C. Grant Willson- Shock Compression Synthesis of Hard Materials

8/3/2019 C. Grant Willson- Shock Compression Synthesis of Hard Materials

http://slidepdf.com/reader/full/c-grant-willson-shock-compression-synthesis-of-hard-materials 1/29

A N R C P- 1 9 9 9 - 1 3March 1 9 9 9

Amari l lo National

Resource Center for PlutoniumA Higher Education Consortium of The Texas A&M University System,Texas Tech University, and The University of Texas System

r RECEIVED

This r epor t w a sprepared wi th th esupport o f the U.S.Depar tment o fEnergy (DOE),Cooperat ive

Agree ment No.

However, anyoptnions, findings,co nclue40ns, orrecomlmend ations@xpwssed here in arethoisa8o f t h eae:tihol;(s) and d o n o tne t@esea Iy re f 1ect

ThlL work was con-d:u.etedI hr ough th ek mm M !o N W onal

DE-FC04-95AL85832,

the Y ~ W S 'f DOE.

APR 0 5 1999

OS-61

Shock Compression Synthesis ofHard Materials

C. Grant WillsonDepartment of ChemistryThe University of Texas

Edited by

Angela L. Woods

Technical Editor S$ER

60 0 South Tyler Suite 800 Amarillo, TX 79101

(806) 376-5 533 Fax: (806) 376-5 561http://www.pu.org

http://www.pu.org/

http://www.pu.org/



This npon was prepared as an account of work sponsored by an agency of theUnited States Government Neither the United States Government nor any agencythereof, nor any of their empioycts. makes any warranty, express or implied. orassumes any legal liability or responsibility for the accuracy, cornplctenus. or w-

fulntss of any information, apparatus, praiua, or proccjs disclosed. or rrprrscnts

that it s use would not infringe privately owned righu. Reference herein to any spe-cific commercia1 product, prous, or &a by trade name. wadanark, manufac-t u m . or otherwise does not necessarily constitute or imply it s cndonnnent. recam-mendation. or favoring by the United States Government or any agency themf.T h e views and opinions of authors exprrsscd herein do not n d l y tate orreflect those of the United States Government or any agency thcmf.



DISCLAIMER

-Portions-of-this-document-may-be-illegible

- _ _ -- - --in-electronic-image products: Images areproduced from the best available original

document. -



ANRCP-1999-13

AMARILLO NATIONAL R ES OURC E C ENTER F OR P L U T O N W

A HIGHER EDUCATION CONSORTIUM

A Report on

Shock Compression Synthesis of Hard M aterials

C. Grant Willson

Department of ChemistryThe University of Texas

Austin, TX 78712

Submitted for publication to

ANRC Nuclear Program

March 1999



Shock Compression Synthesis of Hard Materials

C. Grant W illson

Department of ChemistryTh e University of Texas a t Austin

Abstract

adapt the high explosives technology that wasdeveloped in conjunction w ith nuclearweapons programs to subjecting materials toultra-high pressures and to exp lore the utility

of this technique for the synthesis of hard

materials.

collaboration with researchers at theUniversity of Texas, Tex as Tech Universityand Pantex (Mason & Hanger Corp.). Thegroup designed, m odeled, built, and tested a

The purpose of this research was to

Th e research was conducted in

new device that allows quantitative recoveryof grams of material that have been subjectedto unprecedented pressures. Th e mod elingwork was don e at Texas Tech and Pantex.Th e metal parts and material sam ples weremade at the University of Texas, and Pantexmachined the explosives, assembled the

devices and conducted th e detonations.Sam ple characterization w as carried out a t theUniversity of Texas and Texas Tech.

. ..

..11



TABLE OF CONTENTS

1. EXPERIMENT ........................................................................................................................ 1

2.CONCLUSIONS ...................................................................................................................... 9

2.1 Future Work ....................................................................................................................... 9

REFERENCES ............................................................................................................................ 1 1

...111



LIST OF TABLES

Table 1:- S-unmary-o€Samples-Compressed.................................................................................L~ ~ 5

iv





1. EXPERIMENTTw o conventional explosives have

traditionally been used to providecompression in nuclea r devices. The earlyweapons were constructed of formulations

based on HMX, tetra(methy1enenitramine).This material was replaced by T ATB, 1,3,5-triamino-2,4,6-trinitrobenzene n later weapondesigns. Our application for these explosivesis very similar to the purpose for which theywere originally designed , a means ofproducing intense pressure through shaped

charge detonation. The detonation of

carefully designed shaped charges canproduce enormous compression andtemperature pulses. Our intention was to

exploit the exp ertise and the technology thathas been developed in the manufacturing andmod eling of such devices for use in ignitionof nuclear weapons, to adapt the explosivesand that technology to g enerate the high-pressure conditions required for the synth esisof metastable mate rials. W e had to design anew tool (device) for this purpose.

Th is tool was u sed to compress C,, inan attem pt to transform that material into thediamond allotrope. W e also used the tool inan attemp t to synthesize the cubic phase of

carbon nitride. First, principle calculationshave predic ted that p-C,N, could have ahardness equal to, or greater than that, of

diamond. Previous low-pressure synthesisexperim ents have fa iled to gen erate thismaterial on a macroscopic scale. High

pressure and high tem perature techniqueshave often been used to generate and study

dense and hard solid phases, although theiruse in the synthesis of carbon nitride has notbeen extensively explored. Recent theoretical

work predicts that the desired p phase ofcarbon nitride is likely to be more stable athigh pressure. Hence, our new shockcom pression technique provided an excitingpotential for gene rating this valuable, butelusive compound.

Research on the consolidation ofpowder and syn thesis of m aterials undershock pressure is still in its infancy. The first

report of such research was by the Russianscientists Pashkov, et al. (1979). Rep orts ofpioneering research on shock co nsolidation ofpowders in the United S tates first appeared inthe early 1980s in th e work performed by

Davidson et al. (1982) Schw artz et. al. (1984)and Ahrens et. al. (1986). Reg ardless of thedetailed nature of the research, the m ajorissues that must be con sidered in performin gthe shock consolidation and sho ck synthesisexperim ents are: (1) th e shock delivery

system, (2) the size and con figuration of the

sample, and (3) the sample containment andholding fixture design. Th e pressing issuesare the reprodu cibility of the experim ents, the

consistency of shock pressure andtemperature achieved, and of course, th e.recovery of the sho cked sam ple for post-consolidation analysis is a critical issue. Theshock delivery system s reported in th eliterature include planar loading andconvergent loading systems. The planar

loading techniques use de livery systems suchas single stage gas guns, propellant guns, twostage light gas guns, and explosively drivenflyer plates as reported by Do dson et. al.

(1982), Chabildas and Hills (1986), and Nellis

et al. (1986). In these experiments, the shockmust produce a controllable, reproducib le,high-pressure, and flat shock front.

Sample recovery must be carefullyconsidered in th e design of the loa ding system(Duvall and Graham, 1977). The recoverysystem is designed to eithe r control the rate ofpressure release or to dece lerate and capture

the sample holding fixture. Recovery systemsare generally complex struc tures that in turn

make it difficult to predict or measure the

magnitude and direction of the shockdelivered to the sample.

fullerenes have become readily available,many successful experiments have beenconducted that have generated diamonds fromC,,(Hirai, et al., 1993; Sekine , 1992;Bocq uillon, et al., 1993; Hode au, et al., 1994;Regureiro, et al., 1 992; Ma , et al., 1994;Yoo,

Sin ce bulk quantities of C,, and other

1



et al., 1992; He, e t al, 1995; Mukhanov e t aI.,1996; Kozlo v, et al., 1996). Regueiro andcowo rkers (1993) found that the

transformation from C,, o diamond occurred

with “fast kinetics and high efficiency”evenat room tem perature under “moderate”pressure. Hirai and coworkers’ shock loadedC , and recovered diamond c rystallites withno eviden ce of a transition from CcA ,ographite or reversion to grap hite fromdiamond. Recently, He et. al. (1995)

reported that C,, cou ld be converted todiamond with 100% yield when mixed withnanometer grade nickel and compressed by aone-dimensional plane wave generator. Thenanometer grade metal (Ko zlov, et al., 1 996;Sinfelt, 1977;Du, et al., 1991; Anderson, etal., 1980; Gong , et al., 1991) (metal whoseparticle size is between 1 nm and 100 nm)was used as a tem perature quenching agent,and is designed to suppress any reversion ofthe high pressure phase during pressurerelease (Hirai, et al., 1993; Bundy, 1980;Kurdyumov, et al., 1988). T he most popular

metals or alloys from Group VJII due to theirhigh cata lytic activity in a number of other

processes (Bocquillon, et a]., 1993; Kozlov , etal., 1996; Bundy, 1980). This group of metalscan not only serve as a quenching material,but can also act a s a carbon solvent andthereby promote diam ond nucleation (Li, etal., 1993). In particular, Group VIII metalswith extremely high surface areas have shownpromise as “catalysts” in diamond synthesisby sho ck compression (He, et al., 1995).

the past several years to synthesize P-C3N,in

macroscopic amounts. The majority of thesesynthetic efforts have focused on lowpressure, thin film growth. These attemptsinclude sputtering with several variants,

(Torng,et al., 1990; Chen, et al., 1992;Nakayama, et al., 199 3; Yu, et al., 1994; Yen,et al., 1995; Li, e t al., 1995) electron beamevaporation of carbon coupled with nitrogenion bombardment (Fujimoto and Ogata, 1993;Chub aci, et al., 1 993), and delivery of carbon

quenching materials have traditionally been

1

Num erous attempts have been mad e in

via pulsed laser ablation to a high fluxnitrogen stream (Xion g, et al., 1993; Niu, Lu

and Lieber, 1993; Narayan, e t al., 1994; Ren,et al., 1995; Lieber and Zhang, 1995; Zhang,

Fan and Lieber, 1995;Zhang, et al., 1996).High pressure and high temperaturetechniques provide an alternative mechanism

.to probe the formation of the sp3 ondedcarbon nitride. This procedure should beanalogous to the synthesis of diam ond byshock compression of sp2 raphite or othercarbon containing materials. In fact, recenttheoretical studies have sug gested that carbonnitride with sp3 onding sho uld exhibit greaterstability at high pressures (Te ter and Hem ley,1996; Bad ding and Nesting, 1996). However,only a few experimental attem pts tosynthesize carbon nitride using high pressurehave been reported (Sekine, et al., 1990;Badding et al., 1995). No evidence of carbonnitride has been detected in the compressionproducts from these studies. Startingmaterials have consisted of various organicprecursors, with the em phasis placed on the

ratio of carbon to nitrogen. We, therefore,chose to investigate the use of the newpressure environment as a possible synthetic

route to the elusive, ultra-hard carbon nitride.Compu ter mo deling was used to assist

in the design of an explosive and w orkpiececonfiguration that could survive the extrem econditions experienced during the explosion.In this context, the term “w orkpiece” is usedto describe the com bination of materialscontained within the explosive shell. DynaEast Finite Element L agrangian (DEFEL)hydro-code was used to determine the bestdetonation pattern to achieve uniform

implosion of the workpiece. DEFELcalculations provided a two-dim ensional axi-symm etric simulation of the process intendedto predict the number and location of thedetonators needed to produce the sym metric

coIIapse of a spherical shell. The CTH familyof codes was used to accurately model thecompression and recovery stages. This three-dimensional code is most comm only used tomodel the com pression required to initiate the

2



detonation of nuclear weapons. Previous

model studies of this process were only

concerned with the compression process,since once com pression was achieved, nuclearreaction ensued. W e had to model both thecompression cycle and the im portant eventsoccurring during decompression.

Mod eling the propagation waveprovides an estimation of the magnitude andduration of the pressure and temperature pulsedelivered to the sample. The magnitude ofthe pressure pulse is such that it cannot bemeasured directly by experimental means. Itcan only be estimated through such m odeling.Simu lation of the decom pression processprovided input in to the design of a w orkpiece

that could survive the huge tension forcesgenerated during unloading. The simulationsallowed us to exp lore a wide variety ofgeometries.

attempt to achieve a workpiece that was

recovera ble after the explosion. Trial 1 wasconstructed using a pressed 0.25 inchdiameter graph ite sphere enclosed in a 1O

inch diameter copper shell. The copper shellwas assembled from hemispheres. It was

encased in a sphe rical shell of a 16Ogexplosive that was p recisely machined andassembled with epo xy glue. The graph ite todiamond transition requires only about 20

GPa. The mod eling code showed that thegraphite would experience a compression

pulse of approximately 150 GPa for 2microseconds. The calculations showed thatthe copp er shell would experience a tensionstress of about 20 GP a on decompression, farexceed ing the spall strength (5 GPa) ofcopper. As predicted, the copper spherefractured into many pieces (dust)!

The second trial design incorporated asteel shell surround ing the copper sphere and

a brass shell surrounding the explosivematerial. Ho les were cut through the brassshell to accommodate the detonators. The

steel shell significa ntly increases the spa11strength of the workpiece. (See Figure 1).

Various design s were considered in an

The addition of the brass jacket surrou nding

the explosive was the key to success. It was

employed to reduce the magnitude of th etension waves transmitted throug h theworkpiece after com pression. Deton ation of aspherical shell shaped charge results in thegeneration of two pressure waves. One isdirected inward and results in com pression ofthe carbon sample. The secon d is anexpansion (tension) wave that travels outwardfrom the explosive surface. The brass shellserved as a sacrificial structure. It wasefficiently destroyed by this expand ingpressure wave. Though destroyed, it servedto reflect a portion of the exp ansion w aveback toward the sample. Th is reflected pulse

was a compression wave, direc ted toward thecenter of the workpiece. Th e distance fromthe brass shell to the copper/steel work piecewas precisely controlled such tha t thereflected compression wave generated from

the brass surface reached the su rface of theworkpiece at the same time as he reflectedtension wave that was propagating from thecenter of the sample. The se wavesdestructively interfered in the w orkpiecematerial, thereby reducing the m agnitude ofthe tension waves below the spall strength ofthe sample holder and preventing failure. Theassembled device (Figure 4) was buried insand. The sand surrounding the workpieceprovided a surface that augmented reflectionof the expansion waves and it served tocontain the sam ple holder.

experiment resulted in a new failure mode.The copper/steel chamber w as recovered intwo hemispherical pieces. Th e work piecefailed at the junction where the m etal

hemispheres were assembled . This was adramatic improvement over the firstexperiment, in which the sample chamber

failed catastrophically. The new result

showed that the dimension of th e gap betweenthe outer brass shell and workpiece wascalculated correctly so that the inwardlypropagating compression wave was properly

timed to destructively interfere with the

Unfortunately, the second compaction

3



outwardly propagating tension wave withinthe steel shell. Th e cancellation wassufficient to prevent the steel from fracturingin tension. Althoug h fragmentation did not

occur, the w orkpiece was not recoveredintact, resulting in the loss of the carbonsample. Th e cau se of the dissection becomesmore evident with a description of themanufacturing process for the workpiece.

The workpiece consisted of fiveindividual pieces: a spherically pressed pelletof C,, and two hemisphe rical she lls, one ofcoppe r and one of steel. In order to assem blethe w orkpiece, the sample pellet wasencapsulated by the copper hemispheres as

shown in Figure 1. Figure 2 shows the actualcomponents before assembly. The assemblywas placed inside the two steel hem ispheres,which were epox ied together at the outerseam to form the final workpiece. It was

expected that the high temperature andpressure exp erienced during detonation wouldbe sufficient to “weld” the two halvestogether. Ana lysis of the product show ed thatunfortunately this junction actually served asa propaga tion point for failure duringdetonation.

The third design iteration consisted ofa single change fro m the previous experiment,that being rotation of the steel cover such thatits junction was perp endicular to the seamformed by the two copper hemispheres. Thatworkpiece fragmented into four equal,quarter-spherical pieces and the carbonsample was lost. This failure was caused by a

phenomenon called “jetting.” Machining

imperfections preclude the steel hem ispheresfrom fitting together with no resulting gaps.

Upon detonation, hot, expand ing, highvelocity gas accelerated through the gap s andcut through all the material beneath the steel.The high velocity gas has enough energy tocut through all the material beneath the steel.Thus, the copper sphe re was cut in half alonga plane containing the steel junction. Inaddition, the co pper did not fuse together aspredicted, and it failed at its seam. Hen ce, thefour parts.

The fourth workpiece designincorporated a single solid steel spheredesigned to minimize jetting. In order tointroduce the sam ple material, a hole was

drilled to the center of the steeI sphere. Thediameter of the drill was the s am e as hedesigned diameter’of the spherical samplechamber. The drilled section was rounded atthe bottom to form a hemisphere. The samplematerial was inserted into the cen ter of thesteel sphere and the hole w as then closed w itha threaded screw that had the bottom tiphollowed to form a hemisphere. Aftertightening to the maximum torque possible,the top of the screw was cut, rounded , and

smoothed until it was flush with the outersurface of the steel sphere. This resulted in aspherical sample contained in the center of anessentially seam less workpiece as shown inFigure 3. Figure 4 shows what the assembled

system looks like just before detonation.The fourth shot resulted in complete,

intact recovery of the wo rkpiece as shown inFigure 5. The m arkings on the surface of thesteel resulted from converging shock frontsgenerated at each detonator site. Fourteendistinct polygons were formed with the center

of each polygon correspond ing to the locationof a detonator. Th e spheres recovered fromsubsequent trials-had exactly the samephysical characteristics.

The final design subjects the sam ple toa m aximum com pression of 230 GPa (as

predicted by the CTH code). Th e duration of

this pulse is approximately 4 p as shown in

Figure 6. A second, less intense compression

pulse is eviden t at between 20 an d 30p.This second compression wave is the result of

reflection of the expansio n waves from thebrass shell. The calculations associated with

, the second peak are complex and somewhatsubjective. Therefore, the m agnitude andduration of this peak are still being studied.No changes were made to the design for anyof the remaining experimen ts (only thestarting ma terials were varied) so the pressure

4



DiamondSynthesis

ExperimentShotD1

Shot D2

ShotD3

Shot D4

Shot D5

Shot D6

Shot D7

Shot D8

Amount of

(by weight)

Amount and Type of Quenching M aterial

-C60a , (by weight)

50% 50% -200mesh copper

50% 50%nanograde nickel

50% 50% -200 mesh nickel

50% 50% nanograde cobalt

20% 80% nanograde nickel

50% 50%nanograde nickel ’ nd 0.5 mm diamond seeds

20% 80%-200mesh nickel [compressed sample]

20% 80% nanograde nickel [compressed sample]

Carbon Nitride Synthesis Experiments

ShotCN1Shot CN2

2-Amino- 1,3,5-triazine - C,N,H,

Tetracyanoethylene- C,N,

b. nan ograde nickel: 99.3% pure, particle size of 10-20 nm;c. nanograde cobalt: 99.5% pure, particle size of 15-25 nm.

delivered to the samp les in all shots was thesame as that for Shot Dl.

Eight exp eriments designed tosynthesize diamond and two compactions

designed to gen erate carbon nitride wereperformed. The starting materials for eachexpeTiment are dE E ib X iii Ta bl e 1.

center of the workpiece, the steel sphere wasIn order to extract the sam ple from the

machined- intotwiecestoexpose thesamp le cavity. This is difficult because thesteel becomes extremely hard in areas nearthe center of the workpiece. The spheres

-w ere-cut cross-their-entire-circu-mfeTeEe nd

sawed radially inward to a point just outside

the sample cavity. This process can consume -as many as six hiph speed steel saw blades-for -a single workpiece! The location of thesamp le cavity was d etermined from analysisof an X-ray taken of the recovered workpiece.From the X-ray, the sam ple chamber appearsmuch lighter than the surrounding steel andthe distance from the outer surface of thesphere-to-the-sample-chamber an be easilyestimated. When the saw ing reached the

point when just a thin layer of steel (1/16”)was holding the workpiece together, thesphere was “cracked” into two hemisph eresusing a chisel and hammer. Care was taken to

ensure that all particles that were d islodgedduring~~ this process were re cox ed-f or-_ ~ ~~

analysis.

states. If the amount of ~quenching-mate&lw.aslox ,..&e-sample-was ecovered-in-a-- - -~

powder form that could be directly analyzed.If the amount of quenching m aterial was high,the carbon sample was trapped in the m oltenq u ezh i ig ma te r idT~u?ingthe-detonation.--

Separation of the carbon sample from themetal- equires-dissolving-the-~ metal-in-an-

~ _ap.p~opriate_solxent-The-hemispherescan, -inprinciple, be dissolved in boiling HCI andsubsequently filtered to prov ide the carbonproduct. Stainless steel is not designed toeasily corrode, so this process does not easilyproduce a clean sample. An alternative todissolving the entire hemisphe re was to drillportions of the sample material out of theshell and collect the cuttings. The cuttings

The samples were found in one of two

5



were dissolved in HCl and the resulting

ExperimentShot D1

mixture- ~ centrifuged.~ . _ - ~~ ~ - _he liquid- ~ was pouredoff, leaving only the carbon s amp le, which

ProductNanocrystalline graphite (- 30 nm)

was washed to a pH of 7 and then dried for

analysis.X-ray scattering and Raman- -

spectroscopy were used to determine thestructural ch aracteristics of the m aterialsrecovered from the explosions. X-ray

diffraction stud ies were performed using a

Philips PW 1729X-ray generator operating at40 kV and 40 mA to generate Cu-K,

radiation. The diffracted-radiationwascollected via a Philips APD 3520 scanning

detector. A second x-ray analysis for Shot 0 7

was done on a ScintagXI iffraction system(40 kV , 40 mA ) with a theta-theta powderdiffractome ter fitted with a solid state Si(Li)detector. All x-ray sam ples were prepared by-spreading the samp le in powder form on glasssubstrates using am yl acetate (used to helpsecure the powd er to the glass substrate).Spec tra were taken using a scan rate of2"/min, unless o therwise noted.

performed on powd er samples using a

coheren t 1-200 Argon laser ex citation so urceirradkting the solid sample at 457 nm. The

light was passed through an AppliedPhotop hysics pre-monochromator to filter theplasma lines. The scattered light wascollected by a N avitar f/0.95 cam era lens anddispersed through a Sp ex Triplemate three-stage spectrometer containing a 1600

_ _ _ - ~- _ _ _

Raman spectroscopy studies were

Shot D2Shot D3

Shot D4Shot D5Shot D6

grooves/mrn grating. The dispersed light wasdetected by a Ph otometrics CH-2 10 liquidnitrogen cooled~ CC D.MicroiRaman--~ ~ ~

spectroscopy was carried out on the in terior

walls of the workpieces as well. Wavelengthso f 5K 5 n m and-488~ iwere-generated-with------- - ..... . .

an argon-ion laser and w ere directed on thesamples using a ba ckscattering Ramanmicroscope. The scattered light wascollected,-passed-through-a-holographic-notch-

filter, and dispersed through a single gratingmonochromater.- ~ The light- was detected in a_ - ulti-channelcobfiguration by a liquid~.. .nitrogen cooled CCD de tector.

recovered sample is shown in Figure 7. The(002) diffraction of graphite is eviden t in the

peak at 28 = 26.58". A typical Ram anspectrum of Shot DI is shown in Figure 8.

-The pe& at 1570 cm-' is due to zone-centervibrations in g raphite and is referred to as theG-band. The peak at 1351 cm-' correspon dsto zone-edge vibrations that become Ramanactive in the disordered and microcrystallinephases of graphite. The Tuinstra and Koenig(1970) model was used to determine theaverage graph ite crystaIIite size based upon

the relative intensities of the D and G bands.The ratio of the areas of these two peak s has

been used to estimate a nanocrystallite size of30nm for ShotDI.The results from the ten-compaction experimen ts are shown in Tab le2 .

- - - ~

A typical x-ray diffraction pattern of a

Nanocrystalline and disordered g raphite (- 25 nm)No carbon phase detected

Highly amorphous graphite (< 3 nm)Highly amo rphous graphite (< 3 nm)Crvstalline diamond. sraDhite. and nanoc rvstalline graDhite (- 10nm)

Table2: Carbon Phases as Determined bv X-Rav and Ram an Spec tral Analysis

Shot D7

Shot D8Shot CN1

Shot CN2

Nanocrystalline and disordered graphite (- 10nm )

Nano crystalline and disordered graphite (- 5 nm)

Highly amorphous graphiteNo carbon Dhase detected

6



Eight com pression experiments wereconduc ted with the goal of con vertingC,, todiamond. Diam ond was only recovered in theexperiment in which diamond seeds were

added to the starting material (Shot06). -ray results showed that so me diamond wasstill present in that sam ple after detonation.

Therefore, the co nditions generated are not

completely hostile to diamond. Thecompression in all of the experiments wassufficient to result in the quantative loss of thefullerene phase. How ever, only graphitic andamorphous carbon could be recovered. Thenature of the com paction produced by thisparticular workpiece design does not app ear

to be app licab le for the synthesis of thediamond phase.

Tw o exp lanations are consistent withthe experimental findings: either the carbonsamples never entered thepressurehem perature region of diamondstability, or the diamond region of the phasediagram was reach ed, but the diamond phasewas lost due to subsequent phase transitions.We believe that the magnitude of thecompression was sufficient to reach theportion of the phase diagram best described as

“liquid carbon (M itchell, et al., 1986; Bundy,1989). Despite our best efforts to quench the

sample into the diamond phase, the design ofth e workpiece did not allow the temperature

to be reduced at the rate necessary to enter thediamon d region. It is also possible that even

though the sam ple experienced thepressurehem perature conditions in whichdiamond is thermodynamically favored, the

time the sample was m aintained in thiscondition was less than that spent within thegraphite portion of the phase diagram. Thiscould again be attributed to insu fficient

quenching, or possibly du e to a phase changeresulting from the seconda ry compression.

an attempt to generate carbon nitride fromstarting materials containing carbon andnitrogen. Th e detonation of the shapedexplosives did not p roduce well-crystallizedproduct. Instead, predom inantly amo rphousmaterial was recovered. The se materials aresimilar to those recovered from the diamondsynthesis. The product appears to form while

in an undesired region of the phase diagram.

configuration did not contain a sample.Instead a solid stainless steel sphere wasplaced at the center of the explosive anddetonated. Figure 9 shows that a void wasgenerated in the center of the steel sph ere.Hardness measurements show that thematerial near the void in the center is harderthan the starting material.

sample can be altered by changing the amount

of explosive and by changing the dimensionsof the workpiece. The conditions generatedusing the current design produce extrem elyhigh pressures but is apparently no t suited to

forming the desired products. Mo difying thedesign could provide the proper compressioncycle required to synthesize one or both of th edesired ultra-hard materials.

Two experiments were conducted in

The final shot using this workpiece

The pressure pulse delivered to the

7





2. CONCLUSIONS

constructed a workp iece that can withstand

the explosion and contain the sample. This

device allowed us to recover materialssubjected to unprecedented pressures.However, the temperature quenching rates ofthe cu rrent design are insufficient to produce

diamond or P-C3N4. Graphite and c60 areconverted into disordered or nano-crystalline

graphite by this process. The extremecompression conditions have produced steelwith hardnesses that exceeds that of high-

strength steels mad e by more conventionalmeans.

We successfully designed and

2.1 FutureWork

measurements are still underway. Figure 10

shows Vickers hardness results for the sam ple

(MAH 38) that contained 50% C and 50%Ni. The figure shows the hardnessdependence as a function of position withinthe workpiece and sample. We are attemptingto correlate hardness with structuralcharacteristics.

Extensive hardness testing

A new design has been com pleted forthe work-piece. Our intention was to use thisworkpiece to produce a super-hard coatin g on

a stainless steel sphere. Figure 11 shows across-section of the assem bled workpiece.The 2” diame ter stainless-steel shell is m adein two pieces that are tapped and threaded,respectively. A tungsten carbide powder waspressed into a sphe rical shell - 2 mm thick on

the inside of both halves of the workpieceusing a spherical die. A stainle ss steel ballwas placed in the center of the cavity, and thetwo halves were screwed together.Simulations were used to calculate theamount of explosives necessary to p roduce auniform compression. Pantex is machining

the high explosives necessary for thisexperiment. Six workpieces are beingconstructed and may b e tested. A designincorporating copp er as the workpiece

material was also developed. The copperworkpiece would facilitate the reco very ofcarbon phases and the la rger geometry wouldreduce the maximum pressu re created at thecenter of the workpiece. W e hope that thisconfiguration will su ccessfully synthesize thediamond phase.

9





REFERENCES

1. T. J. Ahrens, N. Thadnani, A. H. M utz, T.

Vreeland, R. B. Schwartz, J. A. Tyburczy,

S. Shastri, and T. C. Peng, “Shock

Consolidation of Aluminum-LithiumPowder,” in M etallurgical Applications ofShock Wave a nd High Strain RatePhenom ena, 1986 , pp. 83 - 106.

-. . -. . .. ~ - -

- -2; -Anderson;A:,-Hunderi; O ,- and Granqvist,

C. G., J. Appl. P hys. 57 ,75 7 (1980).

4. Badding, J.-V., Parker, L. J. , and Nesting,~ D. C . 1 Solid State Chem.-lt7; 229~ (1995).

-

-

5. Bocquillon, G., Bogicevic, C., Fabre, C.,anaXassat, A.ZPhy1Chem. 97,12924

k

(1-993).

6. Bundy, F. P., Physica A 156, 169 (1989)

7. Bundy, F. P. J. G eophys. Res. 85,6930

(1980).

8. L. C. Cha bildas and C. R. Hills,“Dynamic S hO&-S tE diGof Va nadiu m,”

in Shock Waves in Cond-ensedllllatter,

edited by Y. M. Gupta, Plenum Press, NY

__. -

(1986), pp. 429 - 448.

--g7Chen,-M;+n;-XTDravid; V. P., Chung.

Y. W., Wong, M. S., and Srou l, W. D.Su@ Coat. Technol. 54155,360 (1 992).

in Shock Waves in C ondensed Matter,edited by W. J. Nellis, L. Seam an, and R.A. Graham , American Institute of Physics,NY (1982), pp. 67 - 71.

12. B. W. Dodson, C.Arnold, E. L. Venturini,and P. M. Lenahan , “Post-ShockChemical and ESR Analysis of

Acrylamide and Selected Anthracene--Serivatives,”-in-ShockWaves in

Condensed M atter, edited-by W. J. Nellis,L. Seaman, and R. A. Graham , Am ericanInstitute of Physics, NY (1982), pp. 423 -

-424. - - - - -

13. Du, Y., Xu, M., Wu, J., Shi, Y., and Lu,

H., J. Appl. Phys. 70,5 903 , (1991).14. G. E. Duvall and R. A. Graham , “Phase

Transitions Under shock Wav e Load ing,”

Reviews3f Mod em Phys ics 49 ,6 7 (1977).

Phys. 32, LA20 (1993).15.Eujimoto, F. and Ogata, K., Jpn. J. Appl.

16. Gon g, W., L i, H., Zhao, Z., Hadjipanayis,G. C., Papaefthymiou, V. P., K ostik as, A.,and Sim opouo s, A., J. Appl. Phys. 70,5900, (1991).

17. He, H., Jin, X., and Sh en, Z., J. Mater.

Science L ett. 1 4 , 913 (1995).

18.- Hirai,- --., Kondo, K., and Ohwada, T.,

19. Hod eau, J. L., Tonnerre, J. M., Bouchet-

carbon 31,3095(1993).

Fabre,_B., Regueiro,-M. N., Cappo ni, J. J.,and Perroux, M., Phys. Rev. B. 50, 10311(1994).

20. Kozlov, M. E., Fons, P. , Durand, H. A.,10. Chubaci, J, Sakai, T., Yamamoto, T., ~ ~ ~ ~ Nozaki, K., and Tokumoto,M.,J.Appk

21. Kurdyumo v, A. V., Ostrovskaya, N. F.,and Pilyankev ich, A. N., Sou., Powder

Metal. Met. Ceram. 27 ,32 , (1988).

O g a t a ~ K ~ E b e ~ A ~ a n d f F u j i m o t o ~ J ~ ~ ~ c ~ ~- ~ P h ~ ~ ~ 8 0 ~ 1 k 1 ~ 8 2 - ( ~ 1 9 9 6 ) TInstrum. Methods B 80181, 463 (1993).

~-~ ~

--~ ~ ~ . ~ k ~

11. L. Dav idson, D. M. W ebb, and R. A.

~~. raham, “A nalysis of Capsules for - - - -- -~... . ..

R e ~ ~ v e ~ - i n ~ S ~ ~ ~ C . o m p ~ e ~ s e ~ M a t t e r , ~ ~ .. -. . - ~ - -~ - -_ _ _ _ ~--

11



-. . ..

22. Li, D., Chu, X., Cheng, S., Lin, X.,Dravid, V., Chu ng, Y., Wong, M., andSproul, D., Appl. Phys. Lett. 67,203(1995).

- - ~.

23. Li, D., Chung, Y. W., Wong,Mi Si, an dSproul, W. D., J. Ap p l . Phys. 74,219( 1 993).

24. Lieber, C. M. and Zhang , Z. J., Chem. Ind.922 (1995).

25. Ma, Y, Zou, G., Yang, H., and Meng, J.

Appl. Phys. Lett. 65 ,82 2 (1994). . .

26. Maya, L., Co le, D. R., and Hagamo, E.

W., J. Am. Ceram. SOC.74, 1686 (1991).

27. Mitchell, A. C., Shaner J. W., and Keeler,- - --- R:-N., Physica 139 & 140B, 386 (1986).-

-- - - ~- _ _ -.

Symposiumon Shock Pressure, Moscow,1979.

34, Regueiro, M, M., bello,-L.,-Lucazeau,

G., and Hodeau, J. L., Phys. Rev. B. 46,- - - - __ - - -

9903-(1992).- - -

35. Regueiro, M. N., Monceau, P., and

Hodeau, J. L., Nature 355,237, (1992).~ -

36. Ren, Z. M., Du, Y. C., Qiu, Y., Wu, J. D.,Ying, Z. F., Xiong, X. X., andLi , F. M.,Phys. Rev. B 51,52 74 (1995).

__ _-___

37~R;B;-Sch wartz~P;-ICasiraj~T~Vreelandr~ ~

~ n d T ~ J ~ h ~ % - T h ~ f o ~ i S

Wave C onsolidation of Powders,”ActaMettalurgica,32, 1243 (1984).

38.-Sekine,-T.,-Proc.-Japan.-Acad-68.~~),9_5

Buravov, L. I., Vul’, A. Y., and Yagubski,E.B., Tech. Phys. Lett. 22,731 (1996).

29. Nakayama, N., Tsuchiya, Y., Tamada, S.,

Kosuge, K., Nagata, S., Takahiro, K., and

Yamaguchi, S . , Jpn. J. Appl. Phys. 32,

L1465, (1993).

30. Narayan, J., Reddy, J., Biunno, N.,Kanetkar, S . M., Tiwari, P., and Parikh,N., Mater. Sci. Eng. 26 ,49 (1994).

31. W. J. Nellis, W. C. Moss, H. B.Rado usky, A. C. Mitchell, 1. T. Summers,E. N. Dalder, M. B. Maple, and M.McElfresh, “Properties of Niobiumrecovered from Megabar DynamicPressures,” in Shock Waves in Condensed

Matter, edited by Y. M. G upta, PlenumPress, NY (1986), pp. 7 19-724.

32. Niu, C., Lu, Y. Z., and Lieber, C. M.,Science 261,3 34 (1993).

33. P. Pashkov, S . P. Pisarev, V. D. Rogozin,and A. F. Trudov, “Shock Com pressibilityof Powders,” in Physics of ShockPressures: Proceedings Second All-Union

__. ..

39. S ekine, T., Proc. Japan. Acad 68(B), 95(1992).

40. Sekine, T., Kanda, H., Bando, Y., and

Yokoyama, M., J. Mater. Sci. Lett. 9,

1376 (1990).

41. Sinfelt, J. H., Science 195 ,427 9 (1977).

42. Teter, D. M. and Hemley, R. J., Science271,53 (1996).

43. Torng, C. J., Sivertsen, J. M., Judy, J. H.,and Chang, C., J. Mater. Res. 5,2490(1990).

44. F. Tuinstra and J. L. Koenig, J. Chem.

Phys. 53,11 26 (1970).

45. Wixom, M. R., J. Am. Ceram. SOC. 3,1973 (1990).

46. Xiong, F., Chang, R. P. H., and White, C.

W., MRC Symp. Proc. 280,587(1993).Zhang, Z. J., Fan, S., and Lieber,C. M., Appl. Phys. Lett. 66,35 82 (1995).

12



4 ~ ~ ~ e n r T ~ Y ~ n d - C - h o u 7 - ~ ~ P ~ A ~ p Z ~ P h y s .Lett. 67,2801 (1995).

48. Yoo, C. S., N e b , W. J., Sattler, M. L.,

and Musket, R. G., Appl. Phys. Lett. 61,

273 (1992)

49. Yu, K. M., ohen, M. L., Haller, E. E.,Hansen, W. L., Liu, A. Y., and Wu, I. C.,

Phys. Rev. B 49,5034 1994).

-5O:Zhang,Z. T.,TKg,P.,nd Lieber, C. M.,Mater. Res. Soc. Symp. Proc. 388,271(1995).

51. Zhang, 2. J., Fan, S.,Huang, ., and

Lieber, C. M., AppZ. Phys. Lett. 68,2639(1 996).

. .13





~~ ~~~~~~~~ . ~~.~~

:,:SAND. : : : :" :. . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . ., ' . .

s&$l_.. . . . . . . . . . . . . .

...... . . . . . . .. , . , . .................. . . . . . . . . . . . . . .. . ...I

~~~

. . . . . . ._-__-. . . . . . . .. . . . . .. . . . .. . . .

. . . .

?Steel_ _.

Fg:::::. . .

. . . . . . . . .. . . . . . . .. .. .

r,: . . . . . . . . .. . . .

. . . . . . . . . . .. . . . .

. . . . . . . . . .. . . .. . . . .. . . . . . . .

. . .. . . . . . . . .. . . . . . . . . . . . . . . .

. . . . . .

. . . . . . .. . . . . . . . . .. . . . . . . .. . . . . . . .. . . . . . . . .

. . . . . . . . . . . .

Figure 1: Second Experimental Design. m ot e, only one of the fourteen detonators is depicted.]

Figure 2: Components fo r the Second Work-Piece D esign

15



Figure 3: Design of th e FourthCom paction W orkpiece Consisting of a Solid Steel Sph ere which

has been Drilled and Tapped to the Center, Filled with Sam ple, and Closed with a Threaded Screw

Figure 4: Assembled Workpiece and Detonation Wires

16



2.50

z o o.15.0

P A D O

50

.i0

c9v

0 .

. . -50:

Figure 5: Steel Workpiece Recovered from the Fourth Compaction ExperimentThe picture on the left shows the location of the steelscrew while the picture on the right shows the

hemisphere not containing the screw.

. .. ,:::..: ..., . . , . . ..I . . " ' ' ' ' I " " . " " * . : . , . *. .

"'

-- . -

..-: -

-_ -A

. . .!..:.._..__'... . . , I . . . ...!... . . ! . ......I. . ........ .. . .. ' ... ....

17



.. ....

MI ,

Figure 7: X-ray Diffraction Pattern of Shot 0 7 after Dissolving the Shavings in HCI

[Note: Pattern was taken on Scintag X-ray d iffraction system at a scan rate of l"/min.]

1570 cm"

/

W v e n u m b e r ( c m ")

Figure 8: Raman Spectrum of D1



Figure 9: Solid Steel Shot with Void at the Center

19



Figure 10: Vickers H ardness Measurements Using a Micro-B all Indenter on a Cross-Section of

Sample MAH38 [Thedata shows very high hardness at the inner rim and then d ecreasing hardnessaway from the center.]

20



Stainless Steel Core (1”)

Tungsten Carbide (-0.1”)

Tapped and Threaded

Figure 11: New Experimental Design

Date post:	06-Apr-2018
Category:	Documents
Upload:	fraosm
View:	217 times
Download:	0 times

C. Grant Willson- Shock Compression Synthesis of Hard Materials

Documents