Lili Nadaraia, Nikoloz Jalabadze,
Levan Khundadze, Levan
Lortkipanidze and Givi Sharashenidze
Georgian Technical University,
Republic Center for Structure Researches (RCSR)
nadaraia@gtu.ge
Ultra-High Temperature Ceramics
Borides
Carbides
Compositions
TiC
TiB2-TiC,
B4C-SiC,
Ti3SiC2
TiB2
ZrB2
HfB2
B4C
SiC
Application
Armor
low density
high hardness
Nozzles
Abrasives
 Abrasion resistance
Nuclear
applications
as neutron
radiation
absorbent
UHTC
 wear resistance
Refractory
applications
 high melting
poin
 thermal
stability
Manufacturing methods of UHTC
Methods producing the
Powder
Methods producing the
Dense bodies
• reaction of elemental boron
and carbon powder between
reagents
• carbothermal synthesis,
• carbothermal vapor–liquid–
solid growth mechanism
• self-propagating hightemperature synthesis (SHS) =
Combustion Synthesis (CS),
• arc melt process,
• etc…
• hot press,
• hot isostatic pressing
(HIP),
• Cold compaction and high
temp. sintering
• pressureless sintering,
• self-propagating hightemperature synthesis
(SHS) under the pressure,
• Spark Plasma Sintering,
• etc…..
Advantages and disadvantages
of spark plasma sintering
Advantages of spark plasma sintering:
Fast sintering process;
Uniform sintering;
Low grain growth (nano-grain materials may be prepared);
Compaction and sintering stages are combined in one operation;
Binders are not necessary;
Better purification and activation of the powder particles surfaces;
Different materials (Metals, Ceramics, composites) may be processed;
High energy efficiency;
Easy operation.
Disadvantages of spark plasma sintering:
Only simple symmetrical shapes may be prepared;
Expensive pulsed DC generator is required.
Expensive
SPS device
Fig.1. Scheme of the SPS the process of sintering
– PDC - pulsed DC, GD - graphite die, S – powder
sample, P – pressure loading, EC- electric current,
s – spark, sp – spark plasma and p- powder
particles.
SPS mechanism by SPS SYNTEX INC Company;
(a) I- Flow direction of electrons during DC current,
(b) I- Flow directions of electrons during AC
current.
DC current shapes
Pulse DC current Shape in the developed device:
a- at the frequency of 400 Hz, b- during different
frequencies (T), different duration pulses (t) and
different duration pauses (T-t);
Current Shapes to be used after
retrofitting the SPS device: during
different frequencies (T), different
duration pulses (t) and different
duration pauses (T-t);
SPS Device
Press molds for synthesize nanopowder (a) and
sintering dense bodies (b) of composite
materials 1-upper plug, 2-lower plug, 3-Matrix.
Self-propagating high-temperature synthesis (SHS), (combustion
synthesis CS)
Poly SHS
A. G. Merzhanov. 2006, Advances in
Science and Technology, 45, 36- 44.
Sintering process a: Self-Propagating HighTemperature Synthesis (SHS), b: SPS
accompanied with poly SHS.
Borides
B4C
B4C
2TiO2
2HfO2
3C
3C
B4C
2ZrO2
2HfB2+4CO
2TiB2+4CO
3C
HfB2
TiB2
2ZrB2+4CO
ZrB2
Titanium Diboride
X-Ray and SEM images of Titanium Diborides
a- TiB2 powder synthesis at 10000C 1h,
b- sintered via SPS at 16000C ;
C- SEM image of sintered via SPS at 16000C
TiB2
Zirconium Diborides
ZrB2
X-Ray and SEM images of
Zirconium Diborides
a- ZrB2 powder synthesis at
10000C 1h,
b- sintered via SPS at
16000C ;
C- sintered via SPS at
17000C
SEM images of Zirconium
Diborides sintered via SPS
at 17000C
Hafnium Diborides
HfB2
X-Ray and SEM images of Hafnium
Diborides sintered via SPS at
18000C ;
Carbides
Si
C
4B
Ti
C
C
SiC
B4C
TiC
Carbides
TiC
SiC
X-Ray images of Titanium Carbide
sintered via SPS at 14000C -3 min;
X-Ray images of Silicium Carbide
sintered via SPS at 18000C -1 min;
Boron Carbide
B4C
a- XRD pattern of B 4C powder (SPS
14000C-3 min)
b- SEM image of B4C bulk material (SPS
17000C-10min)
A-XRD patterns of B 4C powder materials
obtained by standard (a), SPS methods (b) ;
B- SEM image of nanopowder B 4C
obtained by SPS method (1400 0C-3min).
Composition
Si
4B
2C
B4C - SiC
SPS sintered B4C – SiC (17000C-5min):
a-X-ray diffraction pattern; c- SEM image B4C
– SiC Sintered via SPS
b- SEM image of B4C – SiC powder produce
via SPS.
Composition
Si
3Ti
2C
Ti3SiC2
X –Ray of Ti3SiC2 composition of sintered via SPS at 14500C
Composition
B4C
2TiO2
3C
TiB2 - TiC
Vickers hardness
29.5 Gpa
TiB2
TiC
X –Ray and SEM images of TiB2 - TiC composition of sintered via SPS at 14500C
SPS OPERATING MODES WITH
RELATIVELY DENSITY
SPS
TiB2
SPSSPSTiB2B4C-SiC TiC
9.2/2060 10/2700
9/2700
9.5/2300 10/2700 9/2700
1700
1800
1600
1700
1700
1450
5
10
5
5
5
5
6
0
20
20
25
20
30
30
-
94
85
92
95
98
97
SPSSample#
SPSB4C
Regime
BC
powder 4
SPSCurrent
(V/A)
Temp.
9/1370
(0C) 1600
Holding
Time (min)
Pressure
MPa
Density
(% of
theoretical)
SPS
HfB2
SPS
Ti3SiC2
Shapes of materials
sintered via SPS
Ballistic Testing
Test is conducting according
Standards of National Institute
of Justice (NIJ) (type-IV)
Additional energy is absorbed by each successive
layer of material in the ballistic panel.
http://www.bodyarmornews.com/
¤
Size of the plate -120x120mm;
¤
Size of the plate fragments
Bullet direction
¤
Hard Blend
(B4C, SiC, B4C-TiB2, B4C-SiC )
¤
Backing material
Plastic (Ti-6Al-4V)/textile
¤
60x60mm; Weight - 50-100g.
The plate presented a package armored with
ballistic textile (Kevlar, tvarin, denima); Weight
of the package was 0,6 – 0,8 kg;
Fire tests were provided by shooting from the
Mosin’s Rifle;
• Bullets - armor-piercing
• Bullet Mass – 10.8±0,1;
• Bullet speed - 869±10 m/sec.
Standard shooting method, distance - 10m
towards a plasticine target.
Ballistic testing
120mm
BFS
NIJ requirements - Max Back face signature (BFS) depth is 44mm
40mm
Conclusion
 There was developed new technology for manufacturing of nanocrystalline
composite materials.
 Poly SHS process were detect during SPS and were use for UHTC materials
fabrication
 Diborides of transaction metals Ti, Zr, Hf, were produced
 Nanocrystalline Powders of carbides of metals Ti, Si, and B were obtain after Poly
SHS process
 Effective composition materials TiB2 - TiC, Ti3SiC2, B4C - SiC were developed.
 Ballistic testing gives promising results and further effort will be directed to
improve the characteristics.
 Modernization of SPS device is undergoing process (replacing of pulse DC current
unit with pulse AC current unit).
 Further work will be directed to detect impacte of DC current at the sintering
process and at the materials properties.
ACKNOWLEDGEMENT
The part of research described in this presentation was
made possible in scope of projects funded by Shota
Rustaveli National Science Foundation.
Project # 12/34 Presidential Grants for Young Scientists.
nadaraia@gtu.ge