1. 1
FABRICATION OF SiC/SiCf COMPOSITE
BY VACUUM INFILTRATION AND
HOT PRESSING
Parlindungan Yonathan1, Jong-Hyun Lee1, Dang-Hyok Yoon1,
Weon-Ju Kim2 and Ji-Yeon Park2
1School of Materials Science and Engineering, Yeungnam University
2Nuclear Materials Research Division, KAERI, Korea
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Presentation Outline
Background
SiC/SiCff Experiment advantages
SiC/SiC applications and
Fusion reactors applications and issues
Conclusion
Main Goal
Materials
Process
Composition
Design
Result
4. 4
SiC/SiCf Advantages
High specific strength
Good high-temperature properties
Good fracture resistance
Good thermal conductivity
Corrosion and wear resistance
Low induced radioactivity under nuclear
environments
6. 6
Fusion Reactors
He bubbles
First Wall
Be, Be-alloy
W, W-alloy
SiC/SiCf,C/C
Fusion reactor blanket concept:
• TAURO, European Union (SiC/SiCf)
• ARIES-AT, US (SiC/SiCf)
• DREAM, Japan (Be-Li2O-SiC)
ARIES-AT vertical cross-section
*Fusion technology institute, University Wisconsin
7. Permeability issue in SiC/SiCf 7
0.86Å
Bombardment of high Point defect behavior in
energetic neutrons in to ceramics
composite surface
He and H atoms will move to a
Bubbles formation on the porous site, vacancy cluster,
surface or blistering and grain boundary to start
causing delamination issue
* J.H Kim, Y.D Kwon, Parlindungan Yonathan, I. Hidayat, “The energetic of He and H atoms in the irradiated β-SiC: ab
initio approach”
8. 8
Main Goal
To achieve a high density SiC/SiCf composite by
maximizing SiC slurry infiltration into SiC woven fiber
and finally to attain high structural strength composite
material
Process development high density composite material:
Milling process
Infiltration method
Slurry composition
Tape casting
Evaluation of material performance
Material characteristics and morphology
Mechanical properties
10. 10
SiC powder
β-SiC, NanoAmor β-SiC, Marketech
Average particle size: 52nm(NanoAmor),
30nm(Marketech)
Fine & spherical β-SiC
BET: 80 m2/g (NanoAmor), 109 m2/g (Marketech)
Surface is covered with SiO2 layer thinner than 1.7nm
2nm
11. 11
SiC Woven fiber
(220nm)
Top view Cross-section view Pyrolitic carbon-coated fiber
TyrannoTM-SA Grade-3 Fiber
Ube Industries, Ltd., Tokyo, Japan 2D woven fiber
Properties Tyranno-SA Grade-3
Atomic composition (C/Si) 1.08, Al 0.005
PyC coated by KAERI
Diameter (mm) 7.5 PyC coated design was
Number of
filaments/yarn
1600 based on CVI-SiC/SiCf
Tensile strength (MPa) 2500 composite process
Mass density (g/cm3) 3.1
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Sintering Additives
Alumina Oxide (Al2O3) Magnesium Oxide (MgO) Yttrium (III) Oxide (Y2O3)
Sintering additives facilitate the densification of
SiC due to its highly covalent bond structure
Al2O3/Y2O3/MgO = (0.64/0.26/0.1) wt%*
Liquid phase assisted sintering
* KY Lim, DH Jang, YW Kim, JY Park, DS Park,quot; Effect of the processing parameters on the densification and strength
of 2D SiC fiber-SiC matrix composites fabricated by slurry infiltration and stacking process
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Process focus
Milling (dispersion)
Solid volume fraction in green body
Infiltration
Rate of infiltration and densification
Sinterability (pressure, temperature)
Effective infiltration
Controllable infiltration
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Ball milling vs. High Energy
Milling
@
Ball mill High energy mill
The most conventional Recently introduced
mechanical milling (MiniCer, Netzsch)
2–200 mm spherical or 0.01 – 0.8 mm ZrO2 beads
cylindrical balls
Rotation up to 4200rpm
Rotation under 200 rpm
Very effective in milling
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Why HEM
Milling time (min) Herring’s scalling laws:
0 20 40 60 80 100 120
n
15000
t1 ⎛ r1 ⎞
High energy milling
=⎜ ⎟
⎜r ⎟
⎝ 2 ⎠
12000
t2
Viscosity(mPa.s)
9000 At constant temp
Ball milling Rumpf’s Equation:
6000
1.1φ A
3000 σ= .
0
1 − φ 12rl 2
0 20 40 60 80 100 120
Milling time (hr)
All proposed mechanisms of sintering and densification of ceramic powder
compacts agree that the particle size is one of the most important parameters
in the rate of progress of these processes.
* Nono Darsono a, Dang-Hyok Yoon a,*, Jaemyung Kim b, “Milling and dispersion of multi-walled
carbon nanotubes in texanol”
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Vacuum Infiltration
Enhance the infiltration by vacuum
absorption force
Enhance the composite density in
fiber
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Vacuum Infiltration
The slurry is infiltrated as the
vacuum pressure
Vacuum release
Vacuum on progressively released to
return to surrounding pressure,
thereby causing the slurry to
be forced through the fiber
pores.
Advantages:
SiC Slurry Using vacuum force to help
infiltration process
SiC Fiber Infiltration can be controlled by
altering the vacuum pressure
and release of vacuum time.
Vacuum pressure 0.1Pa
Pumping speed 120L/min
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Vacuum Infiltrated fiber - SEM
Top view
Cross-section view
Normal infiltration (dipping) Vacuum infiltration
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Composite structure
Composite formed by stacking
SiC green tape
the SiC green sheet and the
Infiltrated SiC infiltrated SiC fibers
fiber with SiC
slurry Binder burn-out at 4000C for 2-
hours at 1oC/min
Hot pressed at 1750oC, 20MPa,
Hot pressing 3-hours
5cm SiC infiltrated SiC infiltrated
fiber (NanoAmor) fiber
20 infiltrated fibers and (Marketech)
tapes
SiC/SiCf composite [0o/45o] Green tape Green tape
62-72% fiber volume fraction (NanoAmor) (Marketech)
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Effect of green tape
Binder solution
HEM (High energy milling)
vacuum infiltration & stack with SiC
Tapes
Drying Cryo-fracture
Binder burn-out SEM
Tape casting
Sintering (Hot Factors:
Pressing)
Slurry composition
Dispersion
Bending test Density SEM Zeta potential
(4-point) (Archimedes)
Viscosity
DISPERSION STABILITY AND ITS EFFECT ON TAPE CASTING OF SOLVENT-BASED SiC SLURRY
Jong-Hyun Lee, Parlindungan Yonathan, Dang-Hyok Yoon, Weon-Ju Kim* and Ji-Yeon Park* (Yeungnam University,
Korea, * KAERI, Daejeon, Korea)
30. Sintered SiC/SiCf 30
Relative density & Flexural strength of SiC/SiC f
100 300
Flexural Strength (MPa)
Relative Density (%)
200
80 Sample 1 (Nano-tape)
100
60
Nano-tape Nano Marketech
Powder type Sample 2 (Nano)
Vacuum
Other Hot
infiltration &
pressing CVI-PiP
Hot pressing
reported value
Density (g/cm3) 3.161 2.9-3.0 2.5-2.8
Percent density (%) 98.78% 90-95% 80-90%
Sample 3 (Mark-tape)
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XRD result
XRD result of SiC/SiC f composite The phase
structure were
Marketech
Sample 3 changed for
both nano
powder,
Intensity (a.u.)
Nano however phase
Sample 2 change were
not observed
for marketech
β− SiC phase Nanotape powder
α− SiC phase Sample 1
20 30 40 50 60 70 80
2θ
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Conclusion
• High density of SiC/SiCf was achieved at 3.161g/cm3
(98.78%) by vacuum infiltration and hot pressing process.
• Flexural strength of 230MPa was achieved with a brittle
fracture mode showing very little fiber pull out.
• Phase changed was observed after hot pressing at 1750oC-
20MPa-3hours, showing both alpha and beta-SiC phase in
the composite.
• SiC tape improved the sintered density and strength in the
SiC/SiCf composite.
• Slurry formulation including sintering additives plays an
important role in vacuum infiltration and hot pressing process.
• More intensive experiment on SiC/SiCf interface to improve
the composite strength.
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Acknowledgement
This project is financial supports by:
The Ministry of Knowledge Economy through a Materials &
Components Technology R&D Program
Highly appreciated
