Silicon Carbide Manufacturing Processes and Material Properties B

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

Silicon 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 • • • 3/24/05 Space science applications Military applications Structures and reflecting optics Bruce C. Bigelow -- UM Physics 2

Silicon Carbide for SNAP This talk: 1. 2. 3. 4. 5. 6. 7. 3/24/05 Brief history Manufacturing processes Commercial sources Material properties Spacecraft heritage Current applications Conclusions Bruce C. Bigelow -- UM Physics 3

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” – Si. C created intentionally by passing current through a mixture of clay and carbon • “Natural” Si. C found only in meteorites, in very small quantities 3/24/05 Bruce C. Bigelow -- UM Physics 4

Silicon Carbide for SNAP Si. C Raw Material Production: 1. Acheson Process – for producing powders 2. Pyrolysis – for producing fibers 3. Reactions of silicon and carbon – for producing whiskers 3/24/05 Bruce C. Bigelow -- UM Physics 5

Si. C Production Processes 1. 2. 3. 4. 5. 6. 7. 8. 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/Si. C), 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 Si. C 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 6

Selected Sources for Si. C 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) 3/24/05 Bruce C. Bigelow -- UM Physics 7

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

Si. C fabrication - Boostec 3/24/05 Bruce C. Bigelow -- UM Physics 9

R. Temp Si. C Material Properties Manuf. Process E, GPa Boostec sintered 420 Ceradyne CVD Kic, MPa*m 0. 5 Density, kg/m^3 Poisson ratio 450 3. 5 >3100 0. 16 4. 0 180 440 375 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 4 -5 3100 0. 20 4. 4 125 sintered 410 480 4 -5 3150 0. 21 4. 4 150 GE Cesic C/Si. C 197 120 4. 6 2650 2. 1 125 IBCOL C/Si. C 235 175 2650 2. 6 135 430 539 5. 6 3200 0. 16 4. 0 63 Kyocera Fl. Str, Mpa CTE, ppm/C K, W/m*K 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 3/24/05 Bruce C. Bigelow -- UM Physics 10

Si. C Mat. Prop. Comparisons Manuf. Process E, GPa Ceradyne CVD 440 Coorstek CVD Rohm-Haas Fl. Str, Mpa Kic, Mpa-m-0. 5 Density, kg/m^3 Poisson ratio 375 3. 1 3200 0. 17 4. 5 200 462 468 3. 5 3210 0. 21 4. 6 115 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/Si. C 197 120 4. 62 2650 2. 1 125 IBCOL C/Si. C 235 175 2650 2. 6 135 Al. N 330 290 2. 6 3260 0. 24 4. 5 170 Alum 7075 -T 6 72 50 24 2790 0. 33 23. 4 160 6 -30 10160 0. 32 4. 9 120 10220 0. 32 5. 35 138 8030 0. 29 16. 2 16 TZM Arc cast 325 860 Molybdenum Stress rel. 330 415 193 500 304 St. Stl. 3/24/05 346 Bruce C. Bigelow -- UM Physics CTE, ppm/C K, W/m*K 11

Si. C Space Heritage missions: 1. NASA EO-1 ALI – Si. C mirrors 2. ESA ROCSAT 2 – Si. C optical bench 3. ESA ROSETTA – Si. C optical bench 3/24/05 Bruce C. Bigelow -- UM Physics 12

Si. C Space Heritage – EO 1 3/24/05 Bruce C. Bigelow -- UM Physics 13

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

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

Si. C Space Applications - Hershel 3. 5 m Si. C primary mirror 3/24/05 Bruce C. Bigelow -- UM Physics 16

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

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

ESA - 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 19

Si. C Space Applications - GAIA Si. C primary mirror demonstrator - 1. 4 m x 0. 5 m 3/24/05 Bruce C. Bigelow -- UM Physics 20

Si. C Space Applications - GAIA Si. C stability verification optical bench 3/24/05 Bruce C. Bigelow -- UM Physics 21

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

Si. C Space Applications - GAIA focal plane - sintered Si. C – detector mounting detail 3/24/05 Bruce C. Bigelow -- UM Physics 23

Silicon Carbide for SNAP Conclusions: 1. There are many commercial sources for Si. C 2. Si. C material production and fabrication methods are well developed 3. Si. C and C/Si. C demonstrate extremely high performance material properties 4. Space heritage for Si. C has been established 5. NASA and ESA are using of Si. C in current programs 6. Si. C is a real option for SNAP, both for optics and structures 3/24/05 Bruce C. Bigelow -- UM Physics 24