1. Silicon Carbide: Manufacturing Processes and Material Properties
B. C. Bigelow, UM Physics
3/24/05
3/24/05
Bruce C. Bigelow -- UM Physics

2. Silicon Carbide for SNAP
Motivations:
Silicon Carbide has extreme material properties
Very high thermal conductivity
Very low thermal expansion – close match to Si
Very high specific stiffness (E/r)
Fabrication processes have matured
Process-tunable material properties
Complex geometries, assemblies
Substantial space heritage exists
Space science applications
Military applications
Structures and reflecting optics
3/24/05
Bruce C. Bigelow -- UM Physics

3. Silicon Carbide for SNAP
This talk:
Brief history
Manufacturing processes
Commercial sources
Material properties
Spacecraft heritage
Current applications
Conclusions
3/24/05
Bruce C. Bigelow -- UM Physics

4. Silicon Carbide for SNAP
History:
Accidentally discovered by Edward G. Acheson (assistant to Thomas Edison) in 1890, while trying to synthesize diamond.
First synthesis method - “Acheson Process” – SiC created intentionally by passing current through a mixture of clay and carbon
“Natural” SiC found only in meteorites, in very small quantities
3/24/05
Bruce C. Bigelow -- UM Physics

5. Silicon Carbide for SNAP
SiC Raw Material Production:
Acheson Process – for producing powders
Pyrolysis – for producing fibers
Reactions of silicon and carbon – for producing whiskers
3/24/05
Bruce C. Bigelow -- UM Physics

6. SiC Production Processes
Chemical Vapor Deposition (CVD); 99+% theoretical density, single phase
Chemical Vapor Composite (CVC); CVD with particulate injection (Trex)
Chemical Vapor Infiltration (CVI); graphite or carbon conversion / infiltration; graphite “greenbody”, may be reinforced with carbon or other fibers (C/SiC), multi-phase final material, porosity varies with process, also called Ceramic Matrix Composite (CMC)
Sintering; trace amounts of impurities and second phase result from sintering additives, few percent porosity
Slip Casting; similar to sintering, with liquid mold-filling additives
Reaction Bonding; two phase mixture of SiC and Si, percentages and porosity vary with process
Hot Isostatic Pressing (HIP); near-theoretical density, may have second phase or impurities from hot-pressing additives, can be very low porosity (inert gas compaction)
Hot Pressing; mechanical pressure compaction with electric current heating
3/24/05
Bruce C. Bigelow -- UM Physics

7. Selected Sources for SiC
BOOSTEC (Tarbes, France)
Cercom (Vista, CA)
Ceradyn (Costa Mesa, CA)
Coorstek (Golden, CO)
GE Power System Composites (Newark, DE)
IBCOL (Munich, Germany)
Kyocera Advanced Materials (Vancouver, WA)
Poco Graphite (Decatur, TX)
SSG Precision Optronics (Wilmington, MA) – no mat props.
Trex Enterprises (Lihue, HI)
Rohm & Haas (Woburn, MA)
Saint Gobain / Carborundum (Niagara Falls, NY)
3/24/05
Bruce C. Bigelow -- UM Physics

8. SiC fabrication - IBCOL
3/24/05
Bruce C. Bigelow -- UM Physics

9. SiC fabrication - Boostec
Picture of the Week
SiC fabrication - Boostec
3/24/05
Bruce C. Bigelow -- UM Physics

10. R. Temp SiC Material Properties
Manuf.
Process E,
GPa
Fl. Str,
Mpa
Kic,
MPa*m0.5
Density,
kg/m^3
Poisson
ratio
CTE,
ppm/C K,
W/m*K
Boostec
sintered
420
450
3.5
>3100
0.16
4.0
180
Ceradyne
CVD
440
375
3.1
3200
0.17
4.5
200 HP
634
4.3
4.8
115
430
400
120
Cercom
CVI
460
570
4.4
130
Coorstek
462
468
3210
0.21
4.6 RB
4-5
3100
0.20
125
410
480
3150
150
GE Cesic
C/SiC
197
2650
2.1
IBCOL
235
175
2.6
135
Kyocera
539
5.6 63
Poco
218
147
2.3
2530
1.2
170
Rohm-Haas
466
461
3.3
2.2
300
St.Gobain
240
0.14
Trex
380
3.4
3/24/05
Bruce C. Bigelow -- UM Physics

11. SiC Mat. Prop. Comparisons
Manuf.
Process E,
GPa
Fl. Str,
Mpa
Kic,
Mpa-m-0.5
Density,
kg/m^3
Poisson
ratio
CTE,
ppm/C K,
W/m*K
Ceradyne
CVD
440
375
3.1
3200
0.17
4.5
200
Coorstek
462
468
3.5
3210
0.21
4.6
115
Rohm-Haas
466
461
3.3
2.2
300
Trex
380
3.4
GE Cesic
C/SiC
197
120
4.62
2650
2.1
125
IBCOL
235
175
2.6
135
AlN
330
290
3260
0.24
170
Alum 7075-T6 72 50 24
2790
0.33
23.4
160
TZM
Arc cast
325
860
6-30
10160
0.32
4.9
Molybdenum
Stress rel.
415
10220
5.35
138
304 St. Stl.
193
500
346
8030
0.29
16.2 16
3/24/05
Bruce C. Bigelow -- UM Physics

12. Bruce C. Bigelow -- UM Physics
SiC Space Heritage
Heritage missions:
NASA EO-1 ALI – SiC mirrors
ESA ROCSAT2 – SiC optical bench
ESA ROSETTA – SiC optical bench
3/24/05
Bruce C. Bigelow -- UM Physics

13. Bruce C. Bigelow -- UM Physics
SiC Space Heritage – EO1
3/24/05
Bruce C. Bigelow -- UM Physics

14. SiC Space Heritage – Rosetta
Rosetta – SiC optics and optical bench
3/24/05
Bruce C. Bigelow -- UM Physics

15. SiC Space Heritage - ESA
IBCOL EADS/ESA verification structure
3/24/05
Bruce C. Bigelow -- UM Physics

16. SiC Space Applications - Hershel
3.5m SiC primary mirror
3/24/05
Bruce C. Bigelow -- UM Physics

17. SiC Space Applications - Hershel
Hershel SiC secondary mirror support structure
3/24/05
Bruce C. Bigelow -- UM Physics

18. ESA - GAIA GAIA optical layout – 2 fields simultaneously 3/24/05
Bruce C. Bigelow -- UM Physics

19. Bruce C. Bigelow -- UM Physics
ESA - GAIA
GAIA focal plane mosaic – 10 x 18 = 180 CCDs 4500 x 1966 px/CCD, 1.5 Gpx
3/24/05
Bruce C. Bigelow -- UM Physics

20. SiC Space Applications - GAIA
Picture of the Week
SiC Space Applications - GAIA
GAIA SiC primary mirror demonstrator - 1.4m x 0.5m
3/24/05
Bruce C. Bigelow -- UM Physics

21. SiC Space Applications - GAIA
Picture of the Week
SiC Space Applications - GAIA
GAIA SiC stability verification optical bench
3/24/05
Bruce C. Bigelow -- UM Physics

22. SiC Space Applications - GAIA
Picture of the Week
SiC Space Applications - GAIA
GAIA focal plane demonstrator model (Boostec):
770mm by 580mm by 36mm, with a mass of about 8kg.
3/24/05
Bruce C. Bigelow -- UM Physics

23. SiC Space Applications - GAIA
Picture of the Week
SiC Space Applications - GAIA
GAIA focal plane - sintered SiC – detector mounting detail
3/24/05
Bruce C. Bigelow -- UM Physics

24. Silicon Carbide for SNAP
Conclusions:
There are many commercial sources for SiC
SiC material production and fabrication methods are well developed
SiC and C/SiC demonstrate extremely high performance material properties
Space heritage for SiC has been established
NASA and ESA are using of SiC in current programs
SiC is a real option for SNAP, both for optics and structures
3/24/05
Bruce C. Bigelow -- UM Physics