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

13/24/05 Bruce C. Bigelow -- UM Physics

Silicon Carbide:Silicon Carbide:Manufacturing Processes and Manufacturing Processes and

Material PropertiesMaterial Properties

B. C. Bigelow, UM Physics

3/24/05

23/24/05 Bruce C. Bigelow -- UM Physics

Silicon Carbide for SNAPSilicon Carbide for SNAP

Motivations:

1. Silicon Carbide has extreme material properties• Very high thermal conductivity

• Very low thermal expansion – close match to Si

• Very high specific stiffness (E/r)

2. Fabrication processes have matured• Process-tunable material properties

• Complex geometries, assemblies

3. Substantial space heritage exists• Space science applications

• Military applications

• Structures and reflecting optics

33/24/05 Bruce C. Bigelow -- UM Physics

Silicon Carbide for SNAPSilicon Carbide for SNAP

This talk:

1. Brief history

2. Manufacturing processes

3. Commercial sources

4. Material properties

5. Spacecraft heritage

6. Current applications

7. Conclusions

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Silicon Carbide for SNAPSilicon 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

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Silicon Carbide for SNAPSilicon Carbide for SNAP

SiC Raw Material Production:

1. Acheson Process – for producing powders

2. Pyrolysis – for producing fibers

3. Reactions of silicon and carbon – for producing whiskers

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SiC Production ProcessesSiC Production Processes

1. Chemical Vapor Deposition (CVD); 99+% theoretical density, single phase

2. Chemical Vapor Composite (CVC); CVD with particulate injection (Trex)

3. 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)

4. Sintering; trace amounts of impurities and second phase result from sintering additives, few percent porosity

5. Slip Casting; similar to sintering, with liquid mold-filling additives

6. Reaction Bonding; two phase mixture of SiC and Si, percentages and porosity vary with process

7. 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)

8. Hot Pressing; mechanical pressure compaction with electric current heating

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Selected Sources for SiC Selected Sources for SiC

1. BOOSTEC (Tarbes, France)

2. Cercom (Vista, CA)

3. Ceradyn (Costa Mesa, CA)

4. Coorstek (Golden, CO)

5. GE Power System Composites (Newark, DE)

6. IBCOL (Munich, Germany)

7. Kyocera Advanced Materials (Vancouver, WA)

8. Poco Graphite (Decatur, TX)

9. SSG Precision Optronics (Wilmington, MA) – no mat props.

10. Trex Enterprises (Lihue, HI)

11. Rohm & Haas (Woburn, MA)

12. Saint Gobain / Carborundum (Niagara Falls, NY)

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SiC fabrication - IBCOLSiC fabrication - IBCOL

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SiC fabrication - Boostec SiC fabrication - Boostec

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R. Temp SiC Material PropertiesR. Temp SiC Material PropertiesManuf. 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 450 634 4.3 3200 0.17 4.8 115

sintered 430 400 4.3 3200 0.17 4.5 120

Cercom CVI 460 570 4.4 3200 0.16 4.5 130

Coorstek CVD 462 468 3.5 3210 0.21 4.6 115

RB 462 462 4-5 3100 0.20 4.4 125

sintered 410 480 4-5 3150 0.21 4.4 150

GE Cesic C/SiC 197 120 4.6 2650 2.1 125

IBCOL C/SiC 235 175 2650 2.6 135

Kyocera 430 539 5.6 3200 0.16 4.0 63

Poco CVI 218 147 2.3 2530 0.17 1.2 170

Rohm-Haas CVD 466 461 3.3 3210 0.21 2.2 300

St.Gobain sintered 410 240 4.6 3100 0.14 4.0 125

Trex CVD 466 380 3.4 3200 0.17 3.5 205-250

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SiC Mat. Prop. ComparisonsSiC Mat. Prop. ComparisonsManuf. 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 CVD 462 468 3.5 3210 0.21 4.6 115

Rohm-Haas CVD 466 461 3.3 3210 0.21 2.2 300

Trex CVD 466 380 3.4 3200 0.17 3.5 205-250

GE Cesic C/SiC 197 120 4.62 2650 2.1 125

IBCOL C/SiC 235 175 2650 2.6 135

AlN 330 290 2.6 3260 0.24 4.5 170

Alum 7075-T6 72 50 24 2790 0.33 23.4 160

TZM Arc cast 325 860 6-30 10160 0.32 4.9 120

Molybdenum Stress rel. 330 415 10220 0.32 5.35 138

304 St. Stl. 193 500 346 8030 0.29 16.2 16

123/24/05 Bruce C. Bigelow -- UM Physics

SiC Space HeritageSiC Space Heritage

Heritage missions:

1. NASA EO-1 ALI – SiC mirrors

2. ESA ROCSAT2 – SiC optical bench

3. ESA ROSETTA – SiC optical bench

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SiC Space Heritage – EO1 SiC Space Heritage – EO1

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SiC Space Heritage – Rosetta SiC Space Heritage – Rosetta

Rosetta – SiC optics and optical bench

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SiC Space Heritage - ESASiC Space Heritage - ESA

IBCOL EADS/ESA verification structure

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SiC Space Applications - HershelSiC Space Applications - Hershel

3.5m SiC primary mirror

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SiC Space Applications - HershelSiC Space Applications - Hershel

Hershel SiC secondary mirror support structure

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ESA - GAIAESA - GAIA

GAIA optical layout – 2 fields simultaneously

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ESA - GAIAESA - GAIA

GAIA focal plane mosaic – 10 x 18 = 180 CCDs 4500 x 1966 px/CCD, 1.5 Gpx

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SiC Space Applications - GAIASiC Space Applications - GAIA

GAIA SiC primary mirror demonstrator - 1.4m x 0.5m

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SiC Space Applications - GAIASiC Space Applications - GAIA

GAIA SiC stability verification optical bench

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SiC Space Applications - GAIASiC Space Applications - GAIA

GAIA focal plane demonstrator model (Boostec):770mm by 580mm by 36mm, with a mass of about 8kg.

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SiC Space Applications - GAIASiC Space Applications - GAIA

GAIA focal plane - sintered SiC – detector mounting detail

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Silicon Carbide for SNAPSilicon Carbide for SNAP

Conclusions:

1. There are many commercial sources for SiC

2. SiC material production and fabrication methods are well developed

3. SiC and C/SiC demonstrate extremely high performance material properties

4. Space heritage for SiC has been established

5. NASA and ESA are using of SiC in current programs

6. SiC is a real option for SNAP, both for optics and structures