E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
New materials through a variety of sintering methods
Lucyna Jaworska
Centre of Materials Research and Sintering Technology,
The Institute of Advanced Manufacturing Technology,
Krakow, Poland
Solutions for Critical Raw Materials Under Extreme Conditions (CRM-EXTREME)
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
PM production in Europe by value 2010 €8.5 billion
Magnets €0.9
billion; 11%
MIM €0.5
billion; 6%
PM Struktural
Parts/Bearings
€2 billion; 24%PM Semi
Products €0.7
billion; 8%Diamond Tools
€1.4 billion;
16%
Hard Metals €3
billion; 35%
Source: B. Williams: Powder Metallurgy: A global market review.
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Researches regard ceramic materials are mainly focused on:
� improving fracture toughness of KIc
� limiting grain size in compacts
� improving properties at high temperatures
� improving resistance to thermal shocks
One of the main goals of modern ceramic technologies is still the manufacture
of dense ceramic parts with submicrometric or nanostructured grains
New materials through a variety of sintering methods
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Starting
powders
Shaped Green
BodyPolycrystalline
product
Mixing
compacting
DebindingSintering
The most important factors which have influence on ceramics properties are:
• powders – their method of obtaining and characteristics (particle size, shape
and structure)
• compacting – compression ratio, dimensional changes
• Sintering – temperature, time and the furnace atmosphere
New materials through a variety of sintering methods
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Traditional and new techniques of the ceramicforming:
� cold pressing, uniaxial pressing
� cold isostatic pressing
� aqueous injection moulding
� direct coagulation casting
� electrophoretic forming
� gelcasting
� hydrolysis assisted solidification
� pressure filtration
� explosive compaction
� lithography
New materials through a variety of forming methods
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Sintering
Sintering
Free sintering Pressure sintering:� High
� Ultra High
� ExtremalAtmosphere:
� air
� vaccum
� protective gases
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Sintering
Furnace• batch sintering
• continuous sintering
Methods of heating the furnace in the sintering process
indirect direct
• Gas, liquid and solid fuels resistive
heating by means of heating elements:
�Metallic (kanthal, superkanthal,
molybdenum, tungsten, platinum,
iridium, rhodium, chromium itp.)
�Non-metallic (silicon carbide,
molybdenum disulphide, lithium
chromate, zirconium oxide,
carbon, graphite, etc.)
• inductive
• microwave
• DC pulses
• Laser (Selective Laser Sintering)
• Electrons (Electron Bean Sintering)
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Sintering process can be divided into three categories:
� Solid Phase Sintering
� with Luiquid Phase Sintering
� Gas Phase Sintering
Sintering
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Sintering of ceramic or metallic
powders is a phenomenon that
occurs spontaneously at elevated
temperatures (below melting
point), as a result of the system's
desire to lower its surface energy,
which decreases as the grains are
joined
The goal of the sintering process is to convert highly porous compacted powder
into high strength bodies. The process is often accompanied by shrinkage
Sintering
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
The different physical phenomena used in sintering technologies
change thermodynamic conditions of sintering, which may affect the
crystalline form of the sintered phase and thereby change the properties
of the sintered material
Sintering
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
The development of new sintering equipment opens new avenues for new
material solutions :
� Microwave sintering
� Spark Plasma Sintering
� High and Ulta High pressure sintering:
• HIP - Hot Isostatic Pressing
• HP- Hot Pressing
• HP-HT– High Pressure High Temperature Sintering
� Selective Laser Sintering
� Electron Bean Sintering
Sintering
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Conventional and Microwave Sintering
Heating patterns in: a) conventional furnaces; b) microwave furnaces
A.R. Von Hippel, Dielectric Materials and Applications, Technplogy Press M.I.T.J. Wiley&Son Inc. Chapman and Hall Ltd. 1954
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Microwave Sintering
Many ceramics present poor microwave absorption characteristics. There are transparent
to microwaves, such as SiO2 or Al2O3
Temperature distribution in ceramic material heated by conventional heating, microwave
heating and microwave hybrid heating (Ts – surface temp.; TI – internal temp.
Sintering of ceramics – New Emerging Techniques; Romualdo R. Menezes, Pollyane M. Souto and Ruth H.G.A.
Kiminami Microwave Fast Sintering of Ceramic Materials; Edited by Arunachalam Lakshmanan, 2012 InTech
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Sintering process depend on:
� Microwave absorption characteristics (dieelectric loss factor (low-loss),
electrical conductivity)
� size and shape of green bodies
� Sintered materials distribution inside the furnace
M. Krage, (1981). Microwave sintering of ferrites. American Ceramic Society Bulletin, Vol. 60, pp. (1232-1234),
0002-7812
Ceramic materials will absorb microwave energy when they can be preheated to
suitable temperature using another heat source:
� Gas or electric furnace
� External susceptor material
Microwave hybrid heating MHH could result in samples with no significant
density gradient throughout the cross-section
Sintering of ceramics – New Emerging Techniques; Romualdo R. Menezes, Pollyane M. Souto and Ruth H.G.A.
Kiminami. Microwave Fast Sintering of Ceramic Materials; Edited by Arunachalam Lakshmanan, 2012 InTech
Microwave Sintering
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
SPS/ FAST method
FCT equipment, type HP D5 (Germany)
� sintering temperature up to 2400°C
� pulse duration 1 ms to 255 ms
� heating rate in the range from 5°C/min to 400°C/min
� pressing force from 3 kN to 50 kN
� vacuum, nitorgen, argon
For SPS apparatus the
processes are realized under
pressure up to 50 MPa (max.
500MPa for SPS Sumimoto
apparatus).
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
SPS/ FAST method
Pulsed direct current leading to cleaning and surface
activation of powders and generation of electric
discharge at neck region. Consequently, the
temperature raises very fast and densification is
completed within few minutes.
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Pulse heating in the SPS method
0.005 0.010 0.015 0.005 0.010 0.015
- 5 0 - 4 0 - 3 0 - 2 0 - 1 0 0 1 0 2 0 3 0 4 0 5 0
ton=15ms toff=5ms n=1 tp=0ms
ton=3ms toff=3ms n=1 tp=0ms
ton=2ms toff=1ms n=12 tp=6ms
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Current flow during heating by SPS depending on the conductivity of the sintered materials
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Comparison of duration in SPS/ Microwave/ Free Sintering methods
Heating rates and sintering duration in sintering processes of Al2O3 ceramics with SPS
method, microwave and free sintering methods
Piotr Putyra, Lucyna Jaworska, Marcin Podsiadło, Jolanta Laszkiewicz- Łukasik, Ceramic materials sintered using SPS
method. Materiały Kompozytowe (Composite Materials) 2015;nr 4:42–6 (in polish)
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Heating in Hot Pressing and SPS methods
HP vs SPS
Scheme for a) Hot Pressing
Suárez M, Fernández A, Menéndez JL, Torrecillas R, Kessel HU, Hennicke J, et al. Chapter 13: Challengesand Opportunities for Spark Plasma Sintering: A Key Technology for a New Generation of Materials. In: Ertuğ B, editor. Sintering Applications, InTech; 2013. doi:DOI: 10.5772/5370
b) Spark Plasma Sintering
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Temperature in HP and SPS methods
Temperature distribution (ΔT) and time (t*) needed to compensate
the temperature between set point (TA) and measured point (TI)
HP vs SPS
Kessel HU. Sintered Materials on the Way to Production by Means of Modern SPS Technologies. Ceramic Forum
International Berichte Der Deutschen Keramischen Gesellschaft 2009;10:145–52
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
� Piston units up to 4 GPa
� Belt type anvils 6-10 GPa
� Bridgman, Toroid and Paris-Edinburg type anvils 20 GPa
� Multianvils chamber 30-100 GPa
Types of HP-HT apparatus
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Mixture of powders
Bridgman type apparatus
High Pressure High Temperature sintering
Assembly for high
pressure-high
temperature sintering:
1 – pyrophyllite external
gasket;
2 – internal gasket;
3 – ceramic plate;
4 – molybdenium plate;
5 – sintered sample;
6, 7 – graphite heater;
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
HP-HT apparatus
Bridgman type anvils
HP-HT apparatus
High Pressure – High Temperature sintering
process:
�pressure: 7.8÷8.5±0.2 GPa
�temperature: 1800÷2200±50 °C
�duration of sintering process: below 1 min
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Stage I - pressing
Scheme of pressure distribution in the Bridgman type apparatus
σ0, τ– stress
HP-HT apparatus
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Stage II - sintering The example of the sintering curve
0 10 20 30 40 50 60 70 800
1
2
3
4
5
P
T [s]
P [
kW
]
0
1
2
3
4
5
R R
HP-HT apparatus
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Direct SLS/SLM of submicrometer Al2O3:� 800°C
� Density up 85%
� Grain size below 5μm
Multi step processes: � using the binder material to shape
ceramic;
� this binder material removed during
furnace treatment –„debinding”
J.Deckers, S.Meyers, B.Wijremblewski, , J.Vleugels, J.P. Kruth:
Direct selective laser sintering/melting of fine grained
alumina with a novel experimental setup, Mater. Sci. Tech.:
Special issue on 3D printing, 2014
EOS-EOSINT 250Xt ; Electrokorundum F120 (95-126 μm); 25-45%x250W;
layer thickness 0.1 mm; distance between lines 0.1 mmA.Stwora, G.Skrabalak (2016, IZTW Kraków)
Overview of Additive Manufacturing processes to shape ceramics
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Al2O3
Structure Unit cell parameters Density
[g/cm3]
Tempera
ture of
melting
point °C
a
[nm]
b
[nm]
c
[nm]
αAl2O3
Rhombohedral 0.476 0.476 1.299 3.99 2072
γAl2O3
Cubic 0.794 0.794 0.794 3.47
δAl2O3
Tetragonal 0.796 0.796 1.170 3.20
θAl2O3
Monoclinic 1.174 0.572 1.124 3.56
χAl2O3
Hexagonal 0.563 0.563 2.260 3.35
Advanced ceramics base on Al2O3
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Advanced ceramics base on Al2O3
Advanced ceramics based on Al2O3 exhibit
excellent properties such as high thermal
resistance, good chemical stability and moderate
to high mechanical strength. However, thefracture toughness of the materials is low.
The brittleness and poor damage tolerance have
so far limited their application
Composites:
Al2O3 + Mo
Al2O3 + SiC whiskers
Al2O3 + TiB2
Al2O3 + …
Al2O3 + cBN
www.ceramtec.com
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Al2O3 through various sintering techniques
Powder ID, Manufacturer Characteristics
Al2O3-α, Alcoa
+ sintering aid: 0.3 wt.% MgO
Al2O3-α > grade CT300-SG, 0.44 µm
Preparation:
� 30 h mixing in colloidal ball mill with presence of isopropyl alcohol
� For free sintering methods, polyethylene glycol was added, to aid in green bodies
preparation
Material:
The aim of presented work was to investigate the influence of various sintering
techniques on properties an microstructure of alumina.
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
HP-HT / HP SPS
Bridgman type apparatus
SPS Apparatus:
HP 5 FCT
Free sintering
HT16/18 Nabertherm
Furnace
Al2O3 through various sintering techniques
Free sinteringTemperature
range:
1620°C
Duration: 60 min
SPS sinteringTemperature range:
1550°C
Duration: 1 – 15 min
Pressure: 30 – 50MPa
Atmosphere: N2, Ar,
vacuum
HP-HT/HP SPS sintering:Temperature: 2000°C
Duration: 60s
Pressure: 4 GPa
Impulse lenght: 40 ms
Impulse interval: 20 ms
Microwavesintering:Temperature:
1620°C
Duration: 60 s
Microwave furnace
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
This work was supported by the European Commission under the FP7 Specific Programme 'Capacities' within the
framework of the SINTERCER project “Development of a sintering centre and know-how exchange for non-
equilibrium sintering methods of advanced ceramic composite materials” (REGPOT-2012-2013-1 EU FP7 Research
Potential, project no. 316232)
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Al2O3 through various sintering techniques
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Al2O3 through various sintering techniques
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
1620 °C, 60 min 1620 °C, 60 s
Free sintering
Al2O3 through various sintering techniques
Microwave sintering
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
50 MPa, 1550 °C, 15 min 50 MPa, 1550 °C, 15 min
SPS
Al2O3 through various sintering techniques
SPS with hBN insulation
Sintering method Mean grain size, d [µm]
Free sintering 2.57
Microwave sintering 2.86
SPS 1.41
SPS with hBN insulation 1.23
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Sintering
method
α-Al2O3
R-3m
θ-Al2O3
C2m
χ-Al2O3
P63/mmc
γ-Al2O3
Fd-3m
Al2O3
00-012-
0539
Initial powder ✔
Free sintering ✔ ✔
Microwave
sintering✔ ✔
✔
SPS ✔ ✔ ✔ ✔
SPS with hBN
Insulation✔ ✔
HPHT ✔ ✔ ✔ ✔
HP SPS ✔ ✔
Al2O3 through various sintering techniques
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Al2O3 through various sintering techniques
Sintering methodDensity
[g/cm3]
Young’s modulus
[GPa]Hardness HV1
KIC
[MPa*m1/2]
Free sintering 3.91 ± 0.01 383 ± 3 1868 ± 25 5.29 ± 0.31
Microwave sintering 3.87 ±0.01 387 ± 6 1600 ± 106 5.32 ± 0.42
SPS 3.95 ± 0.01 389 ± 4 1806 ± 34 6.80 ± 0.32
SPS with hBN insulation 3.95 ± 0.01 390 ± 5 1803 ± 37 7.17 ± 0.36
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Graphene properties
Very good conductor of heat and electricity - the measured thermal
conductivity is around 5300 W / mK (for comparison silver - 429 W / mK).
Young modulus around 1TPa
http://www.extremetech.comSource: Changgu Lee, Xiaoding Wei, Jeffrey W. Kysar, James Hone; Measurement of the
Elastic Properties and Intrinsic Strength of Monolayer Graphene ; Science 18 Jul 2008:
Vol. 321, Issue 5887, pp. 385-388.
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Purpose:The aim of our work was to confirm indicated by SEM and TEM microstructural
analysis that the applied pressure during the sintering process (SPS) leads to the
orientation of the phase and in consequence to anisotropy of the
alumina/graphene composite
Starting powders:
Powder ID, Manufacturer Characteristics
Al2O3-α, Almatis
+ sintering aids: 0.3 wt.%MgO
Al2O3-α > 99.8%, grade A16SG, 0.3-0.6 µm
Graphene Platelets, Cheap Tubes, USA grade GPLs(4), average flake thickness <4 nm,
<4 monolayers, average particle (lateral) size 1-
2 µm
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
SEM magnifications: 1 000x - 50 000x
GPLs(4): thickness 4 nm (a few monolayers)/ lateral size ~1-2 µm
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
The mixtures of alumina with addition of 0.15 wt% and 2 wt.% GPLSs was
prepared using planetary mill.
• Planetary mill Pulverisette 6 (Fritsch)
• ZrO2 grinding bowl 250ml and grinding balls 5
mm in diameter
• rotational speed: 200
• milling duration: 8 h
• isopropanol
• drying and sieving
Mixtures preparation
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Spark Plasma Sintering – process parameters
• Pressure: 35 MPa
• Temperature: 1550 °C
• Vacuum
• duration: 10 minutes
The chamber Die assemble
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Microstructure of Al2O3 base ceramics with addition 2 wt.% of GPLs(4),
homogenised for 8h in planetary mill;
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Microstructure of Al2O3 base ceramics with addition 2 wt.% of GPLs(4),
homogenised for 8h in planetary mill; TEM, magnification 180 000x
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Properties
Material
Al2O3 –
initial
Al2O3 +
0.15% GPLs
(4)
Al2O3 + 2% GPLs (4)
⊥
Al2O3 + 2%GPLs
(4)
II
Density
[g/cm3]
3.90 ±0.01
(99%)
3.94 ±0.01
(99%)
3.83 ±0.01
(98%)--
Young modulus
[Gpa]
381 ±8
(98%)
381 ±8
(98%)
307 ±6
(75%)
351 ±3
(85%)
Vickers hardness HV1
[GPa]17.7 ±0.2 15.8 ±0.2 15.5±0.2 16.8±3
Fracture toughness KIc
[MPa∙m1/2]5.6 ±0.2 5.4 ±0.3 5.1 ±0.2 5.2 ±0.2
J. Morgiel, P. Klimczyk, Ł. Major, L. Jaworska, Ł. Maj, T. Cygan, A. Olszyna, TEM investigations of wear mechanism of
Al2O3 and Si3N4 compacts with GLPs additions; Ceramics International, Volume 43, Issue 11, 1 August 2017,
Pages 8334-8342
Al2O3/graphene � anisotropy of properties
Physical – mechanical properties
The following test conditions were
established:
Al2O3 ball diameter: 2.0 mm,
applied load: 4 N,
sliding speed: 0.1 m/s,
diameter of the sliding circle: 3 mm,
the sliding distance: 1 000 m,
duration of the test: 10 000 s,
temperatures: RT
Typical ball-on-disc
setup where
• Fn is the normal force
applied on the ball;
• Ft is the friction force
Al2O3/graphene � tribological tests
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Friction coefficient and specific wear rate for the sample containing 2 wt.% of GPLs(4)
for tests carried out on the surface parallel and perpendicular to the pressing direction.
J. Morgiel, P. Klimczyk, Ł. Major, L. Jaworska, Ł. Maj, T. Cygan, A. Olszyna, TEM investigations of wear mechanism of
Al2O3 and Si3N4 compacts with GLPs additions; Ceramics International, Volume 43, Issue 11, 1 August 2017,
Pages 8334-8342
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Conclusions
� Despite observed orientation of the graphene platelets, hardness and fracture
toughness measurement values were not strongly dependant on the
measurement direction in relation to the pressing axis
� Mean coefficient of friction for both surface parallel and perpendicular to the
pressing direction was about 0.7
� Specific wear rate of disc was notably smaller in case of surface perpendicular to
the pressing axis
Al2O3/graphene � anisotropy of properties
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Alumina based composites with low electrical resistivity
Drilling using EDM technique
High hardness ceramic materials with low electrical resitivity (< 10 Ω) to forming using
EDM technique
Cutting using EDM technique
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Materials
Free sintering
parameters
Apparent
Density
Young
ModulusHardness
Electrical
Resistance
temperature [°C]
duration [min][g/cm3] [GPa] HV1 [Ω]
Al2O3 1700 / 60 3.94 390 1700 5·1014
Al2O3+20%Mo 1700 / 60 4.80 350 1442 > 10·106
Al2O3+30%Mo 1700 / 60 5.13 349 1474 4.4
Al2O3+20%Mo 1800 / 60 4.84 364 1431 > 10·106
Al2O3+30%Mo 1800 / 60 5.18 358 1438 3.3
Alumina based composites with low electrical resistivity
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Materials
SPS sintering
parameters
Apparent
Density
Young
ModulusHardness
Electrical
Resistance
temperature [°C]
duration [min][g/cm3] [GPa] HV1 [Ω]
Al2O3
+30%Ti(C,N)1650 / 1 4.29 401 2042 1.32·10-1
Al2O3-Ti(C,N)
+5%TiB2
1650 / 1 4.29 407 1966 8.12·10-2
Al2O3-Ti(C,N)
+10%TiB2
1650 / 1 4.29 392 1996 4.28·10-2
Al2O3-Ti(C,N)
+30%TiB2
1650 / 1 4.27 402 2106 1.35·10-2
Al2O3-Ti(C,N)
+50%TiB2
1650 / 1 4.19 414 2226 1.92∙10-2
Alumina based composites with low electrical resistivity
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
EDM drilling of
Al2O3-Ti(C,N)-TiB2
EDM cutting of
Al2O3-Ti(C,N)-TiB2
P. Putyra, L. Jaworska, M.Podsiadło, J. Laszkiewicz-Łukasik, T.Krzywda, The ceramic materials to forming by EDM
method, The Korean Powder Metallurgy Institute. 2016 ISNNM-2016 The 14th International Symposium on Novel and
Nano Materials, July 3-8 2016
Alumina based composites with low electrical resistivity
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
it is possible to conclude that the presence of MoO3 phase and a very high
tool life of Al2O3–15 wt.% Mo composite confirms the thesis of good
lubricating properties of MoO3 phase in dry machining conditions.
Al2O3–15 wt.% Mo - Hot Pressing 20MPa, 1350°C, 60 min, atm. argon
K. Broniszewski, J. Woźniak, K. Czechowski, L. Jaworska, A. Olszyna, Al2O3–Mo cutting tools for machining hardened
stainless steel, Wear, Vol.303, Iss. 1-2, 15 June 2013, Pages 87-91
MoO3 structure schemeModel of cutting tool thermal oxidation during machining
Alumina based composites with low electrical resistivity
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
� Additions of Mo, Ti(C,N), and TiB2 have significant influence on decreasing
electrical resistance and mechanical properties are not changing
� For all kinds presented materials is possible to use EDM technique
Conclusions
Alumina based composites with low electrical resistivity
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
The aim of our work is to obtain Al2O3-cBN composites with high
hardness and fracture toughness which can be easily produced by
SPS (spark plasma sintering) method.
Potential applications: cutting tools or different small wear parts.
High and low pressure sintering of Al2O3-cBN compositescomparison of two methods:
• HPHT: 7.7 GPa
• SPS: 35 – 75 MPa
Al2O3-cBN composites by HPHT and SPS
P. Klimczyk , M.E. Cura , A.M. Vlaicu , I. Mercioniu , P. Wyżga, L. Jaworska , S-P. Hannula
Al2O3 – cBN composites sintered by SPS and HPHT methods. Journal of the European Ceramic Society 2016 , 36, 7 ,
1783-1789
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Al2O3 – cBN composites sintered with HPHT and SPS methods
Young's modulus
HPHT 7.5 GPa, 1 min
SPS 75 MPa, 4 min
SPS 35 MPa, 4 min
Density
HPHT 7,5 GPa, 1 min
SPS 75 MPa, 4 min
SPS 35 MPa, 4 min
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
7.5 GPa, 1170 °C, 1 min 7.5 GPa, 1880 °C, 1 min
HPHT
Al2O3 – cBN composites sintered with HPHT and SPS methods
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
75 MPa, 1300 °C, 4 min 35 MPa, 1300 °C, 4 min
SPS
Al2O3 – cBN composites sintered with HPHT and SPS methods
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Microstructure and phase analysis
Sintering method
(parameters)
Al2O3 alpha c-BN h-BN Al5BO9
HPHT
(7.5GPa, 1174 °C, 1 min)69.4 % 30.5 % - -
HPHT
(7.5GPa, 1883 °C, 1 min)69.2 % 29.2 % 1.3 % -
SPS
(75MPa, 1300 °C, 4 min)68.81 % 28.47 % - 2.72 %
SPS
(35MPa, 1300 °C, 4 min)68.71 % 27.80 % 1.04 % 2.45%
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Physical and mechanical properties
Sintering method
(parameters)
Density
(relative density)
Young’s
Modulus
(relative Young’s
modulus)
Vickers
hardness
HV1
Fracture
toughness KIC
g/cm3
(%)
GPa
(%)GPa MPa·m1/2
HPHT
(7.5GPa, 1170 °C, 1 min)
3.82 ±0.01
(>99%)
457 ±8
(84%)21.8 ±1.6 -
HPHT
(7.5GPa, 1880 °C, 1 min)
3.78 ±0.01
(98%)
453 ±8
(83%)16.8 ±0.9 8.2 ±0.5
SPS
(75MPa, 1300 °C, 4 min)
3.69 ±0.01
(96%)
433 ±5
(79%)18.6 ±0.7 6.5 ±0.2
SPS
(35MPa, 1300 °C, 4 min)
3.51 ±0.01
(91%)
382 ±6
(70%)16.1 ±1.2 5.9 ±0.5
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Tribology
Specific wear rate of Al2O3 + 30 vol.% cBN material (disc) obtained by HPHT and SPS
method as the result of sliding contact with the Al2O3 ball (diameter 3.2 mm) under load
of 10N during Ball-On-Disc test.
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Conclusions
� Sintering temperature for Al2O3 – cBN composites for HPHT method
(1170 °C) is about 100 °C lower than for SPS (1300 °C)
� The microstructures of the investigated samples are homogeneous,
with the components uniformly distributed in the volume of the
composite.
� The composites obtained by SPS have slightly lower density and
Young’s modulus than those obtained by HPHT but their fracture
toughness is still better than for pure alumina.
� The best wear resistance have samples sintered by SPS at 75 MPa.
� There was no observed of significant hBN formation during SPS
processes (only ~1% of hBN at 35 MPa); SPS is a promisingalternative to expensive HPHT in the preparation of CMC’scontaining metastable cBN phase
Al2O3 – cBN composites sintered with HPHT and SPS methods
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Conclusion
Choosing the method of sintering is determined by the
possibilities and limitations of individual methods but above all
there is the economic calculation
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
CRM-EXTREME
www.crm-extreme.eu
http://www.cost.eu/COST_Actions/ca/CA15102
Acknowledgments
I thank my colleagues from the Institute
of the Advanced Manufacturing Technology for their help
in preparing this presentation
E-MRS Fall Meeting
18th - 21th September 2017
Warsaw, Poland
Thank you for your attention