order to

obtain tota l -s t ra in- l i fe curves. Both types

of steel were cyclically loaded in the longi

tudinal and long transverse directions.

The 3CR12 steel, for both loading directions

under R = -1 conditions, exhibited cyclic

hardening, while in contrast the SX3CR12,

having a lvqer volume fraction of martensite

showed cyclical softening in general. When

cycled under tension-tension conditions both

steels revealed cyclic softening. The tota l -

strain l i f e curves obtained are shown in Fig.

23. The cehaviour has been found consistent

with work reported by others on different

dual-phase steels of lower alloy content.

A joint Israeli - South African research pro

ject is in proqress to investigate the effect

of strain rate and temperature on yielding and

fracture toughness phenomena in 3CR12 steels.

A suitable three-point bending fixture includ

ing a 'temperature tank' has been constructed

and is now being used to perform the necessary

fracture toughness experiments at low strain

rates. The high strain rate instrumented im

pact tests were performed with the fac i l i t ies

at ISCOR and the results are under evaluation.

D U C T I L E I R O N

Based on the desire of foundrymen to eliminate

microshrinkage in thick-section castings and

to improve the yield of metal in foundry

moulds, considerable interest has bet>n «hown

in the problem of volume chanqes occurinq

during solidification of cast iron as well as

ductile iron.

kontrak vir Middelburg Steel and Alloys (Pty)

Ltd. , gedoen. Die twee tipes staal , 3CR12 en

SX3CR12, wai. in nikkelinhoud verski l , is weer

ondersoek onder spanning-druk (R « -1) en

spanning-spanning (R = 0) toestande met tota-

le vervornsing as die behere.ide parameter. Die

materiaal se gedrag is deur analise van die

spanningvervorminq-histeresesiklusse evalueer.

Die meerderheid monsters is siklies vervorm

tot falinq ten einde totale-vervorming-lewens-

duurtekrommes te verkry. Albei staal-tipes is

in die longitudinale en lang transversale r ig -

tings siklies belaai.

Die 3CR12-staal toon sikliese verharding in

albei laairigtings vir toestande van R = - 1 ,

terwyl die SX3CR12 met 'n hoé'r volumefraksie

martensiet daarenteen oor die algemeen siklies

versagtinq toon. Tydens spanning-spanning

toestande toon albei stale sikliese versag

tinq. Die totale vervorming lewensduurtekrom-

mes wat verkry is , word in Fig. 23 aangetoon.

Daar is gevind dat die gedrag ooreenstem met

ander verslae oor werk op ander dubbelfase

staalsoorte met 'n laer legeringsinhoud.

'n Gesamentlike Israeli - Suid-Afrikaanse

navorsingsprojek is tans aan die qang om die

uitwerking van vervormingstempo en temperatuur

op swiqtinq en breuktaaiheidseienskappe van

3CR12-staalsoorte te ondersoek. 'n Geskikte

driepunt-buiqapparaat met 'n 'temperatuurtenk'

is opgestel en word tans gebruik om die ver-

eiste breuktaaiheidstoetse teen lae vervor-

mingstempo's uit te voer. Die hoë vervormings

tempo qeïnstrumenteerde slagtoetse is uitge-

voer met die fas i l i te i te by YSKOR en die

result ate word tans evalueer.

R E K B A R E Y S T E R

Weens die behoefte van qieterymanne om mikro-

inkrimping in gietstukke met dik gedeeltes uit

te skakel en die metaalopbrengs in qietvorms

te verhooq, word groot belanqstelling getoon

in die probleem van volumeveranderinqs wat

tydens stolling van gietyster en rekbare yster

plaasvind.

86

(/) o> c WJO

(Vol

> a» > -o =J 01 •^z.

0» a. • * — F o a) \ OJ

TD 3

• ^

. Q .

E n c <T} l_

^ oo . ÍU

— o

2 .0 -

Ó.8

0.6

0.1» - 3CR12I ^3CR12t

— SX3CR12I -o SX3CR12I

T 1 I T I I I 1—1—1~1—I I 102 1 0 3

Cycles to failure / Siklusse tot breuk (Nf)

• i i i

10*

FIGURE/FIGUUR 23

Plots of to ta l strain amplitudes vs. cycles to f a i l u r e for 3CR12 and SX3CR12

Ui ts t ipping van tota le vervormingsamplitudes vs. aantal siklusse to t breuk v i r 3CR12 en SX3CR12

Research Activities Naworsingsaktiwiteite

Experiments have been performed, using a purpose-built apparatus, on an unalloyed grey cas^ i ron, spheroidized and inoculated in the l i qu id stage prior to pouring into the mould as duct i le i ron. The carbon equivalent was varied from hypereutectic composition through eutectic (carbon equivalent (C.E.) ~4,3<) to hypo-eutectic.

The followinq conclusions have been drawn from the work to date:

• The maqnitude of volume shrinkage and subsequent expansion depends on carbon equivalent .

• I t was found that thp volume expansion continued in the sol id phase below the eutect i c transformation range, par t i cu la r l y in eutectic and hypo-eutectic compositions.

Eksperimente met 'n apparaat wat v i r die doel gebou i s , is uitgevoer op 'n ongeleqeerde grysgietyster wat in die vloeistof fase gesfe-roTdiseer en geinokuleer is voordat d i t as rekbare yster in die gietvorm gegiet i s . Die koolstofekwivalent is gevariee'r van die hiper-eutektiere na die eutektiese (koolstofekwivalent (K.E.)~4,3%) tot hipo-eutektiese same-s t e l l i n q .

Die volgende gevolgtrekkinqs is tot op hede u i t die ondersoek gemaak:

• Die grootte van volume-inkrimping en - u i t -set t inq daarna hang van die koolstofekwivalent af.

• Daar is gevind dat die volume-uitsett ing in die solleds fase onder die eutektiese transformasieveld, en vera! in die eutekt iese en hipo-eutektiese samestellinqs voortgesit i s .

R7

• The average rate of volume shrinkage is

higher than the rate of volume expansion.

S U R F A C E M E C H A N I C A L P R O P E R T I E S

The aim of the research programme is to qain a further and more comprehensive understanding of the effect of *.tructural and microstructur-al parameters on the deformation of surfaces, and near surface regions, during s l i d inq wear. The approach taken here is pr imar i ly based on the detailed examination of sub-surface deformation produced by control led s l id ing exper i ments. In addi t ion, the relat ionship between microstructure and abrasive wear properties in wh'te cast irons is under investigation in cooperation with industry.

Research Activities

DRY SLIDING HEAR

A block-on-rinq dry s l id inq wear r i g has been constructed and commissioned to monitor f r i c t i o n , penetrat ion, normal load f luctuat ions and wear rate during dry s l id ing wear exper i ments. Information obtained from the monitoring of these parameters is an important cont r ibu t ion to the interpretat ion of subsequent microstructural data.

Dry s l id ing wear experiments are underway at present to determine the relat ionship between wear behaviour, stacking fau l t energy (s . f .e ) and la t t i ce f r i c t i o n stresses in a ranqe of alloys that have been produced in the laborato ry . The aim is to relate dis locat ion ce l l structure^, evolved beneath the wear t rack, to parameters mentioned above. Table 4 i l l u strates the composition of the alloys under invest igat ion, which have been chosen to exh i b i t systematic variations in both stackinq fau l t energy and la t t i ce f r i c t i o n stress. The alloys have been f u l l y homogenized and characterized In terms of op t i ca l l y v is ib le micro-structure, grain size and hardness.

• Die gemiddelde tenspo van vo1us»-inkrimping

is hoe'r as die tempo van volume-ui tset t ing.

O P P E R V L A K N E G A N I E S E E I E N S K A P P E

Die doe I van hierdie navorsingsprogram is om beter en breé'r insig te verkry oor die uitwer-king van st rukture le en mikrostrukturele parameters op die vervorming van oppervlakke en suboppervlakst-eke tydens sku i fs ly tas ie . Die benadering sal in die eerste plek gthaseer word op 'n breedvoerige ondersoek van die sub-oppervlakvervorming wat met die beheerde skuifeksperimente verkry word. Die verwant-skap tussen mikrostruktuur en skuurslytasie-eienskappe van wi tg ie tys ter word ook in same-werking met die nywerheid ondersoek.

Navorsingsafctiwiteite

DROë GLYSLVTASIE

'n Blok-op-ring droë glyslytasiemeganisme is opqestel en in gebruik rieneem om wrywing, penetrasie, rorma1? Viai f luktuasies en s l y t a -sietempo tydens droé' glyslytasie-eksperimente te monitor. Bogenoemde i n l i g t i ng is van be-lang v i r die interpretasie van die mikrostrukturele data wat verkry word.

Die verband tussen slytasiegedrag, pakkings-fout-energie ( p . f . e . ) en roosterwrywingspan-ninq van 'n reeks legerings wat in die labora-torlum vervaardig i s , word tans deur droe glyslytasie-eksperimente bepaal. (lie oogmerk is om ontwrigt ingselstrukture wat onder die slytasie-spoorbaan ontwikkel het, in verband te bring met die bogemelde veranderl ikes. Tabel 4 i l l us t ree r die samestellinq van die leqerinqs wat ondersoek word en wat gekies is om sistematiese wysigings in pakkfngsfout-energie asook roosterwrywinqspanning aan te toon. Die legerings 1s ten voi le gehomogeni-seer en ten opsiqto van optiese sigbare mikrostruktuur, korre l -groot te en hardheid gekarak-ter iseer.

88

TABLE/TABEl 4

Prepared alloys for sliding wear research

Voorbereide legerings vir glyslytasie

Specimen Monster

s.f .e . , p.f.e {y'

Friction stress / « Wrywingspanning ' u '

Ni High - hoog Low - laag NÍ3Fe (disordered/ongeorden) High - hoog High - hoog Cu - 7X Al Lower - laer Low - laag Ni - 60* Co Low - laag High - hooq NijFe (ordered/georden) Super-dislocation - superontwrigting High - hoog

An essential part of the programme has been to establish the routine experimental conditions under which thin foils for transmission electron microscopy can be prepared from cross-sectional slices of wear tracks from a variety of alloys. The technique involves a combination of sputtering, electroplating, spark erosion and ion beam mill ing, and has been applied to the examination of sub-surface deformation.

'n Noodsaaklike deei van die program was om die roetine eksper intent el e toestande te vestig waaronder dun foelies uit deursnee skywe van slytasiespoorbane van 'n verskeidenheid lege-rings vir transmissie-elektronmikroskopie voorberei kan word. Die tegr 4°k kombineer verstuiwing, elektroplatering, vonkerosie en ioonbundelfreeswerk en word in die ondersoek van suboppervlakvervorming toegepas.

As part of the research programme a cooperative study has been undertaken, with the Surface Treatments and Coatings Section, to examine the effect of compound layers on deformation mechanisms during sliding wear of nitrocarburized surfaces. Dry slidinq wear tests have recently b.en concluded and transmission electron microscopy is currently being used to examine the deformation produced within surface layers.

As deei van die navorsingsprogram is 'n studie in samewerking met die Seksie Oppervlakbehan-delings en -bedekkings onderneem om die ui t -werking van saamqestelde lae op die vervor-mingsmeganismes gedurende glyslytasie van nitried-opgekoolde oppervlakke te ondersoek. Droë glyslytasie toetse is onlangs gedoen en die vervorming in die oppervlaklae word tans deur transmissie-elektronmikroskopie bestu-deer.

A study of the application of convergent t»am electron diffraction to dislocation cell structures has been initiated in cooperation with the Institute for Electron Microscopy of the MRC in Tygerberg. Convergent beam diffraction is a technique which is admirably suited to the study of cell miscrientations and is being used here to investigate the mechanisms by which cellular dislocation structures evolve during deformation. The preliminary study has revealed some interesting aspects of the effect associated with absorption of electrons by the specimen, and has

'n Ondersoek van die toepassing van konvergen-te bundelelektrondiffraksie op ontwrigting selstrukture is in samewerking met die Inst i -tuut vir Elektronmikroskopie van die MNR in Tygerberg onderneem. Konvergente bundeldif-fraksie is 'n hoogs gepaste tegniek vir die studie van selwanoriëntasies en word gebruik om ondersoek in te stel na die meganisme vir die ontwikkelinq van selontwriqtingstrukture tydens vervorming. Die voorlopige ondersoek het 'n aantal interessante aspekte getoon van die uitwerkinq wat met die absorbsie van elek-trone deur die monster geassosieer word. Dit

stimulated a more detailed study of electron-specimen interactions, presently beinq carried out in conjunction with the Materials Characterization Division.

ABRASIVE HEAR

A dry sand-rubber wheel abrasion tester has been commissioned and is being used, largely in cooperation with industrial concerns, to monitor abrasive wear behaviour in white cast irons. This particular fac i l i ty (unique in South Africa) has enabled work to be undertaken which conforms to internationally recognized specifications. The results are directly comparable with those quoted by laboratories overseas. Development work on weld overlay materials has constituted a major part of the work undertaken on abrasive wear, as has the study of white cast irons from the Alloy Development Project.

het gelei tot die huidige diepgaande ondersoek van die elektronmonster-interaksie wat in samewerking met die Af deling Materiaalkarakte-risering uitgevoer word.

SKUURSLYTASIE

'n Droësandrubberwiel-afskuurtoetser is in be-dryf gestei en word hoofsaaklik in samewerking met nywerheidsorganisasies gebruik om die af-skuurslytasiegedrag in witgietyster te bepaal. Met behulp van hierdie spesifieke f a s i l i t e i t (uniek in Suid-Afrika) kan werk aangepak word wat aan internasionaal erkende spesifikasies voldoen. Die resultate wat v mry is , is direk vergelykbaar is met die wat deur oorsese laboratoria gepubliseer word, 'n Groot deel van die werk wat op afskuur-slytasie onderneem is, was ontwikkelingswerk op sweisbedekkings-laagmateriaal asook 'n ondersoek na witgietyster vanuit die Legerinqsontwikkelingsprojek.

90.

SERVICES TO INDUSTRY AND OTHER ORGANIZATIONS

DIENSTE AAN D I E NYNERHEID EN ANDER OPGANISASIES

C E R A M I C S , G L A S S A N D P H A S E S T U D I E S

K E R A N I E K , G L A S E N F U S E -S T U D I E S

Numerous short-term services and longer-term

contracts were handled by the Division. The

following l ist gives an idea of the diversity

of work done:

Verskeie korttermyn dienste en 1 anger termyn

kontrakte is deur die Afdeling hanteer. Die

volgende lys verskaf 'n oorsig oor die ver-

skeidenheid werk wat onderneem is:

Glass production and analysis

Piezoelectric transducer development

Piezoelectric element production

Wear- and temperature-resistant ceramics

Ceramic powder evaluation

Single crystal growth

Heavy medium magnetic separation

Hot isostatic pressing studies

X-ray Laue studies on silicon

Room and high temperature X-ray diffraction analyses

Manufacturing processes for various chemicals

Dilatometric studies

Thermal conductivity measurement

Shear strengths of ceramics

Various literature searches

Infrared spectra determination

Thermal analysis of materials.

• Glasproduksie en -analise

• Piê'soê'lektriese omvormerontwikkeling

• Pié'soéTektriese elementproduksie

• Slytasie- en temperatuurbestande keramieke

• Keramiekpoeierevaluasie

• Enkelkristalgroei

• Swaarmedium magnetiese skeiding

• Warm isostatiese druk-ondersoeke

• X-straal Laue ondersoeke op si I ikon

• Kamer- en hoetemperatuur X-straaldif-fraksie-analises

• Vervaardigingsprosesse vir verskeie chemi-kaliê'

• Dilatometriese ondersoeke

• Termiese geleidfngsmeting

• Skuifsterkte van keramieke

• Verskeie literatuursoektogte

• Infrarooi-spektrabepaling

• Termiese analise van materiale.

E L E C T R O N I C M A T E R I A L S

The Division serves industry on a contractual

basis in the fields of vacuum technology, se

miconductor technology and device fabrication.

E L E K T R O N I E S E M A T E R I A L E

Die Afdeling dien die nywerheid op 'n kontrak-

basis op die gebied van vakuumtegnologle,

halfqeleierteqnologie en toestelvervaardiginq.

Services to industry and universities were provided in the following areas:

Dienste aan die nywerheid en universiteite is op die volgende gebiede gelewer:

• Vacuum tube devices

• Custom-made infrared devices

• Development of speci f ic semiconductor mater i a l s technologies

Assessment of materials requirements for specif ic devices

Infrared analyses of semiconductors

• Repair of specialized vacuum apparatus.

Vakuumbuis-toestel1e

In f ra roo i - toes te l le op beste l l ing gebou

Ontwikkeling van spesifieke ha l fge le ier -materiaal-tegnoloqieë.

Bepaling van materiaalvereistes v i r spesif ieke toeste1. le

• Infrarooi-anal ises van halfgeleiers

• Herstel van gespesialiseerde vakuumappa-ra te .

M A T E R I A L S Z A T I 0 N

C H A R A C T E R I - M A T E R I A A L K A R A K T E R I S E R I N 6

MASS SPECTROMETRY hASSASPEKTROMETRIE

The mass spectrograph is a powerful instrument for bulk analysis and has the capabi l i ty of simultaneous determination of a l l elements in a sample. In addi t ion, i t is one of the most sensit ive tools available to the analyst with detection capabi l i ty in the parts per b i l l i o n region. Table 5 gives a summary of the samples analysed during the past year.

Die massaspektrograaf is 'n kragtige i n s t r u ment v i r grootmaat-ontleding en is in staat om al die elemente in 'n monster gelyktydig te bepaal. Voorts is d i t een van die mees gevoe-l ige instrumente to t beskikking van die ana-l i s , met 'n bepalingsvermoe in die dele-per-bi l joen-gebied. 'n Opsomming van die monsters wat gedurende die afqelope jaar ontleed i s , word In Tabel 5 aanqegee.

TABLE/TARFL 5

Mass spectrografic analyses

Massaspektrografiesi» ontledings

L aboratory/Labor ator i urn Material/Materiaal Number of Samples/Aantal Monsters

Electronic Materials Elektroniese Materlale

Cd-Hg-Te, Si 6

Metals/Met ale T1, Cr, N1, Ni/Nb, Ni /Zr , A l , W 8

Ceramics, Glass and Phase Studies/ Keramiek, Glas en Fasestudies

A1 2 0 3 , Z r0 2 , S i 0 2 , S1C 11

Samancor S i 0 2 , S i , C 9

Research associated with Samancor analyses Navorsinq geassosieer met Samancor-ontledfngs

Geological standards/Geoloqiese stan-daarde Ooped matrices/Gedoteerde matrfkse Si/Aq/C/8/Be/P

4

25

92

ATOMIC SPECTROSCOPY, X-RAY FLUORESCENCE AND COMBUSTION TECHNIQUES

ATOOMSPEKTROSKOPIE, X-STRAALFLUORESSENSIE EN VERBRANDINGSTEGNIEKE

Samples for analy?is were received from other divisions of the NIMR. other CSIR institutes and industry. A variety of samples was handled, metals and experimental materials amongst others. Since the previous Annual Report the total number of samples has increased from 309 to 70S while the number of determinations has increased from 900 to 2674. The data are summarized in Table 6.

Monsters vir analises is van arder afdelinqs van die NIMH, ander UNNR-institute en nywer-hede ontvang. 'n Verskeidenheid monsters is hanteer, onder andere met ale en eksperimenttle materiale. Die totale aantal monsters het se-dert die voriqe Jaarverslag vemeerder van 309 tot 708 en die aantal bepalings van 900 na 2674. Die gegewens is in Tabel 6 opqesom.

TABLE/TABEL 6 Sumnary of analyses by means of four techniques

Opsomming van ontledings deur middel van vier tegnieke

NIMR/ NIMN

CSIR/ UNNR

Other/ Ander

Total/ Totaal

Atomic absorption/Atoomabsorpsie: No. of No. of

samples/Aantal monsters determinations/Aantal bepalings

80 224

7C 273

8 19

15P 516

Atomic emission/Atoomemissie : No. of No. of

sample:/Aantal monsters determinations/Aantal bepalings

32 120

6 18

28 36

66 174

Combustion/Verbranding : No. Of NO. Of

samples/Aantal monsters determinations/Aantal bepalings

361 1 0S4

- 6 24

367 1 078

XRF/XSF : No. Of No. of

samples/iantal monsters determine lons/Aantal bepalings

100 734

7 10?

10 67

117 906

TOT'.! /TOTAAL No. of No. of

samples/Aantal monsters deteriiir ations/Aantal b°palings

573 2 132

83 396

52 145

708 2 674

SCANNING ELECTRON MICROSCOPE/ENERGY DISPERSION X-RAY ANALYSER (SEM/EOX)

SKANDEERELEKTRONMIKROSKOOP/ENERGIEDISPERSIEUE-X-STRAALMIKROSONOE (SEM/EDX)

The SEM/EOX fac i l i ty continues to be well util ized as an integral part of many research projects within the CSIR, and as an aid in investigating industrial problems. Of the 154 investigations carried out during the year, 30* were for industrial companies, 40* for the NIMR and 30* for other CSIR institutes, universities and state-funded organizations. After twelve years of operation this instrument requires Increased maintenance time and expenditure to retain Its performance.

Die SEM/ECX-fasiliteit word steeds deeglik be-nut as 'n inteqrale deel van ta l le navorsings-projekte in die UNNR, asook as hulpmiddel by die ondersoek van nywerheidspribleme. Van die 154 wildersoeke wat gedurende die jaar ultge-voer is, was 30* vir nywerheidsmaatskappye, 40« vir die NIMN en 30* vir ander UNNR-institute, universiteite en staatsondersteunde organisasies. Na twaalf jaar diens vereis hlerdie Instrument toenemende onderhoudstyd en uitgawe om toerelkend te kan funksioneer.

ELECTRON MICR0PR08E ANALYSIS WITH UAVELENGTH DISPERSIVE X-RAY ANALYSIS

ELEKTRONMIKROSONDE-ANALISE MET GOLFLENGTE DISPERSIEWE-X-STRAALONTLEDING

Ouring the f i rs t year of operation following commissioning of this instrument, 36 investigations were carried out, Including seven for

Gedurende die eerste j *ar na hierdle instrument In werking gestel is , 1s 36 ondersoeke ultqevoer, waarvan sewe vir 1ndustr1ë'1e maat-

93

industrial companies. The following examples i l lustrate the capabilities of the aicroprobe analyser and its accessories:

Precise analysis of cadmium mercury t e l lurite

Detection of 0,1 mass X silicon in the aluminium metallization of an integrated circuit

Quantitative analysis of carbide precipitates in white cast irons and the measurement of the volume fraction of this phase using the on-line image analyser

Detection of a thin layer of silicon car

bide on a nickel substrate.

M E T A L S

During the past year the Metals Division has experienced a significant increase in its involvement with industry and other organizations. The number of major contracts, mainly concerned with alloy or process development, has more than doubled to five, and a number of further requests are under negotiation. In addition the Division provi«es a service for undertaking short-term problem solving studies and failure analyses and uses the expertise available to provide materials and process selection advice.

Twenty one Investigations ranging in length from one or two man-days to a month or more have been completed over the past year, and a further five ar€ In progress. There were approximately 90 - 100 requests for information regarding metal specifications, processing heat treatment, equivalent alloys and general metallurgical matters, most of which were handled telephonlcally. By establishing good contacts with other CSIR Institutes, many request* are received by referral. At present this work Is handled on an ad no* has1s throughout the Division and suitably experienced metallurgists ire being sought to establish a formal section to provide this essential service.

skappye «as. Die volgende voorbeelde illu-streer die venaoë van die nikrosonde-anali-seerder en bybehore:

• Noukeurige ontleding "an kadnium-kwik-tel-

luried

• Waarneming van 0,1 nassa X si 1 ikon in die aluminium-metallisering van 'n geTntegreer-de strooMbaan

• KKantitatiewe ontleding van karbiedpresi-pitate in witgietystersoorte en meting van die volumefraksie van hierdie fase met gebruik van die intydse beeldontleder

• Waarneming van 'n dun laag silikonkarbied op 'n nikkelsubstraat.

N E T A L E

Die afgelope jaar het die Afdeling Metale 'n merkbare toename in betrokkenheid met nywer-heids- en ander organisasies ervaar. Die aan-ta l g r . j t kontrakte wat hoofsaak1;k net lege-ring- of prosesontwikkeling verband hou, het meer as verdubbel na vyf, en onderhandelings oor verdere navrae is tans a?i die gang. Die Af deling bied verder 'n diens om kortermyn probleettioplossings en fal ingsondersoeke te doen, en gebruik beskikbare kundigheid om raad te gee oor materiaal- en proseskeuring.

Een-en-twintig ondersoeke wat van een of twee man-dae tot 'n maand of meer gewissel het, is gedurende die afgelope jaar afgehandel, terwyl 'n verdere vyf tans aan die gang is. Daar was ook ongeveer 90 - 100 navrae, die meeste te le-fonies, 1n verband met inligtlng oor n.etaal-speslfikasies, hittebehandelfngj, ekwivalente lenerinqs en alqemene Metallu'aiese sake. Deur goeie kontak met ander Institute van die WNNR te bewerksteillq Is ta l le navrae deur verwyslng ontvang. hierdie werk word tans deur die Afdeling op 'n ad hoc-basis hanteer, Gesklkte metallurge word gesoek om 'n formele seksie te vestig om hierdie noodsaaklike dlens te kan 1ewer.

94

The aliny development foundry acts as a core facility within the Division. The last year has seen a large demand on its services fro* other sections of the CSIR and from outside research organizations, particularly from industry and universities. In alloy produi-tion, 105 separate air-melts of 10 - 40 kg and IB vacuum melts of specifically requested compositions or process conditions have been made. In addition, some 30 requests ha v. been received for heat treatment work particularly from other institutes. Rolling of samples for other divisions of NIMR and universities has -iso been c?~r:ed out. This interaction shows an awareness of the Division's capability and is cost-effective in not duplicating faci l i ties unnecessarily.

The Division has certaii unique instrumento-tion and expertise. There has been particular interest in, for example, the ASTM standard dry sand/rubber wheel abrasion tester, and the considerable experience available in advanced optical and electron metalloqraphic techniques, vacuum melting of alloys, etc.

Die legeringontwikkelinqsgietery is 'n kern-fasiliteit in die Afdel'ng. Die afgelope jaar was daar egter n groot * aag na diens deur ander afd»lings van die WRNP en ander navor-sinqsorganisas.es, in die besonder van die nywerheid ar. universiteitc. Ten opsigte van legeringsproduksie is 105 afsonderlike lug-gietings van 10 - 40 kg en 18 vakuumgietings met spesifieke samestellings of prosestoestan-de gemaak. Ook is sowat 30 navrae vir hitte-behandelings ontvang, hoofsaaklik vanaf ander institute. Monsters is ook vir amter afde-lings van die NIMH en universitc*te gewals. Hierdie interaksie toon 'n bewustheid van die Af deling se vermoëns en is koste-doeltreffend aangesien geen onnodige duplisering van fasi-l iteite plaasvind nie.

Die Af deling beskik oor bepaalde unieke in-strumente en kundigheid. Daar is besondere belangstelling in byvoorbeeld die droë-sand/ rubberwiel skuur-toetser (volgens ASTM-stan-daarde) en die groot mate van ervaring wat in qevordere optiese- en elektronmetallografiese tegnieke, vakuumsmeltinq van legerings, ens. beskikbaar is.

http://sinqsorganisas.es

RESEARCH SUPPORT ACT 1 V I l I E S

NAVORSINGSTEUNBEORYMIGHEDE

A D M I N I S T R A T I O N A D H I I I W M S I E

GENERAL

The past year has been a challenging time for the administrative staff of the NIMR. On the one hand an infrastructure had to be established and expanded, and on the other, unique tasks relating to the establishment of a new institute had to be finalized. In this reqard, the following matters deserve? specific mention:

• A system was developed to enable more accurate reporting on the financial status of each project and contract, and to provide financial summaries for each division and the Institute as a whole.

• A complete filing system was developed for accurate recording of all incoming and outgoing correspondence, publications and reports.

• Capital equipment was taken over from NPRL and NMERI. This resulted in overall stocktaking of all equipment.

P Morsner Institute Secretary/Instituutsekretaris

ALGEHEEN

Die afgelope jaar was 'n tydperk van groot uitdaging vir die administratiewe personeel van die NIMN. Enersyds moes die nodige infra-struktuur daargestel en verder uitgebou word en andersyds moes eenmalige take wat noodwen-dig met die totstandkoming van 'n nuwe ins t i -tuut gepaard qaan, afqehandel word. In hier-die verband verdien die volgende sake spesi-fieke vermelding:

• 'n Stelsel is ontwikkel om meer akkuraat verslag te kan doen oor die finansiële stand van sake van elke projek en kontrak, en on finansiele opsomminqs van elke afdeling en die Instituut in sy geheel te kan verskaf.

• 'n Volledige liasseerstelsel is ontwikkel sodat akkuraat boek gehou kan word van alle inkomende en uitgaande korrespondensie, publikasies en verslae.

• Kapitaaltoerus.ing is vanaf NFNL en NNIMI ooroineem. Oit het 'n volledige opname v n alle toerustinq tot gevolg gehad.

96

«miMMERTS m RETIREMENTS MBTELIWS ER UITDIEISTREDIatS

• Cerastes, Class and Phase Studies

During the course of the year Drs I Sigalas and M M Thackeray were appointed heads of tfce Propeities of Materials and Electrochemistry Sections respectively.

Dr P Clayton, Mr H Stone, Miss R Brown, Miss M van Rensburg, Messrs A Louw, J Auret and B Berger were appointed, Mr G F Steyn resigned and Dr A Cohen's contract expired.

• Electronic Materials

Messrs A J Willis and M A Marais were appointed as research scientists in the general areas of surfaces, contact* and infrared studies of semiconductors.

• Materials Characterization

The following appointments were made: Messrs G Mpepo, W Barnard, D Theodorou, L Oosthuizen and Miss E Koch.

During the year Dr W H Gries, Mr E Rawsthorne and Mrs I Wardale resigned.

• Metals

On the 1st August 1983, the staff of the Metallurgy Division, NMERl were transferred to the Metals Division, NIMR. The members were:

Dr H Fidos (formerly Hear>- Metallurgy Division, NMERl, and now project leader for the Ductile Iron project)

Mr J N Kenworthy Mr D Luszcsewski Mr P J Makhoba Mr H J Otto Mr I M Sekhabi Mr Y SentarH Mrs H Snyders Mr J Speed (Industrial trdnlnq student).

• Keraaiek, 61 as ea Fasestwlfes

Gedurende die loop van die jaar is drr. I Sigalas en M N Thackeray aangestel as hoofde van die Seksies Eienskappe van Materiale en Elektrocheaie onderskeidelik.

Dr P Clayton, mnr N Stone, mejj. R Brown, M van Rensburg, anre A Louw, J Auret en B Berger is aangestel, mnr G F Steyn net be-dank en dr A Coren se kontrak het verstryk.

• Elektroniese HaU.-iale

Mnre A J Will is en M A Marais is aangestel as navorsingwetenskaplikL-s op die algemene ge-biede van oppervlakke, kontakte en infrarooi ondersoeke op halfgeleiers.

• Materiaalkarakterisering

Die volgende aansteilings is gemaak: Mnre G Mpepo, W Barnard, D Theodorou, I Oosthuizen en mej. E Koch.

Or W H Gries, mnr E Rawsthorne en mev. I Wardale het gedurende die jaar bedank.

• Met ale

Op 1 Augustus 1983 is die personeel van die Metallurgiese Afdeling, NNIMI oorgeplaas na die Afdeling Metale, N1MN. Die lede was.

Dr H Fidos (voormalige Hoof: Afdeling Metallurqie, NNIMI en tans projekleier vlr die projek Re (bare Yster)

Mnr J N Kenworthy Mnr D Luszcsewski Mnr P J Makhoba Mnr H J Otto Mnr 1 M Sekhabi Mnr Y Sentaril Mev. H Snyders Mnr J Speed (Student in bedryfsopleidlng).

During the year four «enters of staff resigned, applied for transfers to other institutes, or completed their contracts. They Mere:

Mr E C Barber Mr D Luszcsewski Mr P J Makhoba Or 0 0»on

New staff joining the Division since July 1983

are:

Miss N 0 Barnett Mr J M Benson Or AR Harding (Project Leader, Alloy

Development) Mr P D Hicks (on secondment a for f u l l -

time MSc deqree) Mr D Hope Or R D Jenkins Mr R Lowe Mr J Rabothatha Mr P Rossouw Or A Wells (Project Leader, Surface

Treatments and Coatings)

Four British industrial training university students spent periods of up to six months in the Division. They were:

Mr M W D Carr (Surrey University) Mr G Harding (Brunei University) Mr J Speed (Brunei University) Mr A P Stevens (Bath University)

The Division is assisted by two 'services rendered' staff:

Mrs S Biaqio Mrs A Lycett.

• Liaison and Information

The NIMR Liaison and Information Section was established towards the middle of April 1983 with the appointment of a Liaison Officer, Mrs Marleta Swart. During the past year Mrs Fran Obermeyer, workinq mornings only, was appointed to assist with visitors to the NIMR, l ibrary work and clerical tasks. Mrs May Dorlinq was transferred to this Section in February 1984. She has been appointed as Committee Clerk, and also assists with English editing/ translation and visitors, when required.

Gedurende die jaar net vier personeellede be-

dank, aar-.oek qedoen on 'n verplasing na ander

inst i tute, of hul kontrakte voltoo». Hulle is :

Mnr E C Barber Mnr 0 Luszcsewski Mnr P J Makhoba Dr D Oron

Nuwe personeellede wat sedert Julie 1983 by die Afdeling aangesluit het is:

Kej. NO Barnett Mnr J M Benson Dr A R Harding (Projekleier, Legeringont-

wikkeling) Mnr P 0 Hicks (Gesekonoeer vir 'n voltydse

MSc-graad) Mnr D Hope Dr R D Jenkins Mnr ft Lowe Nnr J Rabothatha Mnr P Rossouw jr A Wells (Projekleier, Oppervlakbehande

ling en -bedekking)

Vier Britse universiteitstudente in bedryfs-opleidina het tydperke van tot ses maande in die Afdeling deurgebring. Hulle was:

Mnr M W D Carr (Surrey Universiteit) Mnr 6 Harding (Brunei Universiteit) Mnr J Speed (Brunei Universiteit) Mnr A P Stevens (Bath Universiteit) .

Die Afdeling word byqestaan deur twee 'dienste gelewer' personeellede:

Mev. S Biaqio Mev. A Lycett.

• Skafcel- en Inligtingseksie

Die N1MN Skakel- en [nligtingseksie is teen die middel van April 1983 gevestig met die aanstellinq van 'n Skakelbeampte mev. Marieta Swart. Gedurende die afgelope jaar is mev. Fran Obermeyer aanqestei om behuipsaam te wees met besoekers dan die N1MN, biblioteekaanqe-leenthede en klerkl'.ke take. Mev. May Dorlfnq 1s In Februarie 1984 na die Seksie oorgeplaas. Sy is as Komiteeklerk aanqestel en is ook behuipsaam met Engelse redigsrlnc/vertalinq en besoekers, Indien nodlg.

• Ministration

The number of administrative staff «as increased by one additional post in the Word Processing Section, to cope with the expanded volume of typing.

L I A I S O N AND I N F O R M A T I O N

Two «.'•*• conferences were organized

• A Materials Symposium, 2 November 1983

• RSA - Republic of China Workshop on Semiconductor Materials, 7 to 11 May 1984.

Arrangements were made for numerous visi ts by scientists from abroad. Visitors who remained for a week or longer include Prof. Morris Cohen, MIT, a delegation from the Republic of China led by Prof. Choh H Li of the National Science Council, Taiwan, and Prof. H Rawson, formerly of Sheffield University.

About 350 South Africans from industry, universities, technikons and schools visited the NIMR durinq the past year, including the winners of the 19tk National Youth Science Olympiad, as well as the top science scholars in the Transvaal.

Many reports, publications and advertisements were euited/translated and a brochure on the activit ies of the Institute was prepared for publication as a TI-Technical Information for Industry, for publication in August 1984.

A computerized address l i s t , containing more than 500 names, was compiled to faci l i tate mailing of documentation generated by the NIMR.

Routine library matters were taken care of and a significant number of books and journals were cdered durinq 1983-1984 to provide for the information needs of researchers.

• AtfaiNlstraste

Een bykomende pos is in die Uoordverwerking-seksie geskep om die groter volume tikwerk te hanteer.

S K A K E L I N G EN I N L I G T I N G

Twee belanqrike konferensies is qereel

• 'n Materiaalsimposium, 2 November 1983

• RSA - Republiek van China Werksessie oor Halfgeleiermateriale, 7 tot 11 Nei 1984.

Reelings is getref vir besoeke deur 'n hele aantal oorsese wetenskapl ikes. Besoekers wat v ir 'n week of lanqer gebly het, s lui t in prof. Morris Cohen, MIT, 'n afvaardiging van die Republiek van China onder leiding van prof. Choh H Li van die Nasionale Wetenskap-raad, Taiwan, en prof. H Rawson, voorheen van Sheffield Universiteit.

Ongeveer 350 Suid-Afrikaners uit die nywer-heid, universiteite, technikons en skole het die NIMN die afgelope jaar besoek, insluitende die wenners van die 19de Nasionale Jeug Weten-skap Olimpiade, asook die beste wetenskapstu-dente in die Transvaal.

Talle verslae, publikasies en advertensies is gerediqeer/vertaal en 'n brosjure oor die be-drywiqhede in die Instituut is voorberei vir publikasie as 'n TI-Teqniese Inligting vir die nywerhe'd vir publikasie in Augustus 1984.

•n Gerekenariseerde adreslys, bevattende meer as 500 name is opgeste' om die versendinq v*n dokumentasie wat deur die NIMN voortqebring word, te vergemaklik.

Roetine biblioteekaangeleenthede het aandaq geniet en 'n aansienlike aa.ital boeke en tyd-skrifte is gedurende 1983-19B4 bestel om in die inligtinqsbehoeftes van n;vorsers te voor-sien.

99

PUBLICATIONS, REPORTS AND LECTURES

PUBLIKASIES, VERSLAE EN LESINGS

R E S E A R C H P U B L I C A T I O N S 1 A V O R S I N G P U B L I K A S I E S

* Member of another i ns t i t u te or organization * Lid van 'n ander ins t i tuu t of organisasie * * Work done before appointment as NIMR sta f f * * Werk gedoen voor aanstel l ing as NIMH-

menber personeell id * * * V is i t i ng sc ient is t * * * Besoekende wetenskaplike

1 . J H BASSON & H BOOYENS The introduction of m is f i t dislocat ions in HgCdTe expi taxia l layers

Phys. Stat . Sol. (a) 80 (1983) 633

2. H BOOYENS, J H BASSON, A W R LEITCH*. M E LEE* t C N STANOER 6aAs surface oxidat ion-related photoluminescence transients

Surf. S c i . , 130 (1983) 259

3. H BOOYENS**, G R PROTO* I J H BASSON** Strain effects associated with SiO layers evaporated onto GaAs

J . appl. Phys., 51 (1983) 1251

4. A P BOTHA**. S KR1TZ1NGER* <. R PRETORIUS* Solid state interact ion between th in chromium f i lms and s i l i con - a comparison between

amorphous and single crysta l s i l i con Thin Sol id Films, 105 (1983) 237

5. C CLAASE, A STRASHEIM*. M E THAIN* M M HALTERS* Developments of a versat i le emission spectrometer

Pulse, (March/Maart 1984) 30

6. U I r DAVID*, J B GOODENOUGH*. M M THACKERAY & M G S R THOMAS* The crysta l structure of LÍ2Mn02 Rev. Chim. miner., 20 (1983) 636

7. W I F DAVID*, M M THACKERAY, P G BRUCE* & J B GOODENOUGH* Lithium insert ion into B-Mn02 and the ru t i l e -sp ine l transformation

Mater. Res. B u l l . , 19 (1984) 99

8. CM DEMANET** XPS study ?f an indus t r ia l l y sulphided commercial COMO/YA1 20 3 catalyst

S.A. J . Chem. 37 (1984) 48

9. CM DEMANET** * J G H DU PREEZ* The chemistry of uranium - Part 32. The electronic structure of UCli, and ThCli,

complexes of some neutral donor llgands Inorg. Chem. Acta Le t te r , 77 (1983) L167

10. CM DEMANET** Estimation of the charging effect observed in the XPS study of thin films of Inorganic compounds

Inorg. Chem. Acta Letter, 76 (1983) L273

11. C M DEMANET** ft M STEINBERG* Influence of the temperature on an industrial C0/M0/AI2O3 catalyst: an XPS study

Appl. Surf. Sci., 14 (1983) 271

12. N P FERREIRA, J A STRAUSS & H G C HUMAN Developments 1n glow discharge emission spectrometry

Spectrochlm. Acta, 388 (1983) 899

13. D GERLICH* & S HART Pressure dependence of the elastic moduli of three austenitic stainless steels

J. appl. Phys., 55 (1984) 880

100

D GERLICH* ( S HART The second order pressure derivatives of the elastic moduli of a machinable glass ceramic

J. appl. Phys., 55 (1984) 877 D GERLICH*, S HART I 0 UHITTAL

Pressure derivatives of the elastic moduli of the rut i le structure di-fluorides Phys. Rev. - B Solid State, 29 (1984) 2142

0 GOLDMAN Mechanism and kinetics of reactions in the system Ni-Ti-0

J. Am. Ceram. Soc, 66 (1983) 811

P D HICKS** t F P A ROBINSON* I,as ion implantation a commercial future?

The Metallurgist and Materials Technologist, 16 (1984) 284

A I KINGON, L J LUTZ*, P LIAW* * R F DAVIS* Thermodynamic calculations for the chemical vapour deposition of silicon carbide

J. Am. Ceram. Soc, 66 (1983) 558

A I KINGON, L J LUTZ* I R F DAVIS* Thermodynamic calculations for the chemical vapour deposition of silicon nitride

J. Am. Ceram. S o c , 66 (1983) 551

A I KINGON, B V HIREMATH* I J Y BIGGERS* Reaction seguence in the formation of lead zirconate lead titanate solid solutions:

Role of raw materials J. Am. Ceram. Soc, 66 (1983) 790

U KLEMENT*, P U RICHTER & J B CLARK Meiting and solid-solid transitions at HP for PbCl 2, PbBr2, CdCl 2, CdBr2, Cd l 2 , SrBr2 and BaCl 2 ,

High Temp., High Press., 15 (1983) 539

S D 01 SEN ( R G B6HMER* The inductively coupled plasma as spectroscopic source

Analytika-Supplement to Chemsa, 10 (Jun 1984) 5

S D OLSEN & A STRASHEIM* Correlation of the analytical signal to the characterised nebulizer spray

Spectrochim. Acta, 38B (1983) 975

C J RADEMEYER*, H G C HUMAN ft P K FAURE* The electrical resist ivity of some graphitp types as used in electrothermal

atomic absorption spectrometry Spectrochim. Acta, 38B (1983) 945

D E C ROGERS J P F S JACKSON* Analysis of high alloy metals using a mass spectrograph f i t ted with a low

voltage discharge source Int . J . Mass Spect. & Ion Phys., 47 (1983) 283

I SIGALAS, J 8 CLARK & S HART Shear strength measurements at high temperatures and pressures

High Temp., High Press., 15 (ig83) 553

C M STANDER t K -J RANGE* Determination of valence-electron conceniration in AgTe3 by electron energy loss spectroscopy

Solid St. Comn., 47 (1983) 843

C M STANOER Energy loss spectroscopy of oxygen chemisorption on t in

Appl. Surf. Sc i . , 16 (1983) 463

A STRASHEIM*, M E THAIN*. N M WALTERS*, C CLAASE, H 5 C hViAN Í- N P FERREIRA New versatile computer-controlled direct readinq emission spectrometer

Spectrochim. Acta, 38B (1983) 921

H J STRYDOM & W H GRIES A comparison of three versions of Sigmund's model of sputtering using experimental results

Radiat. Eff. Letters, 86 (1984) 145

I LE R STRYDOM 4 G N VAN WYK* Measurement of carbon and silicon bulk-to-surface segregation in a polycrystalline Ni-Cr alloy

by means of Auger electron spectroscopy S. Afr. J . Pbys., 6 (1983) 56

32. I IE R STRVDOM I G N VAN UYK* The composition and bonding character ist ics of the al loying eleiaents in electrodeposited Ni-Cr al loys

Electrochim. Ac t ) , 28 (1983) 1817

S3. M M THACKERAY, U I F DAVID*, P 6 BRUCE* t J 6 G00OEK0OSH» Lithium insert ion into manganese spinels

"a te r . Res. B u l l . , 18 (1983) 461

34. M M THACKEitAY, W ! F DAVID*, P G BRUCE* fc J B G00DEN0UGH* Structural character ist ics of L i ^ e i O , , , L i x Pn 3 O w and L i -Fe 2 0 3 (0<x<2)

Studies in Inorganic Chemistry, 3 (1983) 801

35. M M THACKERAY, P J JOHNSON, L A DE PICCIOTTO , P G HH'C":* fc 0 B GOODcNOUGH* E lec t rochemica l e x t r a c t i o n o f l i t h i u m from LiMn 2 0i ,

Mater . Res. B u l l . , 19 (1984) 179

36. AH VICTOR* & D E C ROGERS Determination of u l t ra - t race amounts of thorium in NIM-0 and NIM-P standard geological

reference materials using ra t ion exchange chromatography and spark source nass spectrography Geostandards Newsletter, 7 (1983) 331

G E N E R A L A R T I C L E S A c G E M E N E A R T 1 K E L S

1. J B CLARK Materials for today and tomorrow

Power & Plant in Southern Afr ica (Aug 1983) 4

2. J B CLARK Materials research and the ro le of the National I ns t i t u te for Materials Research in South Af r ica

South African Journal of Science, 80 (Apr 1984) 150

3 . C M DEMANET Cancer and chemistry Clinica (Jan 1984) 6

4 . S HART A matter of mater ials: Glass

Archimedes, 25(3) (Jul 1983) 17

5. A WELLS Vapour deposition of metal lurgical coatings - An introduct ion to the technology

FWP Journal, 24 (1984) 63

R I M R R E P O R T S N I H N - VE R S L AE

Contract reports are not avai lable fo r Kontrakverslae is nie v i r verspreiding d i s t r i bu t i on . D is t r ibut ion of other beskikbaar n ie . Verspreiding van ander reports is subject to approval by the verslae is onderhewig aan die goedkeuring Chief Director van die Hoofdirekteur

1 . C J BADENHORST, P W RICHTER & S HART CMAT 15 Sodium n i t r i t e

Sep 1983

2 . C J BADENHORST, P W RICHTER 8. •> HART LMAT 16 Zinc ox ide

Jan 1984

3 . J H BASSON, H BOOYENS & R J MULLER CMAT 4 Sponsored repo r t on mercury cadmium t e l l u r i d e

Feb 1984

4. J H BASSON, H BOOYENS, A P BOTHA, C J BOTHA, C B MILLS, CMAT 61 L R WILTON I R J MULLER

Sponsored report on mercury cadmium telluride materials technology Aug 1983

102

5. J H BASSON, R o MULLER, C J BOTHA, H 800VENS, C B MILLS, N D STANDEN, CMAT 4 R LOMBAARD A R VAN UYK

Sponsored report on mercury cadmium telluride materials technology Mar 1984

6. J BATTY, J BEDNARIK & S HART CMAT 62 Feasibility study o.i the production of materials for infrared optical applications

Feb 1984

7. J BEDNARIK CMAT 56 Sponsored report on the production situation at Glamosa (Pty) Ltd Factory, Estcourt

Oct/Okt 1983

8. F BLUM CMAT 57 Low cycle fatique studies of 3CR12 steels

Jan 1984

9. H BOOYENS, J H BASSON I C B MILLS CMAT 18 Sponsored report on group I I I -V semiconductor materials technology

Oct/Okt 1983

10. H BOOYENS, R H ANDREWS, W DRIJFHOUT ft W N H VAN DEN BERG CMAT 3 Sponsored report on tube development

Jul 1983

11. A P BOTHA, C B MILLS, H BOOYENS, M A MARAIS, A J WILLIS, CMAT 79 C M STAJDE3, C M DTMANET, V WATTERS, A W R LEITCH ft J S VERMAAK

Sponsored report on qroup UI -V semiconductor materials technology Apr 1984

12. M W D CARR & N R W I N S CMAT 18 Metallurgical investigation of three gray Cost iron cylinder liners

Nov 1983

13. M W D CARR & Y MILO CMAT 80 Investigation of fai led car stabilizer "jars

Mar 1984

14. C CLAASE, A LOUW, C B MILLS, I LE R STRYDOM ft M E THOMAS SMAT 17 Verslag oor die werkstudiegroep vir elektroniese dienste in die NIMR

Jun 1984

15. J B CLARK IMAT 33 Overseas Report, Aug 1983

Oct/Okt 1983

16. J B CLARK IMAT 30 Report on visit to the USA, Mar - Apr 1984

May/Mei 1984

17. J B CLARK, Editor IMAT 43 Report on visit by SA Materials Science and Enqineerinq Oeleqation to

Republic of China Sep 1983

18. A COHEN, P SMIT, B BERGER & A I KINGON CMAT 99 Investigations into the 'Processing of Alumina Ceramics'

Foundation for Research Development Jun 1984

19. N R COMINS ft H SNYDERS CMAT 68 Meta'lurgical investigation of ground engaging parts

Feb 19E4

20. N R COMINS ft B Z WEISS CMAT 52 Investigation of failed pinion base bolts

Mar 1984

21. N R COMINS CMAT 67 Examination of CuBe mould material

Feb 1984

22. N R COMINS CMAT ' 0 Report on visit to NIMR by Profs C-T Hu, T-B Wu and Mr C-R Lin

Aug 1983

103

0 H OALTON Sponsored «-eport on foundry variables

Feb 1984

o H OALTON Report on sponsored res'-arch

Feb 1984

CHAT 69

CMAT 70

J H OALTON Report on sponsored research

Mar 1984

CHAT 75

G C DU PLESSIS, P W RICHTER & S HART CHAT 77 Report on sponsored research

Apr 1984

R FENN* & G A HARDING CMAT 88 Investigation of a fai led brazed joint

Hay/Mei 1984

J T FOUR IE ( M R COMINS SMAT 15 A working group report on an analytical electron microscope

Jun 1984

L J V GRANT The computer-controlled microphotometer. Compiled for MINTEK

Mar 1983

CHAT 107

L D V GRANT CMAT 108 The computer-controlled microphotometer. Compiled for UCOR

Aug 1983

W H GRIES & H J STRYDOM SMAT 3 A table of normalized sputtering yields for mono-elemental polycrystalline

targets Jan 1984

W H GRIES & I L VAN MAARSEVEEN A table of ion-implanted fiuences in mono-elemental polycryst ..lline solids

for 99% ind 95* retention Jan 1984

SKAT 4

W H G3IES Fist digitizing of analogue-recorded mass spectra by means of

an X-Y digi t iz - • board Jan 19C4

IMAT 23

S HART Report on overseas visi t

Jul 1983

IMAT 9

S HART Report of the working group on refractories

Jun 1984

SMAT 8

S HART Report of the working group on crystal growing

Jin 1984 SMAT 9

H G C HUMAN & N OMENETTO* The use of the thermal lens effect for enhancement of sensitivity in

molecular absorption spectrometry, with special reference to the use of a pulsed dye laser as source

Mar 1984

IMAT 7 EUR 9193 EN

H G C HUMAN Verslaq oor oorsese besoek. September 198? - Augustus 1983

Nov 1983 IMAT 24

D S JONES, D E C ROGERS & C CLAASE INTERACT a 'user-frif:nd1y' program for high precision mlcrophotometric

evaluation of Ion plates from the Varian MAT mass spectrograph Jun 1984

IMAT 3

40. R KAUERAUF & A I KIN30N CMAT 3S Report on sponsored research

Nov 1983

41. J N KENW0R1HY «.MP SHAW CMAT 64 Report on sand/rubber wheel testing of weld-overlayed plates

Mar 1984

42. J N KENUORTHY & M P SHAW CMAT 65 Investigation cf weld-overlay materials

Mar 1984

43. A I KINGON I P J TERBLANCHé CMAT 98 Sponsored report on quality control of electrical ceramics

Jun 1984

44. A I KINGON, R J STEAD & S HART CMAT 60 Report on the preparation of calcium oxide stablized zirconia

Feb 1984

45. A I KINGON & P J TERBLANCHé CMAT 86 Sources of variabil i ty and non-reprjducibility in the production of PZT-4

and PZT-8 ceramics May/Mei 1984

46. A N KIRKBRIDE CMAT 92 Metallurgical investigation into a failed sector-shaped ti lt ing-pad bearing

May/Mei 1984 47. A N KIRKBRIDE & G HARDING CMAT 96

Metallurgical investigation into the failure of a transportable gas cylinder May/Mei 1984

48. A LOUW, G BERKOW & N P YOUNG CMAT 90 Report on sponsored research

Muy/Mei 1984 49. A LOUW CMAT 91

Report on sponsored research May/Mei 1984

50. A MAJEWSKI, Y TRINQUET & A I KINGON CMAT 11 Advanced transducer materials: Progress in piezoelectric ceramic/polymer composites

Oct/Okt 1983 51. J I MCQUEER CMAT 63

Investigation of fractured valve spring Mar 1984

52. J I MCQUEER IMAT 5 Abrasion resistant white cast irons

Aug 1983 53. J I MCOUEER & Y SENTARLI CMAT 50

White cast iron development Jan 1984

54. A A MEINTJES, K I KROOK, J R MARTENS, A VAN ZYL & C RADEMAN CMAT 6 Preparation of lead sulphide (II)

Aug 1983 55. A A MEINTJES, K I KROOK, J R MARTENS, A VAN ZYL & C RADEMAN CAMT 6

Preparation of l*>ad sulphide (III) Feb 1984

56. A A MEINTJES, K I KROOK, J R MARTENS, A VAN ZYL & C RADEMAN CMAT 94 Characterization of lead sulphide (IV)

May/Mel 1984 57. Y MILO t> A R HARDING CMAT 66

Sponsored report on rock-driil steels Feb 1984

58. Y MILO, N R COMINS 4 0 ORON CMAT >7 Final Report. Mo-free alloys

Jun 1984

105

D P MOUTON, A J NEPGtN & A I KINGON Report on sponsored research

Jul 1983

CHAT 27

A J NEPGEN Report on sponsored research

Oct/Okt 1983

CMAÏ 10

A J HEPGEN, R KAUERAUF, D NIEUWC'IOT * R P STEPHENS Report on sponsored research

May/Mei 1984

A J NEPGEK Report on sponsored research

Oct/Okt 1983

CHAT 89

CHAT 9

S D OLSEN Report on visit to Europe, June-July 1983

Oci/Okt 1983

IMAT 31

H RAWSON Glass research at NIMR. Present and possible future interactions

with South African Industry Jun 1984

SMAT 7

P U RICHTER, J ODENDAAL & S HART Ceramics for specialty applications

Sep 1983

P W RICHTER Report on visit to England, Germany and I ta ly

Jul 1983

CMAT 47

!MAT 19

D E C ROGERS, D S JONES, J W WEGMAN, L 3RAIN & A C VAN UAMELEN A mass spectrographic investigation of the methods for obtaining quantitative analyses for the mass balance of P and B through a

submerged arc silicon smelter Nov 1983

IMAT 10

Y SENTARLI The preparation of 'The Manual on self-settinq binders'

Jan 1984

CMAT 53

M P SHAW Investigation into the melting behaviour of an aluminium alloy

Nov 1983

CMAT 109

I SIGALAS & L PRETORIUS Ferrosilicon I

Nov 1983

CMAT 43

I SIGALAS 6 L PRETORIUS Ferrosilicon I I

Nov 1983

CMAT 44

I SIGALAS, J PIERRUS, J AURET 4 A VLACHOS Oebid Quarterly Report

Sep 1983

I SIGALAS, J PIERRUS & J AURET Oebfd Quarterly Report

Dec/Oes 1983

I SIGALAS, J PIERRUS & J AURET Oebid Quarterly Report

Apr 1984

CMAT 38

CMAT 48

CMAT 85

I SIGALAS Report on overseas visit to Sweden and fie UK (Oct 1983)

Jun 1984

I SIGALAS Report on the worki g group on materials properties

requests for the NIMR - an updating Jun 1984

IMAT 27

SMAT 16

C M STAMDER SMAT 14 Retort on motivation for acquisition of multi-technique surface

characterization equipment Jun 1984

C M STANDER i H G C HUMAN SMAT 10 Extension of wet chemical analysis fac i l i t i es at the National Institute

for Materials Research Jun 1984

R J STEAD & A I KINGON CMAT 83 Report on the preparation of magnesium oxide stablized Zr0 2

Apr 1984

A P STcVENS CMAT 78 Metallurgical investiqations of fai led steel shaft

Mar 1984

A P STEVENS CMAT 87 Metallurgical investigation of a gear puller

Apr 1984

S W STEYN, P W RICHTER & S HART CMAT 17 Calcium oxalate monohydrate

Nov 1983

G F STEYN & R KAUERAUF CMAT 13 Report on sponsored research

Nov 1983

G F STEYN 6 N P YOUNG CMAT 12 Calibration system using pseudo-random white noise signals

Cct/Okt 1983

G F STEYN I R KAUERAUF CMAT 14 Report on sponsored research

Nov 1983

P J TERBLANCHé, P M MOLEFE i « t KINGON CMAT 33 Sponsored report on re-industrialization of the PZT-process

Oct/Okt 1983

M M THACKERAY IMAT 35 Report on overseas v is i t , UK & France

Apr 1 34

M N .1 VAN DEN BERG, R H AitfREWS & W DRIJFHOUT CMAT 5 Sponsored report on tube development

Auq 1983

U N H VAN DEN BERG, W DRIJFHOUT & R H ANOREWS CMAT 58 Sponsored report on tube development

Feb 1984

J VERMEULEN, I GOEDEKE & S HART CMAT 55 Finite element analysis of piezoelectric materials

Jan 1984

N M WALTERS*, C J KOK* & C CLAASE NR!0 Optical properties of the South African marine environment Internal

Compiled in cooperation with the National Research Institute for report Oceanoloqy and the National Physical Research Laboratory

Mar 1984

J W WEGMAN « .DEC ROGERS IMAT 4 The design and construction of a high stabi l i ty maqnet power supply

for the Varian MAT SM1-BF mass spectrograph Nov 1983

B Z WEISS*** & J 1 MCQUEER CMAT 7 Investigation of breakaqes of f is t fastener d ips

Sep 1983

A WELLS CMAT 6 Surface heat treatments and coatings project. A review of the

South African situation Sep 1983

95. A HELLS CHAT 51 An investigation of three coated bar mill coolinq bed roller sleeves

Dec/Oes 1983

96. A WELLS CHAT 71 Recommendations for induction hardening of h<«ners

Mar 1984

97. K N HOODS, L 0 V GRANT, E D RAWSTHORNE, H J STRYOOM i W H GRIES SMAT 2 A d ig i t a l squarer system for posi t ive mass iden t i f i ca t i on on the ARL

ion microprote mass analyser Jan 1984

C O N F E R E N C E P R O C E E D I N G S r 0 N F I R E N S I E V E R R I G T I X G E

* Member of another i ns t i t u te or organization * Lid «an 'n ander ins t i tuu t of orqanisasie * * Work done before appointment as NIMR staf f * * V -k gedoen voor aanstel l inq as 'n NIMN

member pc.-ôneellid * * * V i s i t i ng sc ient is t *** Besoekende wetenskaplike

1 . H BOOYENS & J H BASSON Semiconductor materials research at the NIMR

P»oc. 1st CSIR (ROSA) - NSC (ROC) Silane Workshop (1983), 52

2. A P BENTLEY Microstructural studies of Fe-Mn-AI al loys

Proc. 1st CÍ.IR (ROSA) - NSC (ROC) Metal Alloys and Ceramics Workshop (1983), 93

3. A P BENTLEY Formaiior. of an ordered phase in Fe-Mn-AI a l loys

Proc. Electron Microsc. Soc. South. A f r . , 13 (1983), 27

4 . J B CLARK Overview of materials research in South Afr ica

Proc. 1st CSIR (ROSA) - (NCS (ROC) Metal Alloys and Ceramics Workshop (1983), 11

5. I B CLARK Strategic materials, a foreign viewpoint

Proc. 7th Biennial conference on National Materials policy. Commission on Science and Technology. U.S. House of Representatives. 95th Congress (1983), 55

6. NR COMINS Structures of ordered l inear dis locat ion multipoles in Cu-Al a l loys

Proc. 1st SCIR (ROSA) - NSC (ROC) Metal Alloys and Ceramics Workshop (1983), 15

7. J H DALTON Heat resistant a l loy research at the CSIR

Proc. 1st CSIR (ROSA) - NCS (ROC) Metal Ulloys and Ceramics Workshop (1983), 121

8. H FIDOS Volume chanqes during the solidification of ductile iron

Proc. 51st Int. Foundry Cong., Lisbon (1984), No. 8

9. J T FOURIE & N R COMINS Surface p l a s t i c i t y effects in single crystals of pure metal, of solut ion hardened a l loy

and of dispersion hardened a l loy Proc. 1st CSIR (ROSA) - NSC (ROC) Metal Alloys and Ceramics Horkshop (1983), 67

10. S HART Optical materials and the i r equation of state

Proc. 1st CSIR (ROSA) - NSC (ROC) Metal Alloys and Ceramics Workshop, Taiwan, (1983), 221

11. 0 E JESSON An invest igat ion of stacking fau l t s in layer compounds usino convergent beam electron d i f f r ac t i on

Proc. Electron Microsc. Soc. South. A f r . , 13 (1983), 33

12. A I KINGON, R J STEAD & J B CLARK Structural ceramics with special emphasis on Zr0 2

Proc. 1st CSIR (ROSA) - NSC (ROC) Metal Alloys and Ceramic. Workshop, Taiwan (1983), 285

108

M P SHAW, F BLUM fc N R COHINS Observations and transformation induced dis locat ion d is t r ibu t ions and microstructural

ef fects in dual-phase steels Proc. Electron Microsc. Soc. South. Afr . , 13 (1983), 45

M P SHAH, F BLUM & N R COMINS The influence of microstructure on work-hardening behaviour in 3CR12 dual-phase steels

Proc. 1st Int. 3CR12 Conf., Johannesburg, (1984), 21

L E C T U R E S L E S I N 6 S

INTERNATIONAL CONFERENCES INTERNASIONALE KONFERENSIES

A P BENTLEY Microstructural studies of Fe-Mn-Al al loys

1st CSIR (ROSA)-NSC (ROC) Metal Alloys and CeramK» Workshop Aug/Sep 1983

H BOOYENS Semiconductor materials research at the NIMR-CSIR

Nat. Tsing Hua Univ. Hsin-Chu, Taiwan Aug 1983

H BOOYENS Studies of compound semiconductors at the N1MR

RSA-ROC Workshop on Semiconductor Materials Research, Pretor ia May/Mei 1984

J B CLARK Overview of Materials Research in South Africa

1st CSIR (ROSA) - NSC (ROC) Metal Alloys and Ceramics Workshop Aug/Sep 1983

J B CLARK Strategic materials, a foreign viewpoint

7th Biennial Conference on National Materials Policy. Commission on Science and Technology. U.S. House of Representatives. 95th Congress

1983 N R COMINS

Structures of ordered l inear dis locat ion multipoles in Cu-Al a l loys 1st CSIR (ROSA)-NSC (ROC) Metal Alloys and Ceramics Workshop

Aug/Sep 1983

J H OALTON Heat resistant alloy research at the CSIR

1st CSIR (ROSA)-NSC (ROC) Metal Alloys and Ceramics Workshop Aug/Sep 1983

H FIDOS Volume changes during the solidification of ductile iron

5! i. International Foundry Congress, Lisbon Jun 1984

0 T FOURIE & N R COMINS Surface plasticity effects in single crystals of pure metal, of solution hardened

alloy and of dispersion hardened alloy 1st CSIR (ROSA) - NSC (ROC) Metal Alloys and Ceramics Workshop

Auq/Sep 1983 0 GOLDMAN, S HART, J 8 CLARK & E GUTMANAS*

Effect of heat treatment in reducing atmospheres on cold sintering of high speed steel International Powder Metallurgy Conference, Toronto

Jun 1984

11. 0 8 GOLDMAN, E Y GUTMANAS*, I SCHEFFER I 0 ZAK Effect of heat treatment in reducing atmosphere on properties of cold sintered meta' powders

2nd Israel Materials Engineering Conference, Beershewa, Israel Feb 1984

12. S HAR-Pressure var iat ion of the e las t ic moduli of the sodium h a l v e s

IXth Airapt Conference, Albany, Hew York 1983

13. H S C HUMAN, J A STRAUSS * N K FERREIRA A boosted glow discharge source and atonic fluorimeter detector for the analysis of metals

CS1 XXIII, Amsterdam Jun - Jul 1983

14. N OMENETTO*, H G C HUMAN, P CAVALLI* l 6 ROSSI* Electrothermal atomizers as resonance monoch» omators for ICP emission spectrometry

CSI XXIII, Ansterdam Jun - Jul 1983

15. N OMENETTO*, H G C HUMAN, P CAVALLI* & G ROSSI* Laser excited ICP fluorescence: Analytical or diagnostical tool?

GSI XXIII, Amsterdam Jun - Jul 1983

16. MP SHAW, F BLUM & N R COMINS The influence of microstructure on work-harden ir.g behaviour in 3CR12 dual -phase steels

1st International 3CR12 Conference, Johannesburg Mar 1984

17. I SIGALAS, A VLACHOS t. S HART Shear strength of several ceramic materials and graphite at high temperatures and pressures

IX Airapt Conference, Albany, New York 1983

18. M M THACKERAY, W I F DAVID*, P G BRUCE* & J B GOODENOUGH* Lithium insert ion into the spinel structure

4th Internat ional Conference on Solid State Ion ics, Grenoble, France Jul 1983

19. M M THACKERAY, P J JOHNSON*, L A DE PIOCCIO.TO, W I F OAVID*. P G 8RUCE* 4 J B GOODENOUGH* Electrochemical and structural characterization of LiMnjO., cathodes

in room temperature l i th ium ce l ls 2nd International Meeting on Lithium Bat ter ies , Par is , France

Apr 1984

NATIONAL CONFERENCES NASIONM.E KONFERENSIES

1 . J G AURET 4 I SIGALAS Compaction studies of ceramic powders

South African Ins t i tu te of Physics 29th Annual Conference, Cape Town Jul 1984

2. J H BASSON A C B MILLS The Hall ef fect of HgCdTe

South African Ins t i t u te of Physics 29th Annual Conference, Cape Town Jul 1984

3. A P BENTLEY Formation of an ordered phase in Fe-Mn-Al al loys

Electron Microscopy Society of Southern Af r ica - 22nd Conference Nov - Dec/Oes 1983

4 . A P BOTHA The growth of compound semiconductors by MOCVD

South African Institute cf Physics 29th Annual conference, Cape Town Jul 1984

110

C J BOTHA The bulk crystal growth of Hg,_xCdxTe by the quench-annea? technique

Conference on Crystal Growth. Pretoria Nov 1983

C J BOTHA Quench-anneal grown Hg 1. xCd ) tTe

South African Institute of Physics 29th Annual Conference, Cape Town Jul 1984

R BROWN I I SIGALAS Thermal conductivity of CaF2 as a fmction of pressure

South African Institute o* Physics 29th Annual Conference, Cape Town Jul 1984

C CLAASE Implementering van die rekenaarheheerde pclichromator vir opneen van spektra

SA Spektroskopiere Vereniqing Simposium, Pretoria Apr 1984

J B CLARK Openinq address

Conference on Crystal growth, Pretoria Nov 1983

C M DENANET Electronic structure of UXi,L2 and analogs: An XPS comparative study

South African Chemical Institute - 28th Convention, Stellenbosch Jan 1984

0 R 0£ VIUIERS, M A RES * R 0 HECKROOOT* Na 2 0-8 2 0 3 -Si0 2 glasses doped with Nd 20 3

South African Institute of Physics, 29th Annual Conference, Cape Town Jul 1984

N P FERREIRA, J A STRAUSS 1 I L VAN MAARSEVEEH Dataprosesserinq vir die Paschen-Runqe spektrometer

Suid-Afrikaanse Spefctroskopiese Vereniqinq Simposium, Pretoria Apr 1984

B J FITZPATRICK* ( R J MUUER Proposed liauid phase epitaxial (LPE) growth of Hq, C ^ T e

Conference on Crystal Growth, Pretoria Nov 1983 J T FOURIE

Advanced materials characterization Materials Symposium, CSIR

Nov 1983

S HART Hiqh te.itperature melt growth of halides Conference on Crystal Growth, Pretoria

Nov 1983

D E JESSON An investiqation of stackinq faults in layer compounds usinq converqent beam

electron diffraction Electron Microscopy Society of Southern Africa, Johannesburq

Oec/Oes 1983

0 S JONES Overview of analytical functions in mass spectrometry

South African Association for Mass Spectrometry, Johannesburq Nov 1983

A I K1NG0N Ceramics processing research

Materials Symposium, CSIR Nov 1983

19. A I KINGON I R J STEAD Chemistry and phase behaviour of ZrOj for ceramic applications

Inorganic '83, SA Chemical Institute, Rustenburq Jul 1983

20. A I KINGON & P J TERBLANCHé Effect of defects on properties of PZT ferroelectric ceramics

The Defect Solid State 84, Cape Town Jul 1984

21. B LILLICRAP* & A I KINGON Growth of larqe single crystals of ammonium dihydrogen phosphate

Conference on Crystal Growth, CSIR Nov 1983

22. C B MILLS, H C SNYMAN* ( F D AURET* Anomalies in the C - V characteristic of GaAs MOS structures


23. R J MULLER, J H BASSON & H BOOYENS Some considerations on the growth of (HqCd)Te by liquid phase epitaxy South African Institute oi Physics 29th Annual Conference, Cape Town

Jul 1984 24. V A NICHOLAS & A I KINGON

Compositional variation within the Nasi con solid solution The Defect Solid State 84, Cape Town

Jul 1984

25. V A NICHOLAS, J B CLARK & A I KINGON High temperature chemistry of N a ^ - Z ^ i ^ ^ O ^ solid electrolytes

Inorganic '83, SA Chemical Inst i tute, Rustenburg Jul 1983

26. V A NICHOLAS, G F STEYN & A I KINGON Sodium ion conductivity tests for the Nasicon solid electrolyte


27. E NORVAL Pirolities bedekte grafietbuise vir gebruik in grafietoond - AA spektrometrie

en sekere toepassings Die Suid-Afrlkaanse Chemiese Instituut - 28ste Konvensie, Stellenbosch

Jan 1984 28. S D OLSEN

Standardization of white cast iron by ICP emission spectroscopy South African Spectroscopic Society Symposium, Pretoria

Apr 1984 29. J PIERRUS & I SIGALAS

Pressure dependence of the thermal conductivity of several selected alkali halides South African Institute of Physics 29th Annual Conference, Cape Town

Jul 1984

30. D E C ROGERS & D S JONES High precision mass spectrography of electronic materials

The South African Chemical Institute - 28th Convention, Stellenbosch Feb 1984

31. M P SHAW, F BLUM & N R COMINS Observations on transformation induced dislocation distributions and microstructural

effects in dual-phase steels Electron Microscopy Society of Southern Africa - 22nd Conference

Nov - Dec/Des 1983 32. I SIGALAS, J G AURET & S HART

Compressibility of one glass and two glass ceramics up to 4 GPa South African Institute of Physics 29tn Annual Conference, Cape Town

Jul 1984

112

I SISALAS, B HOKENSSON* * P ANOERSSON* Thermal conductivity of NaBr as a function of pressure and temperature

as measured by the hot wire method South African Institute of Physics 29th Annual Conference. Cape Town

Jul 1984 R J STEAD t A I KINGON

High wemperatjre phase behaviour and toughening in stabilized zirconia South Africen Institute of Physics 29th Annual Conference, Cape Town

Jul 1984 H N THACKERAY, W I F DAVID*, P b BRUCE* 1 J B 600DENOUGH*

Solid solution electrodes: Lithium insertion into oxospinel Inorganic '83, SA Chemical Institute, Rustenburg

Jul 1983 M N THACKERY. P J JOHNSON*. L A DE PICCIOTTO, H I F DAVID*. P 6 BRUCE* & J B GOODENOUGH*

Insertion/extraction of lithium into/from the spinel LiMnjOi, The Defect Solid State 84, Cape Town

Jul 1984 M M THACKERAY, L A OE PICCIOTTO, U I F DAVID*, P G BRUCE* t J B GOODENOUGH*

Lithium insertion into oxo-spinels South African Chemical Institute - 28th Convention, Stellenbosch

Jan 1984 G VEKINIS

X-ray stress analysis of the residual stress in pre-compressed MC-6t Co South African Institute of Physics 29th Annual Conference, Cape Town

Jul 1984

A VLACHOS 6 I SIGALAS Shear strength of several materials as a function of pressure and temperature


A J WILLIS Semiconductor contact resistance studies


SUNDRY LECTURES ANDER LESINGS

H BOOYENS Halfqeleier materiale

Universiteit van die Oranje Vrystaat, Bloemfontein Mar 1984 J B CLARK

Recent NIMR research highliqhts in association with S2*3 Material Colloouium, University of Cape Town

Oct/Okt 1983 J B CLARK

Recent NIMR research hiqhliqhts in association with S 2A 3

Physics Colloquium, University of Port Elizabeth Oct/Okt 1983

J B CLARK Recent NIMR research highlights in association with S2A3

Chemistry Colloquium, University of Natal (Durban) Oct/Okt 1983

J B CLARK Recent NIMR research highlights in association with S2A3

Physics Colloquium, University of Stellenbosch Oct/Okt 1983

J B CLARK Recent NIMR research highlights in association with S 2A 3

Physics Colloquium, University of the Witwatersrand May/Mei 1984

7. J B CLARK Recent NINt research highlights in association with SÂ.

NPRL Colloquium Jun 1984

8. S HART Recent developments at the NIHR

Physics Colloquium, University of Cape Town Feb 1984

9. S HART High pressure physics and the equation of state

Physics Colloquium, University of the Witwatersrand Apr 1984

10. A I KINGM Research and development of special ceramics in South A'rica

Tokyo Institute of Technology, Tokyo, Japan Sep 1983

11. A I KINGON Course on 'Phase Studies'

Presented to chemical engineering students. University of the Witwatersrand Apr 1984

12 P H RICHTER X-ray diffraction course

Presenter" to 4th year chemistry students. University of Pretoria May/Mei 1984

13. Y SENTARLI Solidification of commercially important alloys SA1F Lecture: Understanding Foundry Technology

Oct/Okt 1983

14. M P SHAW Appli:ations of converqent beam electron diffraction to phase transforation in metals

Department of Metallurgy ( Materials, University of Cape Town Jan 1984

15. I SI GALAS A plane wave method for measuring the thermal conductivity of dielectric materials at hiqh pressure

University of Umea, Sweden 0ct/0kt 19<?3

16. I SIGALAS Physics at high pressure

A seven lecture postgraduate course, University of the Witwatersrand Jul 1984

17. J T THIRLWALL Aspects of energy dispersive X-ray analysis

Three lectures, School for Scanning Electron Microscopy, University of Cape Town Jan 1984

18. A WELLS Plasma heat treatment

Understanding Heat Treatment Course, University of the Witwatersrand Sep 1983

19. A WELLS Vapour deposition of metallurgical coatings: An introduction to the technology

SAIF Specialist Heat Treatment Oivislon Aug 1983

20. A WELLS Plasma heat treatment

Heat Treatment for Engineers Course, University of the Witwatersrand Nov 1983

21. A WELLS Vapour deposition of metallurgical coatings: An introduction to the technology

Golden Reef Branch, American Electroplaters' Society, Johannesburg Jun 1984

114

WORKING GROUPS, COMMITTEES, COLLOQUIA AND VISITS

MERKGROEPE, KOHITEES, COLLOOUIA EN BESOEKE

H O R k l l G G R O U P R E C O H H E H -D AT I 0 R S

J T FOUR IE M A COHINS

Analytical electron Microscope

June 1984

The resul ts of a number of national surveys on

the need of electron microscopy instrumenta

t ion in South Afr ica were investigated. I t

Mas concluded that the complexity of projects

at nine of the foremost materials research

centres is such that decentralized I K kV

f a c i l i t i e s in analyt ical electron microscopy

are required, preferably at each of those

centres. Par t i cu la r l y the NIMR, because of

i t s many a c t i v i t i e s in materials research,

f inds i t se l f in an extremely vulnerable s i tua

t ion without e f fec t ive analyt ical electron

microscopy f a c i l i t i e s . A thorouqh descript ion

of the capab i l i t ies of analyt ical electron

microscopes is given in the report (SMAT 15)

to emphasize the importance of acquiring such

instruments.

Recommendation

I t is recommended that an analyt ical electron

microscope should be purchased for the NIMR at

the ear l iest possible opportunity.

J H DALTON

Cerate mould laboratory

May 1984

The Working Group investigated the require

ments for research and development in the

f i e l d of ceramic mould» to be used in the

local investment castinq industry for produc

t ion of high precis ion, high qual i ty castings.

U E R K G R O E P - A A H B E V E L I R G S

J T FOURIE I N R CCMINS

Anal H i e s * elektromrikroskoop

Junie 1984

Die u i ts lag van "n aantal nasionale opnames

oor die behoefte aan elektromnikroskopie-

instrumentasie in Suid-Afrika is ondersoek.

Die gevolgtrekking is dat die projekte by nege

van die vooraanstaande materiaalnavorsing-

sentra so kompleks is dat gedesentraliseerde

120 k V - f a s i l i t e i t e v i r a.:a1itiese e lektron-

mikroskopie vereis word en dat elke sentrum

verk ies l ik 'n eie f a s i l i t e i t moet hê. In die

besonder is die NIMN as gevolq van sy vee lvu l -

diqe ak t iw i te i te in materiaalnavorsing baie

kwesbaar sonder doeltreffende anal i t iese elek-

t ronmikroskop ie- fas i l i te i te 'n Deeglike be-

skrywina van die vermoéns van anal i t iese elek-

tronmikroskope word in die verslag (;MAT 15)

gegee ten einde die belangrikheid vai die ver-

kryging van sodanige instrumente te beklem-

toon.

Aanbeveling

Daar word aanbeveel dat 'n anal i t iese elek-

tronmikroskoop by die eerste moontlike

geleentheid v i r die NIMN aanqekoop word.

J H DALTON

Keraaiekgietvomlaboratorium

Mei 1984

Die Werkgroep het ondersoek ingestel na die

vereistes v i r navorsing en ontwikkeling op die

gebfed van keramiekgietvorms v i r gebruik in

die plaasl ike presisiegietnywerhetd v i r die

produksle van hoé-akkuraatheld, hoé-kwal i tei t

gietstukke.

1,1 ,S

Recommendation Aanbevelings

• A Ceramic Mould Laboratory, suitably equipped and staffed, should be established within the Metals Division of the NIMR. This laboratory should carry out research work into the design, processing and quality aspects of êramic shell mould manufacture to be used in the investment casting process.

• The major aims of the ceramic mould laboratory should be

••to provide an expertise base for local industry in the field of investment casting

••to provide a service to local industry, including produi rs, end-users and mite-rials suppliers by

- diverse problem solving - providinq testing, development an!

pilot-run facilities for trial castings

- providing a contact between consumer and end-user

- aiding in determining quality assurance and control guidelines

- acting as a centre for the collection, investigation and dissemination of data in the literature on investment casting

- fostering international relationships and contacts in the field.

• It is felt that the ceramic mould laboratory should also provide an educational function by taking a leadinq role in forming a local association for investment castinq. This association should provide a forum for a better understanding of the process by orqanizinq seminars and discussions on the subject to incorporate as wide as possible an audience from all branches of local industry.

• 'n Keramiekgietvormlaboratorium, met die nodiqe toerusting en personeel behoort in die Afdeling Met ale van die NIMN gevestig te word. Die laboratoriurn behoort navor-sing oor die ontwerp, prosessering en kwa-liteitsaspekte van die vervaardiginq van keramiekdopgietvorms vir die presisiegie-tingsproses te onderneem.

• Die belangrikste oogmerke van die keramiek-gietvormlaboratorium behoort te wees

•• om "n deeglike kundigheidsbasis vir die plaaslike nywerheid op die gebied van presisiegieting te skep

•• om 'n diens te lewer aan plaaslike ny-werhede, insluitende verskaffers, eind-geb.jikors en materiaalverskaffers deur

- diverse prohleemoplossing - die verskaffing van toets-, ontwikke-

ling- en toetsloop-fasiliteite vir proefgietinqs

- te dien as tussenganger tussen ver-bruiker en eindqebruiker

- te help met die vasstel van kwali-teitsversekering- en kontroleriglyne

- te dien as 'n sentrum vir die insame-ling, ondersoek en verspreiding van data in die literatuur oor presisie-gieting

- die uitbou van interna*ionale verhou-dings en kontrakte op die gebied.

• Die roening is dat die keramiekgietvormlaboratorium 'n opvoedingsfunksie behoort te onderneem, deur 'n leidende rol te neem in die vorming van 'n plaaslike vereniging vir presisiegieting. Hierdie vereniqinq behoort 'n forum te bied vir beter begrip van die proses deur die reel van seminare en besprekinqs oor die onderwerp en om so 'n bree qehoor as moontlik uit alle vertak-kings van die plaaslike nywerheid te inkor-poreer.

116

5 HART

Crystal growing

June 1984

Evidence gathered from a recent Crystal Growth

Conference at the CSIR, overseas consultants,

a widely c irculated questionnaire and a work-

inq group shows that there is a major gap in

the country's capabi l i ty in materials process

ing. Thi. is in sinqle crystal qrowth from

the hiqr temperature melt. Such systems

account for about 90% of the world-wide pro

duction of bulk single crystals and can be

used to address a var ie ty of p-oblems for un i

vers i ty sc ien t i s ts , ins t i tu t ions and industry

in South Afr ica both present and fu ture. The

benefits of a centra) crystal growth unit w i l l

be to release sc ient is ts who at present are

forced to devote much of the i r time to produc

ing sample material and to provide a broad

bas^d dedicated expertise base for increasinq

national needs in opt ics , metals and e lect ron

ics .

In addit ion to t h i s , s taf f are urgently re

quired to expand the ac t i v i t i e s on epi tax ia l

growth techniques at present beinq established

at the NÍMR. Such techniques are rapidly

emerqmg as of great importance in semi conduc

t ing applications.

Recommendation

Funding is therefore recommended for six

posts, three of which w i l l bo used to estab

l i sh the high temperature melt laboratory and

three for epi taxial methods.

Capital equipment is reouired to provide a

central f a c i l i t y for melt qrowth of c rys ta ls ,

includinq heating systems, at a to ta l cost of

R300 000.

S HART

Kristalgroei

Junie 1984

Oit blyk u i t i n l i g t i n g wat tydens 'n onlanqse

Kristalqroeikonferensie t y die WNNR, van oor-

sese konsultante, 'n wyd gesirkvleerde vraelys

en 'n werkqroep ingewin i s , dat 'n qr jot leem-

te ten opsiqte van d ie land se materiaalpro-

sesseringsvermoê' bestaan, met betrekking to t

die groei van enke lk r i s ta l l e u i t 'n hoe-tempe-

ratuur smelt. Onqeveer 90% van die wêreldpro-

duksie van grootmaat enkelkr istalmater iale

word deur h ierd ie prosesse geproduseer en d i t

kan ten opsigte van 'n verskeidenheid huidige

en toekomstige probleme van univers i te i tswe-

tenskaplikes, organisasies en die nywerheid in

Suid-Afrika aangewend word. Die voordele van

'n sentrale kr is ta lqroei-eenheid is dat d i t

die taak van die wetenskaplike* wat tans ge-

noodsaak is om hul tyd te bestee om mater iaal-

monsters te produseer, baie s i l verqemaklik.

'n Spesifieke kundigheidsbasis sal op 'n wye

front in die toenemende nasionale behoefte in

die opt ika, metaalkunde en elektronika voor-

s icn.

Verder bestaan 'r. drinqende behoefte aan per-

soneel om die bedrywighede op epi taksiele

qroeiteqnieke wat tans by die NIMN qevestig

word, u i t te b r e i . Hierdie tegnieke word toe-

nemend belangrik in die toepassinq van hal foe-

l e ie rs .

Aanbeveliiiq

Oaar word dus aanbeveel dat fondse beskiktaar

qestel word v i r ses poste, waarvan dr ie v i r

die vest iqlnq van 'n hoé-temper at uur smelt-

labor atorium, en dr ie v i r epi taksiële metodes

qebruik sal word.

KapitaaHoerustinq met 'n to ta le koste van

R300 000 sal benodiq word v i r die verskaff ing

van 'n sentrale f a ^ i l i t e i t , met die i ns lu i t i nq

van verh i t t i ngs i ' teme, v i r die qroei van k r i -

s ta l le u i t die smelt.

117

S HART

Refractories June 1984

Discissions have been concluded recently with representatives of the main suppli T S and users of refractor ies in South A f r i ca . These, together with information qained by «ay of Questionnaire sheets and f indinqs of a workinq group organized in 1983 by the National Mater i a l s Programme of CSP show that there is a great need for « concerted e f fo r t bu i ld up expert ise in new ref ractory materials and the i r engineering. The world-wide trends to «ore sophisticated metal lurgical treatments are having major implications in the types of re f rac tory materials required and South Afr ica is in danger of beinq driven to qreater dependence on overseas supply and licence agreements. The HIM» is well placed to expand i ts expertise base to the SA ref ractor ies indust r i e s . Such an i n i t i a t i v e w i l l help to avoid excessive dependence on overseas supply «id w i l l have lonq term economic advantages for the country.

Recommendation

I t is recommended that tnree posts (two fo r research and one technical) be established. The s ta f f members recrui ted to these posts should provide an expertise in new refractory materials and thei r engineering. Emphasis should be placed on explo i t inq local re sources, such as zirconia which is beinq reimport ed into th is country in processed form.

Capital funds to support th is a c t i v i t y are estimated at R150 000. Hiqh temperature k i ln ' , are required, as well »s equipment for hiqf temperature creep, modu'js of rupture, ponder preparation and powder pressing.

S HART

Vuurvaste aateriaal Junie 1984

Samesprekinqs is onlanqs met verteenwoordiqers van die belangrikste verskaffers en qebruikers van vuurvaste materiale in Suid-Afr ika gevoer. O i t , tesame aet i n l i g t i m j wat by wyse van ' r landswye vraelyste ingewin i s , asook bevindiqe van 'n werksgroep wat qedurende 1982 dew die Nasionate Materiaalprtqraame van KUP georqani-seer i s , toon die qroot behoefte aan 'n daad-werkl ike poqing on kundiqheid ten opsigte van nuwe vuurvaste materiaal en die gepaardgaande inqenieurskennis op te bou. Die neiginq na meer qesofist ikeerde metal lurgies* behande-l inqs net 'n sterk invloed op die t ipe vuur-vai te materiaal wat benodiq word en Suid-Af r ika verkeer dus in die qevaarlike s i tuas ie dat 'n qroter afhanklikheid van oorsese verskaffers en lisensiërinqsooreenkOKjte mag ont-staan. Oie *ÍWI verkeer in 'n gunstige pos i -s ie om bestaande kundiqheid na die Suid-Afrikaanse nywerheid vie vuurvaste m a t e r i a l u i t te b r e i . So 'n i n i s i a t i e f sal oormatige afhanklikheid van oorsese verskaffers help verhofo en sal ook ekonomiese voordele oor die lanq termyn v i r d ie land inhou.

Aanbevelinq

Daar word aanbeveel dat dr ie poste (twee v i r navorsing en een tegnies) geskep word. Die personeel wat v i r hierdie poste qewerf word behoort oor 'n ki.ndiqheid in nuwe vuurvaste materiaal en die aepaardqaande ingenic rswese te beskik. Die benutting van pl/»aslike hulp-bronne moet bekletntoon word. Sirkonia word byvoorbeeld tans in *n verwerkte vorm herinqe-voer.

Daar word beraan dat daar ongeveer R150 000 aan kapitaalfondrc benodig word om hierdie be-drywiqheH te ondersteun. Hoë-temperatuur-oorde en toerust inq v i r hoé'-temperatuur k ru ip , breukmodulus, poeiervoorbereidinq ei; poeier-saamdrukkinq ward benodig.

1'IR

I SIGALAS Materials properties requests for the

mm - an update June 1984

A great deal of progress has already been achieved concerning equipment requests. The manpower problem, particularly the technical level remains very acute. A number of new properties of materials activities are urgently needed.

Recommendation

Strong recommendation is made in support of the *tIMR proposal for a large increase in technical support personnel. This is the subject of a separate Category III motivation. A further two posts should be established in the Properties of Materials Section of the Ceramics, Glass and Phase Studies Division of the NIMR to develop i.ew measurement methods required for the Institute's materials development programmes and to support local industrial needs. Capital equipment amounting to R150 000 is necessary to establish facilities needed for optical, mechanical and maqnetic studies.

C CLAASE, A LOUW, C B MILLS, M E THOMAS & I Le R STRY00M

Electronic services In the NIMR June 1984

The general purpose of the Electronic Working Study Group is to promote contact and cooperation between the electronics personnel of the different divisions.

At this stage it is clear that

• electronic services are completely decentralized

• from time to time a temporary need for additional maintenance or development services arises In most divisions

I SIGALAS Versoefce ten opsitf'.e van die eienskappe van

•ater ia le in die NINN - *n bywerking Junie 1984

Aansienli<!e vordering i: qemaak ten opsigte van versoeke vir toeruscinq. Die mannekrag-probleem bly egter kritiek, veral op tegniese vlak. 'n Aantal nuwe aktiwiteite met betrek-king tot die eienskappe van mater 1 ale is dringend noodsaaklik.

Aanbeveling

'R Sterk aanbevelinq ter ondersteuning van die "'IMN-voorstel vir 'n groot toename in tegniese ondersteuninqopersoneel word gemaafc. Hierdie onderwerp is 'n aparte Kategorie-III motive-ring, 'n Verdere twf~~ poste behoort in die Seksie Eienskappe van Materiale van die Afde-linq Keramiek, Glas en Fasestudies in die NIMN geskep word om die nodige nuwe metinqsmetodes vir die Instituut se materiaalontwikkelings-programme te ontwikkel en ook die behoeftes van die plaaslike nywerheid t.e steun. Kapi-taaltoerusting ter waarde van R150 000 word benodig om die nodiqe fasiliteite vir die on-dersoeke van optiese, meganiese en magnetiese eienskappe te vestig.

C CLAASE, A LOUW, C B MILLS, M E THOMAS & I Le R STRYD0M

Elektroniese dienste in die NIMN Junie 1984

Die algemene oogmerke van die Elektroniese Werkstudiegroep 1s om kontak en samewerking tussen die elektronika-personeel in die onder-skeie afdelings te bewerkstellig.

Dit Is tans duldelik dat

• elektroniese dienste heeltemal qedesentra-liseer is

'n tydelike behoefte aan tussentydse byko-mende Instandhoudings- of ontwikkelIngs-dfenste in die meeste afdelinqs ontstaan

119

• no person in the Institute has e complete

overview of all the activities of the elec

tronics personnel, or of the apparatus

which they service.

The conclusion reached in the report (SMAT 17)

is that the existinq degree of decentraliza

tion is undesirable because important projects

become totally de-pendent on the services of a

few persons. This leads to a lack of continu

ity when such persons leave the service. The

situation prevents younger personnel acquirinq

experience in a broader field.

Recommendation

Since little information was available, pro

blems and needs are not fully described in

this report. It is recommended that a work

study programme under the leadership of all

the members of the Working Group and with the

cooperation of the project leaders, should be

launched immediately to determine the needs

for maintenance and development in the various

divisions.

Project leaders will be encouraqed to make

greater use of the existinq electronic ser

vices to improve laboratory efficiency.

C M STANDER & H G C HUMAN

Extension of wet chemical analysts facilities at the NIMR

June 1984

The necessity for expandinq the wet chemical

analysis f a c i l i t i e s in the Materials Charact

er izat ion Division has been examined by the

Working Group. The importance of wet chemical

analysis in analysinq secondary standards,

lesseninq samplino er rors , analysing occasion

al samples and increasinq analyt ical precision

and accuracy is stressed. In add i t ion, answers

to enquiries sent to a number of consultants

concerning the necessity for wet chemical

analysis and the requirements for an e f f i c ien t

analytical service are presented (SMAT 10).

With the help of these answers i t is concluded

that the wet chemical analysis f a c i l i t i e s

• qeeii persoon in die Ins t i tuu t 'n oorsig

net oor al die ak t iw i te i te van die elek-

tronikapersoneel of die app< ' * t wat deur

hul le in stand qehou word n i

In die versloq (SMAT 17] wed tot die qevolq-

trekkinq gekom dat die bestaande mate van de-

sentral isasie ongewens is aangesien belangrike

projekte totaal van d ie dienste van enkele

persone afhanklik i s . Dit l e i to t V gebrek

aan kontinu'f tei t wanneer h ierd ie persone die

diens ver laa t . Die s i tuasie verhinder ook dat

jonqer personeel oor 'n breë veld ondervindinq

opdoen.

Aanbevelinq

Probleme en behoeftes word nie in die verslaq

behoorlik omskryf nie omdat so min i n l i g t i n g

beskikbaar i s . Daar word wel aanbeveel dat 'n

werkstudieproqram onder le id inq van al die

lede van die Werkqroep met die samewerkinq van

die projekleiers onmiddellik van stapel ge-

stuur word on» die behoeftes aan instandhoudinq

en ontwikkelinq in die onderskeie afdelinqs te

p e i l .

Projekleiers sal aanQemoedig word om meer v^1

die bestaaride elektronikadienste gebruik te

maak om doellreffendheid in hul le laborato-

riums *.e verhooq.

C M STANDER ( H G C HUMAN

Ui tbre id imj van f a s i l i t e i t e v ir not cheaiese ontleding by die N1MN

Junie 1984

Die vereiste vir uitbreidinq van die nat che

miese ontled'nqsfasiliteite in die Afdeling

Materiaa'karakterisering is deur die Werkqroep

ondersoek. Die belanqrikheid van nat chemiese

ontledinq vir die analise van sekondêre stan-

daarde, die verminderinq van monsterneminqs-

foute, die ontleding van toevallige monsters,

en die verbeterinq van analitiese noukeuriq-

heid word beklemtoon. Voorts word antwoorde

wat op "avrae aan 'n aantal konsultante met

betrekkinq tot die behoefte aan nat chemiese

ontledinq en die vereistes van 'n doeltreffen-

de analitiese diens ontvan i is, gerapporteer

(SMAT 10). Ha aanleidinq van hierdie antwoorde

120

should be expanded with the object ive of sup

plying a complementary and supporting service

to the «xist inq instrumental methods of anal

ys is .

is to t die gevolgtrekkinq gekoffl dat die nat

chemiese on t l ed ings fas i l i t e i t e uitgebrei be-

hoort te word on 'n ondersteunende en aanvul-

lende diens to t die bestaande instrumentele

ontledinqsmetodes te verskaf.

Recommendat ion Aanbeveling

I t is recommended that

• a universi ty graduate with an appropriate

qua l i f i ca t ion be appointed as head of the

wet chemistry analyt ical laboratory

• two technical assistants be appointed

Oaar word aanbeveel dat

• 'n gegradueerde persoon met 'n toepaslike

kwa l i f i kas ie as hoof van die anal i t iese

laboratoriurn v i r nat chemie aangestel word

• twee teqniese assistente aangestel word

the wet chemistry laboratory be c losely i n

tegrated with the exist ing instrumental

analyt ical f a c i l i t i e s

daar 'n groot mate van integrasie tussen

die laboratorium v i r nat chemie en die be

staande instrumentele anal i t iese fas»1i-

t e i t e moet wees

a senior sc ient is t be given the task i f co

ordinating the instrumental and wet chem

i s t r y inalyt ical f a c i l i t i e s

die taak om die instrumentele en nat che

miese anal i t iese f a s i l i t e i t e te koordineer

aan 'n senior wetenjkaplike toevertrou word

the wet chemistry laboratory be a service

f a c i l i t y only and that any analyt ical pro

blems be solved with the help of the Analy

t i c a l Services D iv is ion , NCRL

die nat chemie laboratorium slegs 'n diens-

f a s i l i t e i t moet wees en dat anal i t iese pro-

bleme met die iiulp van die Afdeling Ana l i

t iese Dienste, NCNL, opgelos word

the appointed supervisor motivate for

equipment at an early stage.

die aangestelde toesfghouer op 'n vroeê'

stadium 'n motiverinq v i r toerustinq op-

s t e l .

N P FERREIRA, D E C ROGERS, J OALTON, 0 ORON, P W RICHTER, A I KINGON & A P 80THA

Materials characterization support for the NIMR

March 1983

N P FERREIRA, D E C ROGERS, J OALTON, 0 ORON, P W RICHTER, A I KINGON S A P BOTHA

Materlaalkarakterlserlngondersteunlng vir die NINN

Maart 1983

The report (IMAT 2) by the Worklnq Group on

Materials Character l.-ation services of the

NIMR contains the following:

Die verslag (IMAT 2) van die Werkgroep oor

Mater1aa1karakteriser1ngd1enste van die Naslo-

nale Instituut vir Materiaalnavorsing (NIMN)

bevat die volqende:

Determination of the nature and volume of

materials characterization services (chem

ical, physical and mechanical) required.

Attention is qlven to the requirements for

both routine and special services.

Bepallnq van die aard en volume van die

mater1aalkarakter1serinqdienste (enemies,

fisles en meqanies) wat vereis word. Aandag

word aan die verelstes vir belde roetlne-

en spesiale dienste q».gee.

• A review of the available characterization

f a c i l i t i e s of the NIK*.

• Findings regardinq the poss ib i l i t y of meet

ing requirements.

Sugqested solutions and recommendations r e

garding problem areas.

• Consideration of future collaboration be

tween div is ions of the NIMR.

Recommendation

A consensus on the ro le of the Materials

Character in t ion Division has been reached by

the working group. Pr imari ly the Divis ion

should have the fol lowing respons ib i l i t i es :

• Provision of chemical and analyt ical sup

port to a l l the div is ions wi th in the NIMR,

and where necessary to industry and organi

zations outside the NIMR.

• Research of an appl ied, developmental and

fundamental nature.

I t should be noted that research should per

form the fol lowing funct ions:

• Improve the qua l i t y of iraterâls character

izat ion support.

• Promote job sat is fac t ion for sc ien t i s t s ,

in order to reta in sc ien t i f i c s ta f f .

C M STANDER

Motivation for the acquisition of multi-technique surface characterization equipment

June 1984

The four main techniques used for surface

characterization i .e . X-ray photo-electron

spectroscopy, Auger-electron spectroscopy,

secondary ion mass spectroscopy and ion scat

ter ing spectroscopy are b r i e f l y described

(SMAT 14) and the i r ind ispens ib i l i t y for the

surface characterization of semiconductors,

• 'n Oorsiq van die beskikbare karakter ise-

r i n g s f a s i l i t e i t e van die NIMN.

• Bevindinqe oor die moontlikheid om aan ver-

eistes te voldoen.

Voorgestelde oplossings en aanbevelings in

verband met probleemqebiede.

• Oorweging van toekomstige samewerking tus-

sen afdelings van die NIMN.

Aanbeveling

Die werkqroep het ooreenstemming bereik oor

die ro l van die Afdel ing Mater iaalkarakter ise-

r i n q . In die eerste plek behoort die Afdeling

die volgende verantwoordelikhede te hê:

• Voorsiening van chemiese en anal i t iese on-

dersteuning aan al die afdelings van die

NIMN en waar nodig aan die nywerheid en

organisasies bui te die NIMN.

• Navorsing van fundamentele, toegepaste en

ontwikkelingsaard.

Oit behoort in gedagte gehou te word dat na

vorsing die volgende funksies moet vervul :

• Verbetering in die kwa l i te i t van mater iaal-

karakteriseringondersteuninq.

• Bevordering van werksbevrediqing v i r die

wetenskaplikes, ten einde wetenskaplike

personeel te behou.

C MSTAUDCR Hotlverlng vir die aanskaf van multitegniek-

toerusting vir karakteriserlng van oppervlakfce

Junie 1984

Die vier belanqrikste tegnieke v i r oppervlak-

karakter lser lng, te wete X-straal fotoëlek-

tronspektroskopie, Auqer elektron-spektrosko-

pie, sekondêre-ioon-massaspektroskopie en

ioonverstrooifnqspektroskopie, word ko r t l i k s

beskryf (SMAT 14) en die onontbeerlikheid van

qenoemde teqnieke v i r oppervlakkarakteriserinq

12?

metals, glasses, ceramics ano polymers emphasized. The importance of havinq one mu l t i -technique instrument for surface characterizat ion instead of a number of single technique instruments is discussed and the necessity of replacing the present aging instruments stressed. I t is concluded that a mu l t i - technique instrument is necessarv n the Surface Science Section to advance the present programme on semiconductor surface cleaning and to do e f f i c i en t surface and interface character iza t ion in metals. Acquisit ion of such an instrument is also necessary for future surface characterization of corrosion 1 'jers and polymer surfaces. I t i_. recommended that the required equipment be purchased and used in cooperative programmes on semiconductor and metal surfaces.

van ha i fqe ie ie rs , metale, qlassoorte, keramie-ke en pollmere word benadruk. Die belangrik-heid van een multiteqniek-instrument in plaas van 'n aantal enkeltegniek-instrumente v i r oppervlakkarakterisering word bespreek en die noodsaaklikheid om die huidige verouderde instrumente te vervanq, word beklemtoon. Die gevolgtrekking is gemaak dat *n mult i tegniek-instrument in die Oppervlakwetenskapseksie nodig is v i r die bevordering van die huidige program oor halfgeleier-oppervlaksuiwerinq en v i r doeltreffende oppervlak- en tussenvlak-karakter iser ing van metale. Die aanskaf van so 'n instrument is ook nodig v i r toekomstige oppervlakkarakterisering van korrostelae en polimeeroppervlakke. Daar word aanbeveel dat die nodiqe toerust ing aangekoop en gebruik word v i r kooperatiewe programme oor hal fqe-l e i e r - en metaaloppervlakke.

Recommendation Aanbevelinq

I t is recommended that a LHS 10 mu l t i - techn i que surface characterizat ion unit with XPS, AES, SIMS and ISS f a c i l i t i e s be purchased from Leybold-Heraeus GmbH, Cologne, Germany. The capi ta l required is as fo l lows:

Dit word aanbeveel dat 'n LHS 10-mult i tegniek-oppervlakkarakteriseringseenheid met XFS-, AES-, SIMS- en ISS - fas i l i t e i t e van Leybold-Heraeus GmbH, Keulen, Duitsland aangekoop word. Die nodiqe kapitaal is soos volq saam-gestel :

Basic instrument Data system Acces sories

10* GST

Total

R374 060 Basiese instrument R i l l 250 Oatastelsel R 18 500 Bybehore

R503 810 R 50 381 10« AVB

R554 191 Totaal

R374 060 R i l l 250 R 18 500

R503 810 R 50 381

R554 191

I t is recommended that in addition to the present proqramme on semiconductor surfaces a programme supportinq the ac t i v i t i e s of the Metals Division in either the corrosion or boundary segregation f i e l ds be i n i t i a t ed i f the LHS 10 unit request»* above is acquired.

Oaar word aanbeveel dat indien bogenoemde LHS 10-eenheid soos versoek, aanqeskaf word, daar bykomend tot die huidige program oor halfge-leier-oppervlakke, 'n program ter ondersteu-ninq van die ak t iw i te i te van die Afdeling Metale, of op die gebied van korrosie of op die van qrensseqreqasie in werking qestel word.

A R HARDING Rapid solidification processing

June 1984

Rapid So l id i f i ca t ion Processing (RSP), having

grown very quickly to incorporate many

A R HARDING Snelstol1ing-prosessering

Junie 1984

Snelstol l inq-prosesserinq (SSP) wat vinnig

ontwikkel het en baie kombinasies van s t o l l i n q

123

combinations of solidification and powder

techniques, has demonstrated that i t affords

the materials engineer the opportunity of

greatly extending the range of properties

obtainable from m.tallic materials.

Recommendat ion

The Working Group considered the developments

overseas and their significance for the needs

of South Africa. There was agreement that the

NIMR should

• acquire and maintain an awareness of devel

opments in RSP abroad

• develop an understanding of the science and

technology of RSP

• set up an experimental fac i l i ty to enable

the NIMR to do exploratory work and become

a centre of expertise.

The focus and objectives for the work should

be to identify topics and problems which have

particular relevance and potential for South

Africa, and not attempt merely to follow

developments in the rest of the world.

A staff of two research officers and one tech

nical officer should be appointed to undertake

this project.

- en poeier-tegnieke insluit het bewys dat dit

aan die materiaalingenieur die geleentheid

bied on die reeks van eienskappe wat vir

metaalmateriale verkry kan word baie te ver-

groot.

Aanbeveling

Die Uerkgroep het die buitelandse ontwikke-

ling en die belanq daarvan vir Suid-Afrika se

behoeftes in ag geneem. Daar was eenstemmiq-

heid dat die NIMH

• bewus word en bly van buitelandse ontwikke-

linge van SSP

• insig ontwikkel van die wetenskap en tegno-

logië van SSP

'n eksperimentele f a s i l i t e i t opstel om die

NIMN in staat te stel am ordersoeke te doen

en 'n sentrum van kundigheid te word.

Die fokus en doel van die werk moet wees om

probleme en onderwerpe te identifiseer wat be-

trekkinq het op, en van belang is vir Suid-

Afrika, en moet nie slegs ontwikkelinge in die

res van die wêreld volg nie.

Personeel bestaande uit twee navorscs en een

tegniese beampte behoort vir die projek aange-

stel te word.

m

V I S I T S A B R O A D

OR J H BASSO*

1 1 - 2 5 May 1984

USA

PURPOSE OF VISIT

• To attend the 1984 'US Workshop on the

Physics and Chemistry of Mercury Cadmium

Te l lu r ide ' at San Diego, Ca l i f o rn ia .

• To v i s i t a number of research organizations

and individuals in the USA involved in

electronic materials research.

CONCLUSIONS AND SUGGESTIONS

• I t is considered essential that one or

more persons from the NIMR attend the US

workshop on HgCdTe, which is held every

eighteen months, in order to gain access to

the latest available data on th is rap id ly

developing mater ial .

• In the f i e l d of semiconductor research,

the I I -V I ternary compound HqCdTe is a

re la t i ve newcomer and a large amount of

fundamental and empirical research has yet

to be done to gain a prope* understanding

of the materials propert ies. Publ icat ion

of results of research carr ied out at the

NIMR has led to improved communication with

the HgCdTe community and greater accessibi

l i t y to organizations involved in research

on the mater ia l .

• As a resul t of the poor oua l i ty CdTe sub

strates generally avai lable, as well as the

large densities of m is f i t dislocations typ

i c a l l y obtained at the interface between

the substrate and HqCdTe epi taxia l layer ,

much emphasis is being placed on the use of

a l ternat ive substrates such as ZnCdTe and

CdSeTe, as well as CdTe epi tax ia l layers

grown by metallo-organic chemical vapour

deposition (MOCVO). Since such material 1s

not commercially avai lable, the importance

of a local crystal growth e f fo r t to produce

O O R S E S E B E S O E K E

OR J H BASSO*

11 - 25 Mei 1984

VSA

OOEL VAN BESOEK

- 0* die 1984 'US Workshop on the Physics and

Chemistry of Mercury Cadmium Te l lu r ide ' te

San Diego, Ka l i fo rn ie by te woon.

• On 'n aantal navorsingsorganisasies en

individue in die VSA wat by elektroniese

materiaalnavorsing betrokke is te besoek.

GEVOLGTREKKINGS EN AANBEVELINGS

• Dit word as noodsaaklik beskou dat een of

meer persone van die NIMN die VSA-werkses-

sie oor HgCdTe wat elke agtien maande gehou

word, bywoon om sodoende toegang to t die

nuutste beskikbare i n l i g t i n g oor h ierd ie

vinnig-ontwikkelende materiaal te verkry.

• Op die gebien van halfgeleiernavorsing is

die I I -V I tornêre verbinding HgCdTe 'n

re l a t i e f iuwe aanlomeling en 'n groot hoe-

veelheid fundamentele en empiriese navor-

sing moet nog gedoen word om deeglike ins ig

in die eienskappe van die materiaal te ver

kry . Publikasie van resul tate van navor-

sing wat in die NIMN uitgevoer i s , het ge-

le i tot verbeterde kommunikasie met die

HqCdTe-gemeenskap en tot qroter toegankl ik-

heid tot organisasies wat by navorslng op

hierdie materiaal betrokke i s .

• As qevolq van die lae gehalte CdTe-substra-

te wat algemeen beskikbaar i s , sowel as die

groot digthede van wanpasontwrigtings wat

t ip ies by die tussenvlak tussen die sub-

straat en die HgCdTe epitaksiele lagie

verkry word, word groot nadruk tans op

alternatiewe substrate geplaas byvoorbeeld

ZnCdTe en CdSeTe, asook CdTe-ppitaksie'le

lagles wat deur metaal-organiese chemiese

dampneerslag (MOCVO) qegroei i s . Aangesien

hierdfe materiaal nie In die nandel beskik

baar is n ie , kan die belangrikheid van 'n

th i s material cannot be overemphasized.

• Much benefi t can be derived in the fu ture

by closer contact with Cornell Universi ty

in Ithaca, New York, whose School of Elec

t r i c a l Engineering is involved in the pro

duction of I I I -V materials by ep i tax ia l

growth tecnniques and the manufacture of

devices based on th is mater ia l .

Dft AP BOTHA

18 March - 15 Apr i l 1984

USA and UK

PURPOSE OF VISIT

• To study the technique of metallo-organic

chemical vapour deposition (MOCVO). Labo

rator ies operatinq MOCVD reactors were

v is i ted and a course at the Universi ty of

London, and an internat ional conference on

MOCVD held at Sheff ie ld Univers i ty , were

attended.


• MOCVD is a fast-growing technique which has

unique features such as the large scale

production of ep i tax ia l semiconductor lay

ers having good compositional and thickness

contro l .

• The explosion in the number of published

papers on th is subject shows a world-wide

expansion in in teres t .

• MOCVD is not only applied to the growth of

I I I -V semiconductors, but is also used to

grow 11-VI and IV-VI mater ia ls.

I t should prove advantageous to design and

bui ld » reactor rather than to buy a com

mercial model.

• A local proqramme on MOCVD should be s t a r t

ed as foon as possible as the f i e l d 1s ex

panding rap id ly .

126

p laasl ike kr is ta loroeipoqinq om h ierd ie

«ater iaal te produseer nie qenoeq beklem-

toon word n ie .

• Groot baat kan in die toekoms gevind word

deur nadere skakelinq met Cornell Univers i -

t e i t , I thaca, New York. Die Skool v i r

Elektr iese Inqenieurswese is betrokke by

die produksie van I I I -V materiale deur ep i -

taksië le groeitegnieke en die vervaardiginq

van toes te l le wat op hierdie materiaal ge-

baseer i s .

M A P BOTHA

18 Maart - 15 Apr i l 1984

VSA en VK

OOEL VAN BESOEK

• Om die tegniek van metaal-organiese chemie-

se dampneerslaq (MOCVD) te bestudeer.

Laboratoria wat MOCVD-reaktors bedryf, is

besoek en 'n kursus aan die Univers i te i t

van Londen asook "n intemasionale konfe-

rensie oor MOCVD is te Sheff ield Universi

t e i t bygewoon.


• MOCVD is 'n snelqroeiende tegniek met

unieke eienskappe soos die grootskaalse

produksie van epi taksiéïe hal fge le ier lag ies

met goeie samestell ing- en diktebeheer.

• Die ontp lo f f ing in die aantal publikasies

oor hierdie onderwerp toon wêreldwye toe-

name in be langste l l ing.

• MOCVD word nie a l leen l ik sleqs op die qroei

van I I I -V hal fqele iers toegepas n ie , maar

word ook gebruik om I I -V I en IV-VI mater i

ale te g roe i .

• Dit sou voordelig wees om 'n reaktor te

ontwerp en te bou eerder as om 'n handels-

model te koop.

• 'n Plaasl ike MOCVD-proqram behoort so spoe-

d1g moontlik aangepak te word, aangesien

die veld baie vinnig u i t b r e i .

OR J i a w Auaust 1983

Germany, UK, Denmark l Republic of China

PURPOSE Of VISIT

• To visi t laboratories involved in research programmes of interest to the NIMR.

• To attend the I UP AC Commission 11.3 as the South African representative.

• To visit the Republic of China as a member of a South African delegation. (Separate report.)

CONCLUSIONS AM) SUGGESTIONS

• The laboratory visits established new contacts and renewed old contacts. Valuable advice was obtained on X-ray crystallography, single crystal growth, fast-ion transport materials and microstructural studies in hard materials.

• The f i rs t contract bursary, offered to Or M Zabel, was accepted. The new scheme is obviously an attractive incentive to research workers to visit South Africa.

• At the IUPAC Commission 11.3 meeting useful contacts were established and a proposal to hold the Fourth International Conference on High Temperature Materials was accepted provisionally. A final decision wil l be taken at the third meeting in Santa Fe, USA in April 1984.

OR J B CLARK ?0 March - 13 April 1984

USA

PURPOSE OF VISIT

• To attend the Fourth International Conference on High Temperature and Energy Related Materials and to present a paper.

OR J i a N K

Augustus 1983 Ouitsland, VK, Deneaarke I Republiek van China

DOEL VAN BESOEK

- 0» laboratoria wat geaoeid is met navor-sinqsprogramme wat vir die NIMN van belang i s , te besoefc.

• 0* 'IUPAC' Kommissie 11.3 as Suid-Afrikaanse verteenwoordiger by te woon.

• 0» die Republiek van China as l id van "n Suid-Afrikaanse afvaardiging te besoek. (Afsonderlike verslag.)


• Die laboratoriuMbesoeke het tot nuwe kon-takte gelei en vorige kontakte verstewig. waardevoile advies is ingewin ten opsigte van x-straalkristallografie, enkelkristal-groei en mikrostrukturele ondersoeke van harde materiale.

• Die eerste kontrakbeurs wat aan dr M Zabel gebied is , is aanvaar. Die nuwe skema is duidelik 'n aantreklike aansporing aan na-vorsers om Suid-Afrika te besoek.

• By die 'IUPAC' Kommissie I I . 3 vergaderinq is nuttige kontakte gemaak en 'n voorstel om die Vierde Internasionale Konferensie oor Hoétemperatuurmateriaal te hou is voor-lopiq aanvaar. 'n Finale besluit sal by die derde verqaderinq in Santa Fe, VSA in April 1984 geneem word.

DR J B CLARK 20 Maart - 13 April 1984

VSA

DOEL VAN BESOEK

» Om die Vierde Internasfonale Konferensie oor Hoetemperatuur- en Energieverwante Ma-terfaal by te woon en 'n referaat te lewer.

127

• To attend the Meeting of the IUPAC COMMIS

SION II.3.

• To visit Manpower training centres for the

polyaer research programme of tht NIHR.

• To visit Materials research organizations.

CONCLUSION! AND SUGGESTIONS

• The Fourth International Conference on High

Temperature and Energy Related Materials

was Most stimulating and excellent examples

of outstanding research were presented. The

sixth conference in this series is to be

held, with IUPAC sponsorship, in South

Africa in November 1989.

• NIHR polymer research candidates have se

lected high quality training centres. The

visits enabled assessment of the various

organizations to be made.

• Prominent materials researchers who might

be invited to work at the NIMR were identi

fied.

OR J H DAL TON

September 1983

Israel

PURPOSE OF VISIT

• To make contact with fellow researchers

in heat-resistant alloys and to become

familiar with research programmes in this

f ie ld in Israel.

• To visit industries and research establish

ments involved with heat-resistant alloys

and to see at f i rst hand the techniques and

equipment and fac i l i t ies reoufred.

• To discuss the philosophy and planned modus

operandi of the NIMR heat-resistant alloy

programme and to use the experience gained

• OM die vergadering van 'IUPAC' KoMMissie

I I . 3 by te woon.

• OM Mannekragopleidinqsentra vir die pol : -

meernavorsinqsproqr am van die NIMN te be-

soek.

• OM Materiaalnavorsing-orqanisasies te be-

soek.

GEVOLGTREKKINGS EN AAMEVELlNGS

• Oie Vierde Internasionale Konferensie oor

Hoetemperatuur- en Energieverwante Mate-

r iaal was uiters stimulerend en uitstekende

voorbeelde van hooqstaande navorsing is

aangebied. Oie sesde konferensie in hier-

die reeks sal in November 1989 in Suid-

Afrika gehou word en deur MP AC geborg

word.

• NlMN-kandidate vir potimeernavorsing net

opleidingsentra van gehalte gekies. Oie

besoeke het beoordeling van die onderskeie

organisasies toegelaat.

• Vooraanstaande materiaalnavorsers wat

moontlik genooi kan word om by die NIMN te

werk, is qeïtíentifiseer.

OR J H 0M.TOR

September 1983

Israel

OOEL VAN BES0EK

v

• Om kontak te maak met mede-navorsers op die

gebied van hittebestande legerings en on

bekend te raak met navorsingsproqramme op

hierdie gebied in Israel.

• Om nywerhede en navorsingsentra wat met

hittebestande legerinqs gemoeid is , te be-

soek en eerstehands die nodige teqnieke,

toerustinq en fas i l l te i te te beslgtiq.

• Om die f i losofie en beplande modus operandi

vir die hittebestande legeringsprogram van

die NIMN te bespreek en om die ondervindfnq

128

during the visi t to formulate ideas on fur

ther research into heat-resistant alloys.

• To explore possible areas of cooperation

and/or assistance.


• Contact was made with the important re

search organizations and research pro

grammes on both sides were discussed exten

sively. Visits were also made to the major

industries involved in the production of

components from heat-resistant alloys.

• I t was generally f e l t that the NIMR pro

gramme was ambitious and that a large in

jection of funds and staff would be requir

ed to produce meaningful results. However,

i t would appear that the general philosophy

and direction found approval. I t was, how

ever, fe l t that the area of chemical anal

ysis, and in particular trace element anal

ysis, should be addressed before any super-

alloy research proqramme could prove suc

cessful. Research areas currently being

addressed covered ceramic mould research,

vacuum melting and casting, including uni

directional sol idif ication, foundry re

search, thermal fatigue and creep studies,

crack propagation studies, etching techni

ques, and coatings and surface treatments.

• The main comments to sprirg from the indus

tr ia l visits are

•• the hiqh level of quality control prac

tised at each staqe of the manufacture

of superalloy components

•• the hiqh technological level of the

fac i l i t ies and equipment required

•• the number and the quality of the

scientific and technical staff

It was felt that many worthwhile contacts

had been made and that these should be

wat qedurende die besoek opqedoen word te

gebruik em idees vir verdere navorsing op

hittebestande leqerinqs te forauleer.

• Om moontlike qebiede van samewerking en/of

ondersteuninq te ondersoek.


• Kontak is net belangrike navorsingsorqani-

sasies gemaafc en navorsingsprogramme is var

beide kante breedvoerig bespreek. Besoeke

is ook afgelê by die belangrikste nywerhede

wat by die produksie van komponente uit

hittebestande legerings betrokke is .

• Daar is oor die alqemeen gevoel dat die

NIMN-proqram ambisieus is en dat 'n groot

inset van fondse en personeel nodiq sal

wees am betekenisvolle result ate te lewer.

Dit wil egter voorkom asof die algemene

f i losofie en die rigting van die ondersoeke

goedkeurinq wegdra. Daar is egter ook ge

voel dat die gebied van chemiese analise,

en in die besonder, spoorelement-analise,

aangepak behoort te word voordat enige

superlegeringnavorsingsprogram suksesvol

sal wees. Navorsingsgebiede wat tans aan-

daq geniet, is keramiekgietvorm-navorsing,

vakuumsmeltinq on -qieting, insluitende

enkelrigtingstolling, gieterynavorsing,

termiese vermoeidheid en kruipondersoeke,

kraakvoortplantingstudies, etstegnieke, en

bedekkinq- en oppervlakbehandelinys.

• Die belanqrikste kommentaar wat uit die

nywerheidsbesoeke voortspruit, is

•• die hoë vlak van kwaliteitbeheer wat by

elke stap tydens die vervaardiginq van

superlegerinqskomponente toegepas word

•• die hoe tegnologiese vlak van die fas i -

l i t e i te en toerusting wat nodiq is

•• die aantal en kwaliteit van die weten-

skapUke en teqniese personeel

• Die gevoel is dat verskeie kontakte wat die

moeite werd is, gemaak is en in stand qehou

i?q

maintained and expanded so that possible areas of collaboration may be explored.

• The organizations visited included:

•• The Department of Materials Engineering, Technion, Haifa

•• The Israel Institute of Metals, Technion, Haifa

•• The Department of Materials Engineering, Ben Gurion University of the Negev, Beer Shera

•• Israel Aircraft Industries Ltd., Engineering Division

•• Israel Aircraft Industries Ltd, Bedek Aviation Division

•• Carmel Forge Ltd., Haifa

•• Iscar Blades Ltd., Nahariya

•• Turbochrome Ltd., Yahud.

OR J T FOURIE Auqust 1983

USA and Canada

PURPOSE OF VISIT

• To attend the Seventh International Conference on High Voltage E)ectron Microscopy at the University of California, Berkeley, USA.

• To visit laboratories concerned with studies in plastic deformation and the application of electron microscopy to such studies.


• Papers presented at the High Voltaqe Electron Microscopy Conference emphasized the fact that increased penetration in high voltage is of secondary importance to the higher resolution achieved by working at

en uitgebrei behoort te word sodat noont-like saaewerkingsgebiede ondersoek kan word.

• Die organisasies wat besoek is sluit in:

*• Departeawnt Materiaalingenieurswese, Technion, Haifa

•• Israel Instituut van Mecale, Technion, Haifa

•• Departewent Materiaalingenieurswese, Ben Gurion Universiteit van die Negev, Beer Shera

•• Israel Aircraft Industries Ltd., Ingenieursafdeling

•• Israel Aircraft Industries Ltd., Bedek Lugvaartafdeling

•• Carmel Forge Ltd, Haifa

•• Iscar Blades Ltd., Nahariya

•• Turbochrome Ltd, Yahud

OR J T FOURIE Augustus 1983 VSA en Kanada

OOEL VAN BESOEK

• Om die Sewende Internasionale Konferensie oor Hoogspanningelektronmikroskopie by die Universiteit van Kalifornie, Berkeley, VSA by te woon

• Om laboratoriums te besoek wat betrokke is by studies van plastiese vervormlng en die toepassing van elektronmikroskopie op sulke studies.


• Leslngs gelewer by die Konferensie oor Hooqspann1nge1ektronmikroskopie net die feit benadruk dat toename fn indringing met gebrulk van hoogspanning van sekondire be-lang is vergeleke by die hoë'r oplosvermoé'

130

higher voltages. I t became clear that the

new «edium hign voltage (300 - 400 kV) con-

mere i ally prodjeed electron microscopes

were beinq employed increasingly in atomic

resolution studies or alternatively in

advanced analytical applications.

• Research by metal physicists at the General

Motors Research Laboratories on the manner

in which mild steel sheets are gripped

mechanically before being stamped into body

parts have led to a new procedure. This

has allowed the use of a sizeably smaller

edge portion, which is trimmed off later as

scrap. The savings brought about by this

improvement wi l l run into millions of dol

lars annually. This example once more

il lustrates the tremendous impact that

materials research could have in an indus

t r i a l environment.

OR S HART

July - August 1983

USA and UK

PURPOSE OF VISIT

• To present two papers at the biennial

AIRAPT Conference on High Pressure Physics.

• To visit a number of laboratories special

izing in a range of materials development

programmes.


• High pressure studies at the NIMR are com

parable with the other well established

laboratories workinq in the same area. How

ever, the NIMR should develop the newer

systems like the miniature diamond anvil

cell and be prepared to use a wider variety

of analytical tools coupled to high press

ure. A major impression of the Conference

was the variety of powerful tools being

brouqht to bear to exploit the unique fea

ture of ultra high pressure, i .e. the

wat verfcry word deur by hoér spannings te

werk. Oit net duidelik qeword dat die kom-

mersieel-geproduseerde nuwe êdiumhoogspan-

rungelektronmikroskope (300 - 400 kV) in

toenemende mate in atoomresolusiestudies of

anders in qevorderde i i a l i t i ese toepassings

qebruik word.

• Navorsing wat deur metaalfisici by General

Motors se navorsinqslaboratoriums onderne-.m

is oor die wyse waarop sagte staalplate me-

ganie: geklem word voordat dit as bakwerk-

onderdele uitgedruk word, net tot 'n ruwe

prosedure gelei . Dit het d • gebruik van

"n aanmerklik kleiner randqederlte wat

later as skroot afgesry word, moontlik ge-

maak. As gevolg van hierdie verbetering,

sal mi'joene dollars jaarl iks bespaar

word. Hierdie voorbeeld i l lustreer weer-

eens die qeweldige invloed wat mater1'aal-

.lavorsing op die nywerheidsomgewing kan he.

OR SHORT

Julie - Agustus 1983

VSA en VK

D0EL VAN BES0EK

• 0m twee referate te lewer by die twee-

jaarlikse AIRAPT Konferensie oor Hoêdruk-

f isika

• 0m 'n aantal laboratoria te besoek wat in

materiaal-ontwikkelingsprogramme spesiali-

seer.

GEVOLGTREKKINGS EN AANBEVELlNGS

• Hoëdrukstudies by die N1MN vergelyk goed

met die van ander goed gevestigde laborato

r ia wat op dieselfde qebied werksaam is.

Die NIMM behoort egter die nuwer sisteme

soos byvoorbeeld die miniatuur diamantsel

te ontwikkel en moet ook bereid wees om 'n

breër verskeidenheid anali*.fese teqnieke

wat met hoé' druk verband hou, aan te wend.

Die verskeidenheid kragtfge teqnieke wat

gebruik word om die toepassing v<m ultra-

hoe druk te benut, soos die veranderinq in

131

:h*r,ge in latt ice parameter and the appli

cation of \uch techniques to Materials af

today such is semiconductcs and ceramics.

It is noteworthy that some of the pioneer

ing groups are being incorporated into

Materials Departments in their institutes.

• A variecy of groups specializing in Materi

als development in crystals and ceramics

«ere visited. Present work at the NIMt is

well focussed and we should continue to de

vote attention to areas where we are com

petent and relevant and avoid trying to

deal with too «any problems with our l imi t

ed manpower. The need for a more extensive

effort in single crystal growing at the

NIMR is apparent.

OR H G C HUPM

September 1982 - August 1983

Italy and The Netherlands

PURPOSE OF VISIT

• To undertake research on the use of lasers

as excitation sources in the f ie ld of atom

ic fluorescence in cooperation with a

scientist of international standing.

• To attend and present three papers at the

Colloquium Spectroscopic!» Internationale

XXIII in Amsterdam, The Netherlands.


• Research results showed laser excited fluo

rescence to be a powerful technique both

for ana'ytical determinations and for diag

nostic work with plasmas. The technology

of wavelength tunable pulsed dye lasers has

advanced to the stage where sufficient

energy is available to saturate the excited

atomic energy levels, resultfnq in qood

stabi l i ty and sensitivity. When used to

obtain diaqnostic values in plasmas, the

great advantage of fluorescence measure

ments with laser excitation is the qond

spatial resolution of this technique

die roosterparameter en die toepassing van

sulke tegnieke op hedendaaqse materiale

soos halfgeleiers en keramieke net besonder

beindruk tydens die konferensie. Oit is

opmerksaam dat soamige van die pioniers-

groepe in die Nateriaaldepartemente van hgl

onderskeie institute geïnkorporeer word.

• Verskeie groepe wat in die ontwikkeling van

k r is ta l - en keramiekmateriaal spesialiseer,

is besoefc. Huidige werk by die NINN is

tans ooed qerig en ons behoort voort te

gaan om aandag te skenfc aan gebiede waar

ons oor kundigheid beskik en wat ter sake

i s , en «net daarteen waak om te veel pro

blem* met ons beperkte mannekraq te probeer

aanpak. Die behoefte aan "n groter poging

in enkelkristalqroei-teqnieke by die NIMH

blyk duidelik.

OR H G C t tMM

September 1982 - Augustus 1983

I t a l i e en Nederland

OOEL VAN BESOEK

• Om saam met 'n internasionaal-bekende

wetenskaplike op die qebied van atoomfluo-

ressensie navorsinq te doen oor die gebruik

van lasers as opwekkingsbron.

• Om die Cc'loquium Spectroscopic!** Interna

tionale XXIII te Amsterdam, Nederland by te

woon en drie referate daar te lewer.

GEVOLGTREKKINGS EN AANBEVFLINGS

• Navorsingsresultate het getoon dat laser-

opqewekte fluoressensie 'n kragtige tegniek

is vir sowel analitiese bepalings as diag-

nostfese werk met plasmas. Die tegnologie

van golflengte-lnstelbare gepulsde kleur-

stoflasers het so ve»- gevorder dat qenoeg

enerqie tydens die puis beskikbaar is om

die opqewekte atoomenerqievlakke te versa-

dig, met goeie stabi l i te i t en sensitiwiteit

tot qevo'q. By gebruik vir diaqnostiese

metings in plasmas is die qroot voordeel

van fluoressensie-metinqs met laseropwek-

kinq dat goeie ruimtelike oplossinq met

132

(~1 mm3). I t is essential that the Atomic

Spectroscopy group have a laser system at

thei r disposal to carry out fur ther re

search on analy t ica l ly useful plasmas such

as the ICP and the low pressure gas d is

charge.

• The papers read at the CSI in Amsterdam

showed that there has been l i t t l e fundamen

ta l development in the f i e l d of analyt ical

atomic spectroscopy. Exist inq techniques

have been further developed, applied and

studied. The focus of interest is on the

application of inductively coupled plasma

emission and graphite furnace atomic ab

sorption techniques.

OR D S JONES

May 1984

UK

PURPOSE OF VISIT

• To perform acceptance tests on tt.e ZAB high

resolution mass spectrometer before ship

ment to the CSIR

• To attend a f ive day t ra in inq course en the

ZAB mass spectrometer

• To v i s i t laboratories with mass spectrome

t ry equipment similar to that 01 the NIMR.

CONC'.USIONS AND SUGGESTIONS

• The high resolution ZAB mass spectrometer

due for delivery in July 1984 w i i l great ly

f a c i l i t a t e the analysis of metal samples.

Tests were performed on NBS mild steel

standarcs and preliminary results indicate

that the mass spectrometer is capable of

y ielding hlqh accuracy results on a routine

basis. Analyses can be performed much

faster than on the present low voltage d is

charge mass spectrograph. The added advan

tage of a high resolution capabi l i ty ena

bles the user, with the aid of the data

system, to measure mass peaks accurately in

hierdie tegnieke verkry word (~1 mm ). Dit

is noodsaaklik dat die Atoomspektroskopie-

groep ' r lasersisteem tot hul beskikking

het om navorsingswtrk oor ana l i t i es -b ru ik -

bare plasmas soos die IGP en die laedruk-

gas-ontlading voort te s i t .

• Die voordragte by die CSI te Amsterdjin het

getoon dat daar weinig fundamentele ontwik-

kelings op die gebied van anal i t iese atoom-

spektroskopie was. Bestaande tegnieke is

verder uitgebou, toegepas er, ondersoek. Die

meeste belangstel l inq heers in die toepas-

sing van die induktief-gekoppelde plasma-

emissie- en grafietoond-atoomabsorpsie-

teqnieke.

OR 0 S JONES

Mei 1984

VK

OOEL VAN BESOEK

• Om aanvaardingstoetse op die ZAB-hoêresolu-

sie-massaspektrometer u i t te voer voor ver-

skepinq na die HNNR

• Om 'n vyfdaagse kursus oor die ZAB-spektro-

meter by te woon

• Om laborator ia met massaspektrometrie-

toe r -Mnq soortqelyk aan die' van die NIMN

te besoek.


• Die ZAB-hoe'resolusie-massaspektromeU.-, met

aflewerinqsdatum Jul ie 1984, sal die on t le -

ding van metaalmonsters groot l iks vergemak-

l i k . Toetse is met monsters van saqte NBS-

staalstandaarde uitqevoer en voorlopiqe re

sul tate dui aan dat die massaspektrometer

op 'n roetine-basis baie akkurate resul tate

kan verskaf. Ontledinqs sal baie vinniqer

uitqevoer kan word as wat die geval is met

die huidige laespanninoontladinq-massaspek-

trograaf. Die verdere voordeel van goeie

rt solusievermoé' stel die qebruiker in staat

r • pieke in die massaspektrum met behulp

133

the spectrum and unambiguously Identify the isotope under investigation.

• The five day training course was well organized and covered, in detail, aspects of instrument maintenance, operation and software cor,t>ol. There was adequate opportunity to discuss specific problems with experts in the field concerned,

• The software, written in PASCAL, is not yet perfect for our own applications, as the majority of users of these spectrometers are involved only in organic analysis. To reduce total analysis time it is suggested that we modify certain parts of the software to suit our own requirements. The modifications will require, however, the purchase of a PASCAL compiler.

OR A I KINGON July 1983

USA

PURPOSE OF VISIT

• To present a paper at the 1983 Gordon Conference on Solid State Studies in Ceramics

• To visit four laboratories in the USA.

CONCLUSIONS ANO SUGGESTIONS

• This Gordon Conference was particularly relevant because of discussions on new developments in powder processing of ceramics. A number of leading scientists from outside the field of ceramics gave presentations relevant to the manipulation and characterization of powder particles in suspension.

> The other extremely interesting aspect of the conference was the conclusion reached that a number of areas of solid state sintering remain poorly understood, despite

van die datastelsel akkuraat te meet en om die isotoop wat ondersoek word, duidelik te identifiseer.

• Die vyfdaagse opleidinqskursus was goed ge-orqaniseer en het aspekte van programma-tuurbeheer en van instrument-funksionering en -onderhoud in besonderhede gedek. Daar was genoegsame geleentheid om spesifieke problems met deskundiges op die betrokke gebied te bespreek.

• Die programmatuu"-, geskryf in PASCAL, is nog nie heeltemal gepas vir toepassings hier nie, aangesien die meerderheid gebrui-kers van hierdie spektrometers slegs by or-ganiese ontleding betrokke is. Daar word voorqestel dat gedeeltes van die programma-tuur deur ons gewysiq word om by ons ver-eistes aan te pas ten einde totale ontle-dingstyd te verminder. 'n PASCAL-vertaler sal eqter hiervoor aangekoop moet word.

OR A 1 KINGON Julie 1983

VSA

DOEL VAN BESOEK

• Om 'n voordraq te lewer by die 1983 Gordon Konferensie oor Vastetoestand-ondersoeke op Keramieke

• Om vier laboratoria in die VSA te besoek.


• Hierdie Gordon Konferensie was besonder toepaslik aanqesien nuwe ontwikkelinge in die poeierprosessering van keramieke bespreek 1s. 'n Aantal leidende wetenskap-11kes bulte die qebied van keramieke het voordragte gelewer wat verband hou met die manipulasie en karakterisering van poeier-partikels in suspensie.

• 'n Besondere Interessante aspek van die konferensie was die gevolgtrekkinq wat ge-maak is dat nieteenstaande die feit dat se-kere sintermodelle reeds vir jare aanvaar

134

the fact that certain sintering models have been accepted for years. These areas include particle coarsening, grain boundary mobility, pore mobility and their respective and combined contributions to overall densif'cation kinetics.

• Visits were made to Rutqers University and the Ceramics Group at the National Bureau of Standards, which is well known for its work on the mechanical characterization of ceramics. In particular, discussions were held on the test methods for particle impact erosion of ceramics. This is particularly relevant in South Africa because of the increasing use of engineering ceramics in pneumatic conveying.

• Visits were aiso paid to the Department of Materials Engineering, North Carolina State University, and the Materials Research Laboratory, Pennsylv/nia State University. The Symposium 'Plastic Deformation of Ceramic Materials' was attended at Pennsylvania State University.

OR A I KINGON

September 1983

Japan

PURPOSE OF VISIT

• In conjunction with a t r i p to Taiwan, (separate report) a v i s i t was made to Japan to establish contact with a number of sc ient is ts in the f i e l d of special ceramics.


• Progress in the f i e l d of advanced or spec ia l ceramics is extremely rapid in Japan, with electronic ceramics in par t icu lar being commercialized at an astonishinq rate.

• The research and development investment in

special ceramics is large, with companies

word, 'n aantal terreine van die vastetoe-

stand-sinterinq noq steeds nie qoed ver-

staan word n i e , onder andere par t ike lkor -

re lg roe i , kor re lgrens-mobi l i te i t , por ie-

mob i l i t e i t en hul onderskeie en gekombi-

neerde bydrae to t die verd igt ingsk inet ika.

• Die Rutgers Univers i te i t is besoek, asook die Keramiekgroep by die Nasionale Buro v i r Standaarde, wat goed bekend is v i r werk op die meganiese karakter iser ing van kera-mieke. In besonder is samesprekings qehou oor die toetsmetodes v i r par t ike lbots ing-erosie van keramieke. Hierdie aspek is van besondere toepassing op Suid-Afrika as ge-volg van die toenemende qebruik van inge-nieurskeramieke in druklugaangedrewe ver-voer.

• Besoek is ook gebring aan die Departement Materiaalinqenieurswese van die Noord Carolina Staatsun ivers i te i t , en die Mate-riaalnavorsingslaboratorium van die Pennsylvania Staatsun ivers i te i t . Die sim-posium 'P las t ic Deformation of Ceramic Materials ' is by Pennsylvania Staatsunivers i t e i t bygewoon.

OR A I KINGON September 1983

Japan

DOEL VAN BESOEK

• Tesame met 'n besoek aan Taiwan (afsonder-like varslaq), is Japan besoek om kennis te maak met 'n aantal wetenskaplikes op die gebied van spesiale keramieke.


• Vorderinq op die qebied van qevorderde of spesiale keramieke vind in Japan teen 'n ufters vinniqe tempo plaas. Veral elektroniese keramieke word verbasend vinnig gekommersiall seer.

• Die beleqqinq in navorsinq en ontwlkkelinq ten opslqte van spesiale keramieke is

135

investinq relatively hiqh properties of

turnover (typically 6t) in reseach and

development. For example, Toshiba has

1 500 people doinq research and development

at one research centre, and a significant

number of these are workinq on electronic

ceramics.

Technical highlights of the visit were:

•• The development of PbTi03-based piezo

electric ceramics by Toshiba. These

ceramics display large 33-mode coupling

and no 31-mode ."•uplinq. These materi

als are *.. «refore worth investiqating as

hydrostatic transducers.

•• Measurement of residual stress of piezo

electric ceramics by a modified indenta

tion technique by Prof. K Okazaki at the

National Defence Academy.

•• The extent to which the enqineerinq per

formance of the new structural ceramics

is being investigated at places such as

the Asahi Reseach and Development

Centre.

•• Work on interface effects on sintering

being done at the National Institute for

Research in Inorganic Materials (NIRIM)

by Dr Y Inomata.

•• The preparation of diamond coatinqs by

plasma assisted chemical vapour deposi

tion, also at NIRIM.

•• The development of a new sialon material

by NGK Spark Pluq which can be fabricat

ed by air sintering and which has ex

tremely qood mechanical properties.

Visits were also made to Matsushita Re

search Laboratories, Osaka University and

Tokyo Institute of Technoloqy.

A lecture was given at the Tokyo Institute

of Technoloqy,

groot. Maatskappye belê relatief 'n groot

deel van hulle omset (tot 6X) in navorsinq

en ontwikkeling. Toshiba, byvoorbeeld, het

1 500 mense by een navorsingsentrum in

diens. 'n Aansienlike aantal van hierdie

mense werk op die gebied van elektroniese

keramieke.

• Tegniese hoogtepunte van die besoek was:

•• Die ontwikkeling van PbTi03-qebaseerde

piësoëlektriese keramieke deur Toshiba.

Hierdie keramieke toon sterk 33-koppel-

modes maar qeen 31-koppel-modes nie.

Dit sou dus die moeite werd wees om

hierdie materiaal as moontlike hidrosta-

tiese oordraers te ondersoek.

•• Die bepalinq van oorblywende spanning in

piësoëlektriese keramieke deur middel

van 'n gewysigde inkepinqsteqniek van

prof. K Ozaki van die Nasionale Verde-

diginqsakademie.

•• Die aandaq wat by plekke soos die Asaki

navorsinqsentrum bestee word aan onder-

soeke van die inqenieurs-werkverngtinq

van nuwe strukturele keramieke.

•• Werk deur dr Y Inomata van die 'National

Institute for Research in Inorqanic

Materials' (NIRIM) met betrekkinq tot die

skeidingsvlakeffekte tydens sintering.

•• Die voorbereidinq van diamant-bedekkinqs

deur middel van plasma-geassisteerde

chemiese dampneerslag. Hierdie werk

word ook by NIRIM qedoen.

•• Die ontwikkelinq deur NGK Spark Pluq,

vart 'n nuwe sialon-materiaal wat deur middel van luqsintering vervaardig word

en wat uitstekende meqaniese eienskappe

het.

• Besoeke is ook gebring aan die Matsushita

Navorsinqslaboratoriums, Osaka Universiteit

en die Tokyo Instituut vir Teqnologie.

• 'n Lesinq is by die Tokyo Instituut vir

Tegnoloqie qelewer.

136

MR S 0 OLSEN June - July 1983

The Netherlands, France, Switzerland, Germany and Norway

PURPOSE OF VISIT

• To attend and present papers at the Colloquium Spectroscopicum Internationale XXIII and 10th International Conference on Atomic Spectroscopy in Amsterdam

• To visit research, materials development and analytical service laboratories in France, Switzerland, Germany and Norway.


• Further understanding of the fundamental processes in spectroscopic sources such as the inductively coupled plasma, necessitates the use of dye lasers. Development and further refinement of atomic spectroscopic techniques will depend strongly on the availability of such fundamental knowledge. Disappointingly few groups are involved in research of this nature.

• Several research groups have modified ICP torches for operation at lower enerqies and qas flow rates with no apparent loss in powers of detection. Although more economical to use, it can be expected that these torches will result in more pronounced matrix effects due to poorer atomizat ion efficiency.

• By far the largest body of work in ICP atomic emission spectroscopy deals with application and development of methodology for the analysis of bioloqical, orqano-metallic, geochemical and metallurgical materials.

• Of the laboratories visited, the Applied Analytical Chemistry Section, 'Commissariat a 1'Energie Atomlque (CEA), Paris bears most resemblance to the Materials Characterization Division here. Generally, 90S

M R S D OLSEN Junie - Julie 1983

Nederland, Frankryk, Switserland, Ouitsland en Noorwee

DOEL VAN BESOEK

• Om die Colloquium Spectroscopicum Internationale XXIII en die lOde Internasionale Konferensie oor Atoomspektroskopie te Amsterdam by te woon en referate daar te lewer

• Om navorsinq-, materiaalontwikkeling- en analitiese dienslaboratoria in Frankryk, Switserland, Ouitsland en Noorweë te be-soek.


• Verdere begrip van die fundamentele proses-se in spektroskopiese bronne soos die in-duktief-gekoppelde plasma, vereis die ge-bruik van kleurstoflasers. Ontwikkeling en voortgesette verfyning van atoomspektrosko-piese tegnieke sal baie afhang van die be-skikbaarheid van sulke fundamentele kennis. Dit is teleurstellend dat min groepe by na-vorsing van hierdie aard betrokke is .

• Verskeie navorsingsgroepe het IGP-fakkels gewysig om by laer energieë en gasvloei-snelhede te funksioneer sonder skynbare verlies aan bepalingsvermoë. Hoewel meer ekonomies om te qebruik, kan verwag word dat matriks-effekte met hierdie buise meer benadruk sal wonf weens swakker atomise-ringsdoeltreffendheid.

• Verreweg die grootste hoeveelheid werk in IGP-atoomemissie-spektroskopie handel oor die toepassing en ontwikkeling van die me-todoloqle vir die ontledinq van bioloqiese, organo-metaliese, geochemiese en metallur-glese materlale.

• Van die laboratoria wat besoek is, stem dif Afdeling Toegepaste Analitiese Chemie, 'Commissariat a l'Énergie Atomique' (CEA), Parys die meeste ooreen met die Afdeling Materiaalkarakterlserlnq hler. Oor die a l -

137

of their work is for the different depart

ments of the CEA and 101 for outside orga

nizations. Some of th£ staff are dedicated

to applied chemical investigations and

basic research. In addition to sections

concerned wit'-' atomic spectroscopy, X-ray

fluorescence, gas analysis, surface analy

sis (Auger and ESCA), mass spectrometry and

electronic support, they also have separate

sections for wet chemistry, analytical

application of lasers (eight lasers and two

dye lasers), and electro-chemical analysis.

• Established relationships exist between the

NIMR and other laboratories visited such as

Laboratoire Suisse de Recherches Horlogéges

(LSRH), Neuchatel; Centre Nationale de la

Recherche Scientifique (CNRS), Lyon, and

Institut fur Spectrochemie und Angewandte

Spektroskopie (ISAS), Dortmund. Continued

cooperation with the Institut Nîonal des

Sciences Appliqueés, Lyon, should be of

great benefit to the NIMR as this laborato

ry deals with the fabrication and behaviour

of materials (metals, semiconductors etc.)

from a wide interdisciplinary framework.

DR P U RICHTER

July 1983

Europe

PURPOSE OF VISIT

• To establish contact with the Houldsworth

School of Applied Science at Leeds Univer

si ty , UK.

• To attend Zirconia - 83, Stuttgart, West

Germany.

• To attend the Twelth International Confer

ence on the Science of Ceramics, Saint-

Vincent, I ta ly .


« The Houldsworth School of Applied Sciences

at the Leeds University fs very well equip-

geween word 901 van hul werk onderneen vir

verskillende interne departemente en 101

vir organisasies van buite. Somnige van

die personeel is slegs gemoeid met onder-

soeke op die gebied van toegepaste chemie

en basiese navorsinq. Afgesien van seksies

betrokke by atoomspektroskopie, X-straal-

fluoressensie, gas-ontleding, oppervlak-

ontleîtig (Auger en ESCA), massaspektro-

metrie en elektroniese ondersteuning, is

daar ook afsonderlike sekstes vir nat

chemie, analitiese toepassinq van lasers

(agt lasers en twee kleurstof lasers), en

elektrochemiese analise.

• Gevestigde betrekkinqe bestaan tussen die

NIMN en rider laboratory urns wat besoek is ,

soos Labo.-atoire Suisse de Recherches

Horlogéges (LSRH), Neuchatel; Centre

Nationale de la Recherche Scientifique

(CNRS), Lyon, en Institut fiir Spectrochemie

und Angewandte Spektroskopie (ISAS),

Dortmund. Voortgesette samewerking met die

Institut National des Sciences Appliq.iee's,

Lyon, behoort van groot waarde vW die NIWN

te wees aangesien hierdie laboratorium ge

moeid is met die vervaardiging en gedrag

van materiale (metale, halfgeleiers ens.)

uit 'n wye interdissiplinêre vakgebied.

DR P U RICHTER

Julie 1983

Europa

DOEL VAN 8ES0EK

• Om kontak te maak met die Houldsworth

Skool vir Toegepaste Wetenskappe, Leeds

Universiteit, Enqeland.

• Om die Zirconia - 83 Konferensie te

Stuttqart, Wes-Duitsland by te woon.

• Om die Twaalfde Internasionale Konferensie

oor Keramiekwetenskap te Saint-Vincent,

Italié' by te woon.


• Die Houldsworth Skool van Toegepaste weten-

skappe te Leeds Universiteit is baie goed

138

ped for ceramic studies. The very promising

preparation technique for silicon ni t r ide,

post-sintered reaction bonded silicon n i

tride (PSR8SN), was discussed.

• The Zirconia - 83 conference indicated that

the theoretical basis for various asoects

of Zr0 2 processinq had been laid down. The

processing and structural applications were

clearly tied to commercial considerations

as was apparent when considering the dis

plays of various engine parts, applications

in the steel industry, etc. However, the

need for caution against oversell, as had

been the case with silicon ni tr ide, was

expressed. The physical and non-structural

applications progressed well , but did not

differ drastically from those of a previous

conference.

• The Science of Ceramics Conference indicat

ed that silicon nitr ide and zirconia ceram

ics are very promising structural materials

for use in car enqines. Intense activity

is centred around research concerning these

aspects. Techniques of pressureless sin

tering, and the nitrogen demand method in

the processing of s i l icr nitride are being

investigated in an attempt to move away

from the use of hot-isostatic pressing or

hot-pressing.

• Bioceramics for use as implants in the

human body need to be developed, in partic

ular for the improvement of the mechanical

strenqth of the so-called bio-active glass-

ceramics. Dense high purity alumina as a

bio-inert material has withstood the test

of time.

OR I SI6AIAS

October 1983

Europe

PURPOSE OF VISIT

• To work it the High Pressure Physics labo

ratory of the University of Umea, Sweden.

toegerus vir ondersoeke van keramieke. Die

besondere belowende bereidingstegniek vir

si l ikonnitr ied, naaalik na-gesinterde reak-

siegebonde-silikonnitried is bespreek.

• Uit die konferensie Zirkonia - 83 het oe-

blyk dat die teoretiese basis van verskeie

aspekte van die prosessering van Zr0 2 reeds

gevestig is . Die prosessering en struktu-

rele toepassinqs is duidelik verbonde aan

koamersiële oogmerke soos blyk uit die u i t -

stallings van verskillende motor-onderdele,

toepassinqs in die staalnywerheid, ens.

Daar is egter qemaan om nie soos in die ge-

val van sil ikonnitried, oor-optimisties te

wees nie. Die fisiese en nie-strukturele

toepassings het goed ontwikkel maar het se-

dert die voriqe konferensie nie dramatiese

veranderinge getoon nie.

• Die Konferensie oor die Keramiekweïínskap

het laat blyk dat sil ikonnitried- en sirko-

nia keramieke baie belowende strukturele

materiale is vir gebruike in motorenjins.

Uitgebreide aktiwiteite heers ten opsigte

van navorsing wat hierdie aspekte onder-

soek. Tegnieke soos druklose sinter en 'n

stikstof-opnamemetode in die prosessering

van silikonnitried word ondersoek in 'n po-

qinq om weg te beweeq van warm-isostatiese

persinq en warmpersinq.

• Biokeramieke, wat vir inplanterinq in die

menslike liqgaam gebruik word, benodig ver-

dere ontwikkelingswerk, veral ten opsigte

van 6\e verbeterinq tan die meqaniese

sterkte van die sogenaamde bio-aktiewe

qlaskeramieke. Diqte hoe'-suiwerheid alumina

is nog steeds 'n voorloper as bio-inerte

materiaal.

DR 1 SIGALAS

Oktober 1983

Europa

DOEL VAN BESOEK

• Om in die Hoe'drukf isika Laboratorium aan

die Universiteit van Umea, Swede te werk.

139

• To visit the University of Manchester, UK.


• The Physics Department of the University of

Umea houses the group which is presently

foremost in the world as far as measurement

of thermal conductivity at high pressures

is concerned. A similar activity has been

started at the NIMR which thus made this

visit very desirable. More importantly,

collaboration has started between the NIMR

group and several other groups around the

world, the aim of which is the standardiza

tion of methods used in these studies.

• The thermal conductivity of NaBr up to

pressures of 2 GPa and in the temperature

range from 100 to 400 K was experimentally

determined durinq this v is i t . The same ex

perimental set-up was used to measure the

thermal expansion coefficient as a function

of pressure. The results were analysed in

terms of the Leibfried-Schlomann formula.

I t was found that most of the heat in NaBr

is conducted by means of the acoustic pho-

nons, while the ">Dtic phonons contribute

very l i t t l e at the high end of the tempera

ture range investigated.

• At Umea important interaction was possible

with two of the foremost scientists in the

f ield of thermal conductivity, namely Dr R

Ross and Or G Slack. The method developed

at the CSIR was discussed extensively and

compared with others. The foundation of

very good collaboration was laid and it is

hoped tha' both these scientists will be

visiting Pretoria in the near future.

• The latest developments in the f ie ld of

mainetism as well as the possibility for

future collaboration were discussed at the

University of Manchester.

• Om Manchester Universiteit in Engeland te

besoek.

GEVOLGTREKKINGS EN AANBEVELtNGS

• Die Departement Fisika van die Universiteit

van Umea huisves tans die wereId se mees

vooraanstaande qroep wat die meting van

termiese qeleidingsvermoë onder hoê drukke

betref. 'n Soortqelyke aktiwiteit wat on-

langs by die NIMN tot stand gebring is . hct

hierdie besoek dus qewens gemaak. Wat egter

van groter belang is , is dat met samewer-

king tussen die NIMN-groep en verskeie

ander internasionale groepe begin is met

die doel om die metodes wat in hierdie

ondersoeke gebruik word te standaardiseer.

• Tydens hierdie besoek is die termiese ge-

leidingsvermoê' van NaBr tot drukke van

2 GPa oor die temperatuur-gebied van 100

tot 400 K eksperimenteel bepaal. Dieselfde

eksperimentele opstelling is gebruik om die

termiese uitsettingskoe'ffisient as funksie

van druk te meet. Resultate is in terme

van die Leibfried-Schlomann-formule geana-

liseer. Daar is bevind dat die meeste van

die warmte-geleidinq in NaBr deur middel

van akoestiese fonone plaasvind ter-yyl die

optiese fonone baie min bydra by die hoë

temperature wat ondersoek is.

• By Umea was belangrike interaksie moontlik

met twee van die wêreld se mees vooraan

staande wetenskaplikes op die gebied van

termiese geleidingsvermoé' naamlik dr R Ross

en dr G Slack. Die metode wat by die WNNR

ontwikkel is , is deeglik bespreek en met

ander tegnieke verqelyk. 'n Basis vir goeie

samewerking is gelê en albei hierdie weten

skaplikes sal Pretoria hopelik in die nabye

toekoms besoek.

• Die nuutste ontwikkelings op die oebied van

magnetisme, sowel as die moontlikheid vir

toekomstiqe samewerkinq is by Manchester

Universiteit bespreek.

140

OR C P) STAMEN

Apr i l 1984

UK and Gertany

n C H STANDCR

Apr i l 1984

VK en Duitsland

PURPOSE Of VISIT OOEL VAN BESOEK

To attend the European Conference on Sur

face Science 1984 (EC0SS84), held at the

University of York, UK, in order to consult

with leading surface sc ient is ts regarding

the most suitable character izat i >i techn i

ques for use in materials development pro

grammes.

On d ie '984 Konferensie oor Oppervlakweten-

skap (EC0SS84) by die Univers i te i t van

York, VK, by t e «toon ten einde Met vooraan-

staande oppervlakwetenskaplikes te raad-

pleeg in verband met die mees qeskikte

oppervlakkarakteriseringstegnieke v i r mate-

riaalontMikkelinqsprogra

To v i s i t manufacturers of surface charac

te r iza t ion equipment in the UK and Germany

in order to decide on the s u i t a b i l i t y of

equipment.

On vervaardiqers van toerust ing v i " opper-

vlakkarakter iserinq in beide die VK en

Ouitsland te besoek ten einde oor dip

geskiktheid van apparaat te bes lu i t .

To v i s i t the University of Regensburg to

plan future cooperat ve research.

On d ie U i i v e r s i t e i t van Regensburg te be

soek on toekomstiqe qesamentlike navorsing

te beplan.

CONCLUSIONS AND SUGGESTIONS ÊEVOLGTREKKINGS EN AANBEVELINGS

Attendance at ESC0SS84 was of major benefi t in

that i t allowed for discussions with leading

sc ient is ts on the fol lowing top ics :

Bywoning van ESC0SS84 was van groot waarde

aanqesien besprekings van die volgende onder-

werpe met vooraanstaande oppervlakwetenskap-

l ikes gevoer kc- word:

Techniques givinq the most relevant data

for surface analysis.

Teqnieke wet die mees totpasl ike data v i r

oppervlakanalise verskaf.

Configuration for these techniques i .e . the

couplinq of a l l techniques to one vacuum

system vs separate single technique ins t ru

ments.

Konfigurasie van hierdie teqnieke, naamlik

die koppelinq van a l le tegnieke aan een

vakuumsisteem vs afsonderlike enkelteqniek-

instrumente.

The most suitable instrumental configura

t ion for high resolution electron energy

loss spectroscopy (HREELS).

Die mees qeskikte instrumentele konf igura

sie vir gebruik met hoê-resolusie elektron-

enerqieverlies-spektroskopie (HREELS).

• The u t i l i z a t i o n of Aiger spectra to gain

more insight into the electronic properties

of materials.

The discussions led to the fol lowing answers

to the above questions:

• Die benuttinq van Auoer-spektra om 'n beter

ins ig in die elektroniese struktuur van

materiaal te verkry.

Die besprekinqs net gelei tot die volqende

antwoorde op boqenoemde vrae:

141

• X-ray photoelectron spectroscopy, secondary

ion mass spectroscopy. Auger-electron spec

troscopy (AES) and ion scattering spectros

copy are the most useful techniques when

mounted on one vacuum system.

• HREELS requires a very good vacuum (better

than 5,10~ 1 0 mbar) and is best combined

with low energy electron diffraction and

AES on one vacuum system.

• Auger spectra may be used for obtaining

density of states and spin-orbit couplinq

information.

Equipment manufactured by VG Instruments Ltd . ,

Kratos Instruments, Physical Electronics and

Leybold-Heraeus GmbH were studied in detail

and it was decided that the LHS-10 system made

by Leybold-Heraeus would be best for our pur

pose.

Durinq discussions at the University of

Regensburg with Prof. K -J Range i t was decid

ed to extend the work done on electron density

in AgTe3 to AgTe2 and AgTe.

MR P J TERBLAHCHé

April - May 1984

USA

PURPOSE OF VISIT

• To attend a short course on ceramic powder

processing presented by the National

Institute of Ceramic Engineers (NICE)

• To attend the American Ceramic Society

Annual Conference

• To learn more about the manufacture of

piezoelectric ceramics in a production

environment.


• The emphasis of the NICE course was on con

ventional powder processing. The inter-

• X-straalfotoelektronspektroskopie, sekon-

dêre ioon-massaspektroskopie, Auger-elek-

tronspektroskopie (AES) en ioonverstro-.-

ing-spektroskopie is die nuttigste teanieke

as hulle aan "n enkele vakuumsisteem gekop-

pel word.

• HREELS vereis 'n baie goeie vakuun (beter

as 5 ,10" 1 0 mbar) en kombinasie met lae-

energie-elektrondi*~fraksie en AES aan een

vakuum-sisteem is aangewese.

• Auger-spektra kan vir die beoaling van in-

ligtinq oor toestandsdiqtheid en spinbaan-

koppeling gebruik word.

Apparaat gebou deur VG Instruments Ltd. ,

Kratos Instruments, Physical Electronics en

Leybold-Heraeus GmbH is deeglik bestudeer en

daar is besluit dat die LHS-10 sisteem, van

Leybold-Heraeus, die beste vir ons doeleindes

sal wees.

Tydens besprekings met Prof. K -J Range van

Regensburg Universiteit is besluit om die na-

vorsing op elektrondigtheid in AgTes uit te

brei na AgTe2 en AgTe.

MR t J TERBL/WCHé

April - Hei 1984

VSA

DOEL VAN BESOEK

• Om 'n kort kursus oor keramiekpoeierproses-

sering by te woon wat deur die Nasionale

Instituut van Keramiekingenieurs (NICE)

aangebied is

• Om die Amerikaanse Keramiekvereniging se

jaarlikse konferensie by te woon

• Om meer te leer omtrent die vervaardfqing

van piësoéïektriese keramieke in 'n produk-

sie-omgewinq.


• By <iSe NICE-kurses het die klero op konven-

sionele poeierprosessering geval. Die ver-

142

re la t ion of processing steps with proper

t ies was emphasized. Discussions on spray

ing, calcination and powder dispersion were

par t icu la r ly relevant to present NIHR work.

So l -ge l , spray-roasting and freeze-drying

methods were also discussed.

wantskap tussen die prosesserinqstappe en

eienskappe is beklemtoon. Sesprekings oor

sproeidroqinq, ve rh i t t i ng en poeier disper-

gering hou besondere verband met huidige

werk by die NIMH. So l -ge l , sproeidroging

en vriesdroqinq bereidinqsmetodes is ook

hespreek.

The unprecedented growth and world-wide

interest in ceramics was ref lected by the

wide variety of exhibi ts and the large num

ber of papers and posters presented at the

American Ceramic Society Conference. The

importance of ce. awic materials in i>»dern

technoloqy is stressed further by the large

number of sc ient is ts and engineers commit

ted to major research programmes in ceramic

science. The chemical synthesis of high

pur i ty ceramic powders with control led

physical properties is of much interest at

present, and is pa r t i cu la r l y relevant to

NIMR research.

Die onqekende groei en 'n wêreldwye belang-

s t e l l i n g in keramieke is weerspieël in die

groot verskeidenheid u i t s t a l l i n g s en die

groot aantal referate en plakkaatsessies

tydens die konferenste van d ie Amerikaanse

Keramiekverenginq. Die belanqrikheid van

keramiekmateriale in die moderne teqnologie

is verder beklemtoon deur die groot aantal

wetenskaplikes en ingenieurs wat betrokke

is by belanqrike navorsingsprogramme in die

keramiekwetenskap. Die chemiese sintese

van keramiekpoeiers met hoë suiwerheid wat

oor beheerrie f i s iese eienskappe beskik, wek

tans groot belanqstel l ing en is besonder

toepaslik op navorsinq by d ie NIMN.

Anwnq other topics of interest were piezo

e lec t r i c composites, new hydrophone mater i

a l s , dispersion techniques, s in te r ing , wear

mechanisms and conventional processing ope

rat ions.

Ander onderwerpe van belang het piësoéïek-

t r iese samestell ings, nuwe hidrofoonmateri-

a le , dispergeringstegnieke, s in te r ing , s l y -

tasiemeoanismes en konvensionele prosesse-

ringstappe inqes lu i t .

Useful information on the large scale pro

duction of PZT was obtained from commercial

companies. The major observation was the

use of purpose-made equipment for bulk

handling of hiqh pur i ty materials on a lonq

term basis. The very close relat ionship

between properties and the chemistry-iMcro-

structure of piezoelectr ic ceramics r e

quires u l t ra consistent mater ials.

Waardevolle i n l i q t i n q oor die grootskaalse

produksie van PZT is van handelsmaatskappye

verkry. Die gebruik van spesiale toerus-

t ing v i r die qrootskaalse hanterinq van

hoë-suiwerheíd materiale oor 'n langer t yd -

perk was besonder opvallend. Die baie nou

verwantskap tussen materiaaleienskappe en

chemise mikrostruktuur van piësoëlektr iese

keramieke, vereis materiaal wat u i ters kon-

sekwent reaqeer.

OR M M THACKERAY

Apr i l 1984

Europe

OR N M THACKERAY

Apri l 1984

Europa

PURPOSE OF VISIT DOEL VAN BESOEK

To present a paper at the Second Interna

t ional Meetinq on Lithium Batteries in

Paris.

On 'n referaat te lewer by die Tweede

Internasionale Byeenkoms oor Ut iumbatterye

te Parys.

14?

• To visi t staff of the Inorganic Chemistry

Laboratory, Oxford University and Ruther

ford Appleton Laboratory to discuss recent

results of collaborative programmes on

solid-solution-electrodes for lithium bat

teries.

• To inspect the high integrity dry box fac i

l i t y required by the NIMR at V N Barrett

Ltd. , Croydon, Surrey.


• A joint paper from the NIMR/Oxford Univer

sity entitled 'Characteristics of LiMn20„

Cathode in Lithium Cells' was presented at

the 2nd International Meeting on Lithium

Batteries in France. Latest developments

in lithium batteries were discussed and re

viewed at the Conference. I t is clear that

lithium batteries are « t i l l in their in

fancy, and at present constitute a very

small percentage of the world market of low

drain, ambient temperature battery systems.

Greater technological advances in lithium

batteries are s t i l l required before this

market can be effectively penetrated.

• Considerable time was spent at Oxford Uni

versity f inalizing joint patent and publi

cation specifications. Fruitful discus

sions were held regarding recent electro

chemical and structural data of transition

metal oxide electrodes that are currently

under investigation at che NIMR. A colla

borative programme with the Rutherford

Appleton Laboratory has also been in pro

gress for the past eighteen months. In

particular, structural analyses of numerous

l i thiated and delithiated transition metal

oxide systems are beinq undertaken by

neutron diffraction techniques. Data for

these analyses are beinq collected by staff

of the Rutherford Laboratory at the Inst i

tute Laue Langevin, Grenoble, France.

Recent results obtained at the NIMR and in

the UK were discussed.

• Om personeel by die Anoroaniese Chemie

Laboratorium, Oxford Un*versiteit en die

Rutherford Appleton Laboratarium te besoek

ten einde onlangse resultate wat verkry is

in gesamentlike programme oor vastetoe-

stand-elektrodes vir litiumbatterye te be-

spreek.

• On by V M Barrett Bpk, Croydon, Surrey, on-

dersoek in te stel na die hoë-integriteit

droê' handskoenkas-fasiliteit wat deur die

NIMN benodiq word.


• 'n Gesamentlike referaat van die NIMN en

Oxford Universiteit getiteld: 'Character

istics of LiMn20<, Cathode in Lithium Cells'

is by die 2de Internasionale Byeenkoms oor

Litiumbatterye in frani.ryk voorpedra. Die

nuutste ontwikkelings in litiumbatterye is

by die konferensie bespreek en dit net dui-

delik geblyk dat litiumbatterye nog in 'n

vroeë ontwikkelingstadium is en tans slegs

'n geringe deel van die wêreldmark van lae-

stroom kamertemperatuur batterysisteme

vorm. Hierdie mark kan alleenlik doeltref-

fend binneqedrinq word indien qroter tegno-

logiese deurbrake op litiumbatterye gemaak

word.

• Heel wat tyd is by Oxford Universiteit deur-

gebring om 'n gesamentlike patent en publi-

kasiespesifikasies te finaliseer. NufMqe

besprekint,s oor onlangse elektrochemiese en

strukturele data van oorgangsmetaaloksied-

elektrodes wat tans by die NIM'i ondersoek

word, is gehou. 'n Samesprekingsproqram met

die Rutherford Appleton Laboratorium is ook

die afqelope agtien maanóe in werking. In

besonder is strukturele analises met neu-

trondiffraksie-teqnieke onderneem van 'n

qroot aantal oorgangsmetaaloksiedsisteme

waartoe litium bygevoeg en weer onttrek is.

Data vir hierdie analises word deur die

personeel van die Rutherford Laboratorium

by die Instituut Laue Langevin, Grenoble,

Frankryk inqewin. Onlangse resultate wat

by die NIMN en in Engeland verkry is, is

ook bespreek.

MR J T TH1RLUN.L

Nay 1984

USA and UK

MM J T THIRLMN.L Nei 1984 VSA en VK

PURPOSE OF VISIT

• To attend courses in energy-dispersion X-

ray analysis and image analysis at compa

nies from which equipment has recently been

purchased.

• To v i s i t research ins t i tu tes active in the f i e l d of l i gh t element microprobe analysis in order to evaluate the f i r s t quant i ta t ive analyses of th is type carr ied out on the JEOL 733 microprobe analyser.


• The techniques of both energy dispersion X-ray (EDX) analysis and on- l ine analysis of electron-beam images have underqone rapid development over the last decade and, through the capabi l i t ies of present-day min'-computers, have become readi ly ava i l able as tools in the research laboratory.

However, companies which design these systems are usually computer-based and the t ra in ing programs which they of fer may emphasize that aspect of the techno1o9y to the detriment of other Important areas. In part icular the l imi tat ions imposed on the resul ts by the qual i ty of the or ig ina l physical data were usually ignored and an opt imist ic view of the precision and accuracy of the results was presented.

• The analysis of materials containing l i gh t elements (boron, carbon, n i t rogen, oxyqen and f l u o r i n e ) , using an electron microprobe, has always been recognized as a d i f f i c u l t task. This >s due in part to the problems of measuring low enerqv X-ray wavelengths and intensi t ies and also to the l imi ta t ions of correcting the measured in tens i t ies for the ef fects of the severe photon absorption which occurs in most sam-

OOEL VAN RESOEK

• Om kursusse in energie-dispersiewe X-

straalanal ise en beeldanalise by te woon by

maatskappye van wie toerust ing onlangs ge-

koop i s .

• Om navorsingsinrigt inqs wat op d ie gebied van ligte-element mikrosorde-analise werk-saam i s , te besoek ten cinde die eerste kwantitatiewe analises van h ierd ie aard wat op die JEOL 733-mikrosonde-analiseerder uitgevoer i s , te evalueer.

GEVOuGTREKKINGS EN AANBEVELINGS

• Die energiedispersiewe X-straal (EOX)-ont-ledingstegniek sowel as die tegniek van intydse ontleding van elektronbundelbeelde het die afgelope dekade vinni i ; ontwikkel en as gevolg van die huidige vermoëns van minirekenaars geredelik in die navorsinqs-laboratorium as hulpmiddels beskikbaar qe-word.

• Maatskappye wat hierdie s te lse ls ontwerp is egter gewoonlik rekenaafQeriq en die op le i -dingsprogramme wat hi , l ie aanbied map dus h ierd ie as?ek van die tegnologie benadruk to t nadeel van ander belangrike aspefcte. In die besonder is die beperkings op die re -su l t a te , as gevolg van die kwa l i te i t van die oorspronklike f i s iese data, gewoonlik geTgnoreer en is 'n opt imist iese siening van die nou n-igheid en akkuraatheid van die result ate aangebied.

• Die mikrosonde-analise van materiale wat l i q t e elemente (boor, koolstof , s t i k s t o f , suurstof en f l uo r ) bevat, is nog al tyd as 'o moeil ike taak beskou. 01t is qedeelte-l i k te wyte aan die probleme verbonde aan die meting van lae-energie X-s t raa lgo l f -lenqtes en - In tens i te i te asook aan die beperkings van die vereiste v i r reqste l l lnq van gemete in tens i te i te v i r d ie effekte van die groot mate van fotonabsorpsie wat in

145

pies. Many laboratories have taken a quali tat ive approach by simply comparing samples with very similar standards. The few laboratories carrying out quantitative ca l culations have progressed «el l during the last few years in the analysis of oxides. However, further work is required in connection with more precise measurement of absorbtion coefficients for the characteristic radiation from the other elements in this region of atomic weights.

SOOTH AFRICAN MATERIALS SCIENCE A » ENGINEERING DELEGATION

September 1983 Republic of China

NIMR Members J B CLARK, A P BENTLEY, H BOOYENS

N R CONINS, J H DALTON, J T FOUR IE, A I KINGON

PURPOSE OF VISIT

• A South African delegation o* materials specialists visited the Republic of China from 30 August to 9 September 1983. The delegation consisted of representatives from the CSIR, the Universities of Pretoria and Port Elizabeth, Vereeniging Refractories, and the Industrial Development Corporation. Middelbu'q Steel and Alloys was represented by C5IR staff.

• The delegation took part in the f i rs t CSIR (ROSA)* - NSC (ROC) Metal Alloys, Ceramica and Si lane Workshops. In addition a number of visits were paid to universities, research institutions and industries.

• The prime aim was to establish contacts and identify areas where joint research programmes could be established in the future.

* The Republic of South Africa is referred to as ROSA and the Republic of China as ROC to nutch Chinese practise, concernina the ROSA-ROC Exchange Agreement.

die meeste sonsters vocHo». Baie labora-toria het 'n kwalitatiewc benadering waar-deur monsters eenvoudiq met standaarde wat sterk ooreenstem, verqelyk word. Die klein aantal laboratory a wat kwantitatiewe bere-keninqs onderneem, het «tie afqelope paar jaar qoeie vorderinq met die analise van oksiede gemaak. In verb and met die meer presiese meting itn absorpsiekoeffisiëhte vir die karakteristieke stralinq van die ander elemente in hierdie omoewing van atoomgewigte, is verdere werfc egter nodig.

SUID-NFRIUIMBC INTERIMLHETERSKAP EH -IKCRIEUR9ESE AFVAMBIGINS

September 1983 Republiek van China

NIMN-lede J B CLARK, A P BENTLEY, H BOOYENS,

N R COHINS, J H DALTON, J T FOURIE, A I KINGON

OOEL VAN BESOEK

• 'n Suid-Afrikaanse afvaardiging van mate-riaaldeskundiges het die Republiek van China van 30 Augustus tot 9 September 1983 besoek. Die afvaardiging het bestaan uit verteenwoordigers van die WNNR, die Univer-si tei te van Pretoria en Port Elizabeth, 'Vereeniging Refractories', en die Nywer-heidsontwikkelinqskorporasie. 'Middelburq Steel and Alloys' is deur WNNR personeei verteenwoordig.

• Die afvaardiqing het deelgeneem aan die eerste 'CSIR (ROSA)* - NSC (ROC) Metal Alloys, Ceramics and Si lane Workshops'. Verder is 'n aantal besoeke aan universi-te i te , navorsinqsorganisasies en nywerhede gebring.

• Die belangrikste oogmerk was om kontak te bewerkstelliq en moontllke areas te identi-fiseer vir die vestigirrq van Coekomstige qesamentlike navorsingsprogramme.

• Oaar word na die Republiek van Suid-Afrika as ROSA verwys en na die Republiek van China as ROC in ooreenstemninq met Chinese gebrulk ten opsigte van die ROSA-ROC Uitruilooreenkoms.

146

CONCLUSIONS AND SUGGESTIONS GEVOLGTREKKINGS EN AANBEVELINGS

• As part of the Workshop, a document was drawn up entitled 'Recommendations of the first CSIR (ROSA) - NSC (ROC) Metal Alloys, Ceramics and Silane Workshops'.

• Following a detailed discussion of this document by Dr C W Wang - Vice President of the NSC, Dr Choh Li - NSC, Mr Nelson Hsiunq - NSC, Dr G Heymann - Deputy-President of the CSIR and leader of the South African delegation, and Or J 8 Clark - CSIR, the following points were agreed to:

•• Drs Li and Clark were nominated to promote all future dealings regarding materials research contact between ROSA and ROC.

•• The priorities established and listed in IMAT 43 were accepted. Only three items were accepted for further development at present. These include

- development of new types of corrosion resistant steels

- heat resistant alloys - HgCdTe and GaAs-electronfc materials.

•• The electronic materials area will be developed at a workshop to be held in approximately six months' time 1n ROSA. Or Li will lead a delegation of five people.

•• The programmes on new corrosion resistant steels and heat resistant alloys should be referred back to Interested parties to draw up detailed programmes and to work out funding implications for the next three years.

The action should include the following

- research workers to define projects

• As deel van die Werksessie is 'n dokument met die titel 'Recommendation of the first CSIR (ROSA) - NSC (ROC) Metal Alloys, Ceramic and Silane Workshops' gepubliseer.

* Na 'n breedvoeriqe bespreking van hierdie dokument deur dr C W Wang - Vise-President van die NSC, Dr Choh Li - NSC, mnr Nelson Hsiung - NSC, dr G Heymann - Adjunk-Direk-teur van die WNNR en leier van die Suid-Afrikaanse afvaardiging, en dr J B Clark -WNNR, is op die volgende ooreengekom:

*• Drr Li en Clark is genomineer om alle toekomstige onderhandelinge ten opsigte van materiaalnavorsingskakeling tussen ROSA en ROC te bevorder.

•• Prioriteite, soos bepaal en in rangorde geplaas in IMAT 43, is aanvaar. Slegs drie items is tans vir verdere ontwikke-linq aanvaar. Dit sluit in

- ontwikkeling van nuwe tipes korrosie-bestande stale

- hittebestande iegerings - HgCdTe en GaAs-elektroniese mate-

riale.

•• Die area vir elektromese materlale sal uitgebou word tydens 'n werksessie wat oor ongeveer ses maande in ROSA gehou sal word. Dr L1 sal 'n afvaardiging van ongeveer *yf persone lei.

•• Die programme oor nuwe korrosiebestande stale en hittebestande legerings sal na bolanghebbende partye terugverwys word om programme in besonderhede op te stel en om finansleringsimplikasles v1r die volgende drie jaar u1t te werk.

Bedrywlghede behoort die volgende in te sluit

- navorsers deflnleer die projekte

- exchange of project proposals (man

years not actual costs to be budgeted)

- agreement on projects

- to be submitted to NSC and CSIR for independent funding.

• I t is the recommendation of the delegation that this course of action be pur.jed but that attention be paiu to technology transfer and joint patentinq programmes to ensure a healthy relationship. Furthermore, to undertake research work rather tl.an just an exchange of researchers, a new source of funds will be required. The NSC confirmed that the funds required from ROC vould be available immediately.

- uitrui l van projekvoorstelle (manjare moet beqroot word, nie werklike koste nie)

- ooreenstemming oor projekte

- voorlegging aan NSC en WNNR vir onaf-hanklike finansierinq.

• Die afvaardiqinq beveel aan dat hierdie rigting ingeslaan word maar dat aandag ge-skenk moet word aan die oordrag van tegno-logie en gesamentlike patent-programme om 'n gesonde verhouding te versefter. Om navorsing te onderneem eerder as slegs wetenskaplikes uit te r u i l , sal *n nuwe bron van inkomste nodig wees. Die NSC het bevestig dat die nodige fondse van ROC on-middellik beskikbaar sal wees.

148

M E M B E R S H I P O F I N T E R N A T I O N A L C O M M I T T E E S L I O M A A T S K A P V A N I N T E R N A S I 0 N A L E K O M I T E E S

1. J B CLARK International Advisory Committee member for the 9th International Conference of the

International Association for Advancement of Hiqh Pressure Science and Technology, USA Internasionale Advieskomiteelid vir die 9de Internasionale Konferensie van die

Internasionale Verenging vir die Bevorderinq van Hoëdrukwetenskap en -tegnologie, VSA

2. J B CLARK National representative on IUPAC Commission I I .3 - Commission on High Temperature and

Solid State Chemistry Nasionale verteenwoordiger op IUPAC Kommissie I I . 3 - Kommissie oor

Hoëtemperatuur- en Vastetoestand-chemie

3. J B CLARK

National representative on the International Advisory Committee of the International Materials Congress

Nasionale verteenwoordiger op die Internationale Advieskomitee van die Internasionale Materiaalkongres

4. A HELLS South African representative on International Federation for Heat Treatment of Materials

Suid-Afrikaanse verteenwoordir • by die Internasionale Federasie v i r die H i t tebc mJeling van Materiale

M E M B E R S H I P O F N A T I O N A L C O M M I T T E E S L I D M A A T S K A P V A N N A S I O N A L E K O M I T E E S

1. J 8 CLARK Co-opted member of the South African IUPAP National Committee

Gekoopteerde l i d van die Suid-Afrikaanse IUPAP Nasionale Komitee

2. J B CLARK Member of the Executive Committee of the South Afr ican Powder Metallurgy Association

Lid van die Uitvoerende Komitee van die Suid-Afrikaanse Poeiermetallurgiese Vereniginq

3. J B CLARK

Member of the National Materials Programme Ceramics Feedstocks Steering oomnittee Lid van die Nasionale Materiaalprogram Keramiekvoerstowwe Loodskomitee

4. J B CLARK Member of the National Materials Programme Section Committee for Ceramics and Related Materials

Lid van die Nasionale Materiaalproqram Seksiekomitee v i r Keramieke en Verwante Materiale

5. J B CLARK Member of the National Materials Programme Section Committee for Metals and Alloys

Lid van die Nasionale Materiaalproqram Seksiekomitee v i r Metale en Leqerings

6. J B CLARK Member of the Research and Development Coordination Committee for Microelectronics

Lid van die Navorslng- en 0ntwikkel1ngskom1tee v i r Mikro-elektronika

149

7. J B CLARK Member of the Council of the South African Institute of Physics

Lid van die Raad van die Suid-Afrikaanse Instituut vir Fisika

p. J B CLARK Member of the Advisory Board of the Department of Metallurgy and Materials Science,

University of Cape Town Lid van die Advieskomitee van die Departement Metallurgie en Materiaalwetenskap,

Universiteit van Kaapstad

9. J B CLARK Member of the Advisory Board of the Nuclear Physics Institute, University of the Witwatersrand Lid van die Advieskomitee van die Instituut vir Kernfisika, Universiteit van die Witwatersrand

10. J B CLARK Member of the Advisory Committee for the National Physical Research Laboratory, CSIR

Lid van die Advieskomitee van die Nasionale Fisiese Navorsingslaboratorium, WNNR

11. J B CLARK Member of the Advisory Committee for the National Chemical Research Laboratory, CSIR

Lid van die Advieskomitee van die Nasionale Chemiese Navorsingslaboratorium, WNNR

12. J B CLARK Member of the Advisory Board for the Carl and Emily Fuchs Institute for Microelectronics

at the University of Pretoria Lid van die Adviesraad vir die Carl en Emily Fuchs Instituut vir Mikro-elektronika

aan die Universiteit van Pretoria

13. N R COMINS Member of the National Materials Programme Metallic Glass Steering Committee

Lid van die Nasionale Materiaalprogram Metaalglas Loodskomitee

14. N R COMINS Member of the Executive Committee, Electron Microscopy Society of Southern Africa

Lid van die Uitvoerende Komitee van die Elektronmikroskopiese Vereniging van Suidelike Afrika

15. N R COMINS Member of the Executive Committee, Solid State Physics and Materials Science Specialist Group

of the South African Institute of Physics Lid van die Uitvoerende Komitee van die Vastetoestand-Fisika en Materiaalwetenskap

Spesialisgroep van die Suid-Afrikaanse Instituut vir Fisika

16. N R COMINS Membe> of the Committee for High Voltage Electron Microscopy/High Resolution Electron Microscopy of tr.e Electron Microscopy Society of Southern Africa and the South African Institue of Physics Lid van die Komitee vir Hoëspanninqselektronmikroskopie/Hoëskeidfnqselektronmikroskopie van die Elektronmikroskopievereniging van Suidelike Afrika en die Suid-Afrikaanse Instituut vir Fisika

17. N P FERREIRA Member of South African Committee for Certified Reference Materials

Lid van die Suid-Afrikaanse Komitee v1r Gesertifiseerde Verwysingsmateriaa'

150

18. H FIDOS

Member of the Council of the South African Institute of Foundrymen

Lid van die Raad van die Suid-Afrikaanse Instituut vir Gieterymanne

19. J T FOURIE

Member of the Executive Committee of the Electron Microscopy Society of Southern Africa

Lid van die Uitvoerende Komi tee van die Elektronmikroskopievereniginq van Suidelike Afrika

20. J T FOURIE

Member of the Executive Committee of the Solid State Physics and Materials Science Specialist Group of the South African Institute of Physics

Lid van die Uitvoerende Komi tee van die Vastetoestand-Fisika en Materiaalwetenskap Spesialisgroep van die Suid-Afrikaanse Instituut vir Fisika

2 1 . J T FOURIE

Member of the Committee for High Voltage Electron Microscopy/Hioh Resolution Electron Microscopy of the Electron Microscopy Society of Southern Africa and the South African Institute of Physics

Lid van die Komitee vir Hoêspanningselektronmikroskopie/Hoëskeidingselektronmikroskopie van die Elektronmikroskopievereniging van Suidelike Afrika en die Suid-Afrikaanse Instituut vir Fisika

22. A R HARDING

Committee Member of the Institution of Metallurgists (South African Region)

Koniteelid van die Vereniging van Metallurge (Suid-Afrikaanse streek)

2 3 . A I KINGON

Member of the Council of the South African Ceramic Society

Lid van die Raad van die Suid-Afrikaanse Keramiekvereniging

2 4 . A I KINGON

Chairman of the South African Powder Metallurgy Association

Voorsitter van die Suid-Afrikaanse Poeiermetallurgie Vereniging

25. J PIERRUS

Secretary/Treasurer of the Solid State Physics and Materials Science Specialist Group of the South African Institute of Physics

Sekretaris/Tesourier van die Vastetoestand-Fisika en Materiaalwetenskap Spesfalisqroep van die Suid-Afrikaanse Instituut vir Fisika

26. V SENTARLI

Member of the Council of the South African Institute of Foundrymen

Lid van die Raad van die Suid-Afrikaanse Instituut vir Gieterymanne

27. V SENTARLI

CSIR Representative on SABS Bentonite Committee

WNNR Verteenwoordiqer op SABS Bentoniet-komitee

28. A WELLS

Committee Member of the Specialist Heat Treatment Committee of the South African Institute of Foundrymen

Komiteelid van die Spesialis Htttebehandelfnq Komitee van die Suid-Afrikaanse 'nstituut vir Gieterymanne

151

N I N R C O L L O Q U I A N I H N C O L L O Q U I A

OR G BRANDT Sandvik, A.B., Sweden CERAMIC CUTTING TOOLS

8 May/Mei 1984

PROF. M COHEN Department of Materials Science and Engineering, MIT, Cambridge, Massachusetts, USA

A PERSPECTIVE ON MATERIALS SCIENCE ANO ENGINEERING 17 Oct/Okt 1983


THE NATURE OF MARTENSITIC TRANSFORMATIONS 19 Oct/Okt 1983

PROF. M COHEN

Department of Materials Science and Engineering, MIT, Cambridge, Massachusetts, USA THEORY OF NUCLEATION IN MARTENSITIC TRANSFORMATIONS

20 Oct/Okt 1983


PHYSICAL METALLURGY OF RAPIDLY SOLIDIFIED ALLOYS 1 Nov 1983

PROF. J D COMINS Department of Physics, University of the Witwatersrand, Johannesburg

STUDIES OF DEFECTS IN CRYSTALS USING OPTICAL TECHNIQUES 26 Oct/Okt 1983

PROF. D ELWELL Crystal Science Division, Centre for Materials Research, Stanford University, California, USA

SOLAR SILICON 25 Nov 1983

DR B J FITZPATRICK Philips Laboratories, 8riarcliff Manor, New York

CRYSTAL GROWTH OF TtTRAHEDRALLY COORDINATED MATERIALS 23 Nov 1983

PROF. E GU.'MANAS Department of Materials Engineering, Technion - Israel Institute of Technology, Haifa, Israel

COLD SINTERING OF POWDERS UNDER HIGH PRESSURE 16 Sep 1983

OR R HUTCHINGS Department of Metallurgy and Materials Science, Universi ty of Cape Town, Cape Town/Kaapstad

AN ASSESSMENT OF NITROGEN-ION IMPLANTATION AS A SURFACE TREATMENT FOR WEAR RESISTANCE 19 Jun 1984

U . OR N M JAMES

Department of Metal lurgy and Mater ia ls Science, Un ivers i ty of Car t r idge, England

FATIGUE CRACK CLOSURE - ITS OCCURRENCE, MEASUREMENT AND RELEVANCE TO CRACK GROWTH

3 Apr 1984

12. OR L M LEVINSON General Electric Company, Corporate Research and Development, Schenectady, N.Y.

ELECTRONICS CERAMICS, ESPECIALLY ZnO VARISTORS FOR PROTECTION AGAINST VOLTAGE SURGES 9 Aug 1983

13. PROF. F R N NABARRO Department of Physics, University of the Witwatersrand, Johannesburg

CONFIGURATION». FORCES AND MECHANICAL FORCES IN THE INTERACTION BETWEEN LATTICE DEFECTS 17 Aug 1983

14. PROF. A RABENAU Max Planck Institute for Solid State Research, Stutto"-*, West Germany

LITHIUM NITRIDE AND RELATED MATERIALS - CASE STUDY OF THE USE OF MODERN SOLID STATE RESEARCH TECHNIQUES - A REVIEW

4 Sep 1983

15. PROF. H RAWSON Department of Ceramics, Glass and Polymers, University of Sheffield, England

RECENT DEVELOPMENTS IN GLASS SCIENCE 1 May/Mei 1984

16. DR M P SHAW Metals Division, NIMR, CSIR, Pretoria

APPLICATIONS OF CONVERGENT BEAM ELECTRON DIFFRACTION IN MICROSTRUCTURAL STUDIES 6 Mar 1984

17. PROF. R SWANEPOEL Department of Physics, Rand Afrikaans University, Johannesburg

AMORPHOUS SILICON 31 Aug 19P"

18. PROF. B-7 WEISS Department of Materials Engineering, Technion - Israel Institute of Technology, Haifa, Israel

STRUCTURE OF HIGH VACUUM, HIGH TEMPERATURE BNi-5 BRAZED JOINT OF INCONEL 718 15 Sep 1983

19. DR P L WESSEl ? National Chemical Research laboratory, CSIR, Pretoria

HIGH RESOLUTION NMR SPECTROSCOPY OF SOLIOS 5 Jun 1901

20. OR M ZABEL Universi ty of Reoensburq, West Germany

STRUCTURAL AND CHEMICAL RELATIONS IN METAL-RICH TERNARY CHALCOGENIDES WITH SHANDITE AND PARKERITE-STRUCTURE

2\ Feb 1984

153

V I S I T I II 6 S C I E N T I S T S A N D S T U D E N T S B E S O E K E N D E M E T E N S K A f> I I K E S E N S T U D E N T S

MRHHO CARR Industr ia l Training Student f ro» Surrey Univers i ty , UK

Sep 1983 - Feb 1984

PROF. 0 ELUELL

Materials Research Laboratory, Stanford Univers i ty , USA

Nov 1983

OR B J FITZPATRICK

Phi l ips Laboratories, New York, USA Nov 1983

PROF. D GERLICH Department of Physics and Astronomy, Tel Aviv University, Israel

Feb - Aug 1983

MR G HARDING Industr ial Training Student from Brunei Univers i ty , Uxbridge, England

Apr - Sep 1984

MR P FERREIRA

Universi ty of Natal , Durban

Dec/Des 1083 - Feb 1984

PROF. H RAWSON

Materials Consultant, Sheffield, UK Apr 1984

MR J N SPEED Industrial Training Student from Brunei University, Uxbridge, Enqland

Apr - Sep 1983

MR A P STEVENS Industrial Training Student from Bath University, England

Feb - Aug 1984

PROF. B-Z WEISS Head, Department of Materia's Engineering, Technion - Israel Institute of Technology,

Technion City, Haifa, Israel Jun - Aug 1983

OR M ZABEL Department of Chemistry, University of Regensburg, West Germany

Oct/Okt 1983 - Sep 1984

f

ï t

V I S I T O R S F R O M A B R O A D I U I T E I A I D S E I E S O E K E R S

1. PROF. M ARCAN

Department of Applied Mechanics, Technion, Israel

Jun 1984

2. MRS/ME V. L ARCAN

Department of Applied Mechanics, Technion, Israel

June/Junie 1984

3. OR B BARTOCHA

Division of International Programs, National Science Foundation, Washington DC, USA

Mar 1984

4. MR/MNR R BOBBER

Private Consultant, USA

Jan 1984

5. MR/MNR G BRANDT

Sandvik AB, Sweden

May/Mei 1984

6. PROF. CHUN YEN CHANG

Computing and Research Centre, National Chenq Kung University Taiwan, Taiwan

May/Mei 1984

7. DR I-LIN CHENG

China Steel Corporation, Taiwan

Mar 1984

8. PROF. M COHEN

Department of Materials Science and Engineering, MIT, Cambridge, USA

Oct/Okt 1983

9. DR J COLWELL

National Bureau of Standards, Washington DC, USA

Apr 1984

10. PROF. 0 EICK

Dental Faculty, Tulsa, Oral Roberts University, Oklahoma, USA

Feb 1984

11. PROF. A EISENBERG

Department of Chemistry, McGMl University, Montreal, Canada

Feb 1984

12. DR D A EVANS

Steatite and Porcelain Products Ltd., UK

Jun 1984

155

PROF. T EVANS university of Reading, UK

Mar 1984

DR J FENNER Th toldschmidt GaBH, West Germany

Oct/Okt 1983

MR/MNR A GREGORY Coherent Radiation, West Germany

Feb 1984

PROF. H W HENNICKE University of Clausthal, West Germany

Sep 1983

DR M N JAMES Department of Metallurgy and Materials Science, University of Cambridge, UK

Apr 1984

DR R D JOHNSTON BNF Metals Technology Certre, Oxfordshire, UK

Feb 1984

MR/MNR J LENAERTS 'International Defense Review', Switzerland

Jun 1984

OR L M LEVINSON General Electric Company, Research and Development, Schenectady, New York

Aug 1983

DR CHOH H LI National Science Council, Taiwan

May/Mei 1984

PROF. MIN-SHYONG LIN Department ft Institute of Electrical Engineering, National Tsing-Hua University, Hsinchu, Taiwan

May/Mel 1984

MR/MNR T N LUNG Industrial Technology Research Institute, Taiwan

Apr 1984

PROF. P K PREDECKI Denver Research Institute ft Department of Chemistry, University of Denver, USA

Mar 1984

PROF. A RABENAU M « Planck Institute for Solid State Research, Stuttgart, West Germany

Oct/Okt 1983

MISS/MEJ. G SCHIRGE CSIR Liaison Office/UNNR Skaketkantoor, Bonn

Oct/Okt 1984

PROF. J SILCOX College of Engineering, Cornell University, Ithaca, New York, USA

Nov 1983

PROF. J SINGER President, Technion, Israel

Aug 1983

MR/MNR G TURBE 'International Defense Review', Switzerland

Jun 1984

DR U J VAN BILJON CSIR Liaison Office/UNNR Skakelkantoor, Bonn

Feb 1984

MR/MNR P UU Industrial Technology Research Institute, Taiwan

Mar 1984

PROF. CHING-YUAN HU Institute of Electronics, National Chiao-Tung University, Hsin-Chu, Taiwan

Mar 1984

NIHR STAFF NIHN-PERSONEEL

Chief Di rector/Hoofdirekteur

J B Clark DSc

Deputy D1rectors/Adjwik-O1rekt«tre N R Comins PhD J T Fourie DSc

S Hart PhD

Heads of Divisions/Afdelingshoofde H Booyens PhD - Electronic Materials/Elektroniese Materiale

N R Comins PhD - Metals/Metale J T Fourie DSc - Materials Characterizat ion/Materiaalkarakterisering

S Hart PhO - Ceramics, Glass and Phase Studies/Keramiek, Glas en Kasestudies

Institute Secretary/Instituutsekretaris P S Morsner

Liaison and Infonutlon Officer/Skakel- en Inligttngsbeanpte 4 N Swart BA (Hons)

Research Scientists/flavors ingswetenskaplikes

J I Albain MSc A R Hardinq PhD E Potqieter BSc J G Auret BSc (Hons) P D Hicks BSc (Met Eng) M A Res PhD W 0 Barnard BSc (Hons) H G C Human PhO P W Richter PhD N 0 Barnett BSc (Hons) A B J Ivanfy BSc (Chem Eng) D E C Pagers PhD J Bednarik MSc R D Jenkins PhD C Schildhauer BSc A P Bent ley PhD D E Jesson BSc (Hons) Y Sentarli BSc (Met Eng) J M Benson BSc (Hons) D S Jones PhD M P Shaw PhD F Blum PhD A I Kingon PhD I Siqalas PhD J H Booyens PhD A N Kirkbride BSc (Hons) (Met Eng) P M Smit BSc A P Botha PhD E Kock BSc (Hons) N Sonnenberg BSc (Hons) C J Botha BSc (Hons) A M Lichkus BSc C M Stander PhD R J Brown BSc (Hons) A Louw BIng (Hons) (Etek) R J Stead BSc (Hons) C Claase BSc R Lowe BSc (Hons) G F Steyn BSc (Hons) P R Clayton D Phil M A Marais BSc (Hons) N A Stone BSc (Hons) J H Dalton PhD J I McQueer BSc (Hons) J A Strauss MSc C M Demanet PhD A A Meintjes BSc (Hons) H J Strydom BSc L A de Picciotto BSc (Hons) C B Mills BSc (Hons) I le R Strydom MSc D R de Villiers BSc (Hons) Y Milo MSc M M Thackeray PhD D J de Wet BSc (Hons) G Mpepo BSc (Hons) J T Thirlwall BSc MBL W Drijfhout BSc (Elec Enq) R J Muller MSc M E Thomas MSc N P Ferreira PhD A J Nepqen Blng (Hons) (Elek) 1 L van Maarseveen BSc H Fidos DSc (Met Enq) V A Nicholas BSc (Hons) G Vekinis BSc (Hons) J W Fourie MSc E Norval MSc A Wells PhD D B Goldman PhD S D Olsen MSc A J Willis MSc L D V Grant BSc (Hons) J Pierrus BSc (Hons) F T Wybenqa MSc

S C Yates BA (Hons) Chem & Maths

158

Tedwical Staff/TegMese Persantel

R H Andrews App. M 8 Beroer MS Sert (KT) 0 C Bishop NST (Hech Eng) 6 Harding D Hope NOT (Keen Eng) J N Kenworthy J HacGibbon App. (Elec) L H Oosthyizen

H J Otto P Rossouw H D H Schónberger H Snyders BSc N 0 Standen BSc J A Tennant NTS 4 P J Terblanché NOT 3 U N H v/d Berg BSc (Hech Eng)

R van Oevere» HTS R J I « I Rensburg A Vlachos GCE J U t k p m NOT (Elec Eng) E N Wilson K N Hoods N f» Young NOT (Elec Eng)

Adarfftistrative Staff/Aaainistratieite Personeet

S H E Brand J J Brauckmann N J Chi lcot t A N Dorl ing C L d u Toit M A Foman

E L Fouche n L Hendrikse M A Jones M Krtiger S HacGibbon T J Magi I I

F 6 Ober«eyer E Pick F Reinhardt S J Stephan M S Taverner H A D Visser

Services Staff/D'enste Persoaeel

N D Bopape H T Chiloans S Lerutla L N Makolj H P Males*

J Nanasoe J D Hashigo P M Holefe R P Nkgomba S Papo

R N Poo J Rabothata M S Rawano H I Sekhabi

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ANNUAL REPORT 1984 JAARVERSLAG CS>\^ - SMAT12

Documents