Characterization and control of the fiber-matrix interface in ceramic ...

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80 graphite holders through multiple washings in acetone. The average fiber content of the resulting fiber preforms was 41.4 f 1.3 vol %. 9.3.2 Jntermediate coatine deDositioQ The preforms next were precoated with thin layers of various materials. The deposition parameters and nominal thicknesses of the films are summarized in Table 9.1. The coating runs were carried out using the following procedure. The preform was placed atop the graphite spacer, and Grafoil gaskets were used to seal the injector to the spacer and the preform to the spacer. Hot water of 355 K average temperature was supplied to the injector, whereas only cold water was passed through the furnace sections and electrodes. The apparatus was evacuated (with the exception of the MTS reservoir) to an ultimate pressure of < 0.5 torr using a rotary mechanical pump. The argon purges to the furnace base, shell, and sight port were set at appropriate levels (a total flow of 5 L/min), and argon was allowed to flow to the preform at a rate of 500 cm3/min through the reactant gas supply lines, subsequently flushing these lines at the same time. The furnace was then heated to the specified deposition temperature and the system was allowed to degas for 30 min. After these preliminary procedures, the operation pressure of the furnace was set on the controller and reactants were directed into the reaction chamber. The system was allowed to stabilize and then run at steady state for 2 hours. On completion, the reactant gases were replaced with argon gas flow and the furnace was cooled to room
81 Table 9.1. Precoating processing parameters. Reactant Ar Precoat Infiltration Sample Fiber flow diluent Temp. thicknessb time NO. ($1 Precoata (cm3/min) (cm3/min> (K) (P.4 (hours) - 170 41.8 si 500 675 0.17 24.8 171 41.3 Carbon 500 1375 0.03 21.3 172 42.1 Boron 500 775 0.50 26.1 173 39.0 sic 500 1125 0.08 23.7 174 41.8 Carbon 500 1375 0.12 21.7 175 43.5 Carbon 500 1375 0.07 22.0 176 42.0 sic 500 975 0.22 22.5 177 40.4 BN 40 (M3) 875 0.13 20.6 178 40.3 uncoated 500 1375 21.7 179 41.4 Mo 500 (H2) 1125 0.98 24.1 180 41.7 Carbon 500 1375 0.28 23.7 aAll precoat times - 2 hours. bCalculated from weight gain.
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ORNL/TM-11039 Metals and Ceramics D
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Page 9.3 Composite Fabrication . .
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LIST OF TABLES Table Page 5,l. Prop
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Figure 8.3. 9.1.. 9.2. 9.3. 9.4. 9.
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Figure 10.18. 10.19. 10.20. 10. 21.
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ACKNOWLEDGMENTS The author wishes t
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CWCTERIZATION AND CONTROL OF THE FI
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1. INTRODUCTION During the last sev
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The development of low-density, hig
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3. FABRICATION TECHNIQUES 3.1 Intro
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11 isostatic pressing (HIP), can be
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13 utilizing the comparatively low-
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16 ORN L- DWG 85- 4 i 4 18RS HEAT1
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5. COMPOSITE DESIGN 5.1 Introductio
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21 5,2 Mechanical Considerations Th
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23 GRNL-DWG 88-74 26 Figure 5.1. Th
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25 Equation (6) shows that the stre
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27 of reinforcement. There are two
Page 47 and 48: 29 in strength. Conversely, the fib
Page 49 and 50: -I_- Table 5.2. Thermally induced a
Page 51 and 52: 33 1.2 ID 0.8 ;.r 1 e fi v 0.6 a4 Q
Page 53: 35 will affect the interface and, t
Page 56 and 57: 38 fiber-matrix bonding; thus, a fu
Page 58 and 59: 40 In the analysis of the mechanica
Page 60 and 61: 42 1.2 I .o .6 - E f aa '3 0.6 cn 3
Page 62 and 63: 44 will result in the matrix being
Page 64 and 65: I I MATRIX MATRIX Figure 7.1. Schem
Page 66 and 67: 48 F = 2a2H, where H is the hardnes
Page 68 and 69: 50 OWL-PHOTO 6866-86 i d c I 20pm F
Page 70 and 71: 52 where Af is the surface area of
Page 72 and 73: 54 Figure 7.4. Tensile and shear st
Page 74 and 75: 56 I I I / -c rc -c / . Om / / I /
Page 76 and 77: 58 ORNL-OWG 87-i 8234 F Figure 7.7.
Page 78 and 79: coating and the distribution of she
Page 80 and 81: 62 O m PHOTO 6676-87 i SIC FIBERS -
Page 83 and 84: the composite, therefore an interme
Page 85 and 86: methane as the reactant and is, thu
Page 87 and 88: 9. EXPERIMENTAL PROCEDURES 9.1 Depo
Page 89 and 90: 71 furnace. The furnace is, therefo
Page 91 and 92: 73 further protection. A 6.5-cm-dia
Page 94 and 95: 76 of the specimen slowly decreased
Page 96 and 97: 78 The programmer is also equipped
Page 100 and 101: 82 temperature by simply switching
Page 102 and 103: 84 ORNk DWG 87- 4494 3 METAL LOGR A
Page 104 and 105: 86 9.5 Fracture Surface Analvsis Th
Page 106 and 107: 88 treated and untreated halves wer
Page 108 and 109: 90 9.8.2 Tensile testinq In an init
Page 110 and 111: 92 ORNL-DUG 85-11767R.2 ? ! 2 f CEN
Page 112 and 113: 94 fracture of individual Nicalon f
Page 114: 96 Figure 10.1. SiC-infiltrated Nic
Page 117 and 118: 99 compared with the dimensions acq
Page 119 and 120: 101 Table 10.3. Strength and modulu
Page 121 and 122: 100 ORNL- DWG 87-1 6292 R CVI-I73 7
Page 123 and 124: BULK FIBER SAMPLE NO. 173: FIBER SU
Page 125 and 126: 107 similar samples show the film o
Page 127 and 128: Figure 10.7. SEM micrographs showin
Page 129 and 130: 111 Table 10.4. Thermochemical eval
Page 131 and 132: 100 ORNL-DUG 87-15969R CVI- 170 75
Page 133 and 134: 115 Analysis conversion of of the m
Page 135 and 136: 117 A 1 I S N 31 N I I'd I LN 3H 3
Page 137 and 138: 119 n 0 W n 9 v P n w- n v
Page 139 and 140: 121 s m f c I m z - Ir 2 a 0 9 In u
Page 141 and 142: Figure 10.14. SEM micrographs of in
Page 143 and 144: J ORNL-DWC 88-6289 z cF u) w I- z O
Page 145 and 146: 127 300 I CVI-480 I I 1 0 R N L-DWG
Page 147 and 148: io0 I I I I CVI- 172 75 - - 0 z v -
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131 RAL 033021 RAL 033023 Figure 10
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133 include: the reaction of boron
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136 that BN coatings react with the
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75 7 ORNL-DWG 87-48234 50 - - c5 z
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140 Table 10.9. Thermochemical eval
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OANL-bwo 88-9025 ORNL-DWG 66-9027 I
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144 uncoated tows were 14 k 2 pm; t
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11. DISCUSSION 11.1 Constituent Pro
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149 The properties of CVD Sic have
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151 11.2.1 Matrix cracking In the N
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153 OWL-DWG 88-10677 CVI- (78 22 I
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155 Table 11.3. Property comparison
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157 a f ““f f- L c I Figure 11.
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159
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161 The equations demonstrate that
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163 calculations of the matrix depo
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165 In four of the samples, the fib
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167 Table 11.4. Properties of glass
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169 rare-earth magnets and coils to
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171 stress fields along the fiber i
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173 11.3.2 Tensile testinp, The use
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17 5 contraction have been ignored,
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177 the system, and when the result
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180 reduces fiber strength. The str
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182 15. R. A. J. Sambell, D. H. Bow
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184 41. A. J. Caputo et al., "Fiber
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186 71, N. F. DOW, Study of Stresse
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188 98. M. H. Rawlins et al., "Inte
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190 125. R. Warren and C-H. Anderss
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192 155. M. F. Doerner and W, D. Ni
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APPENDIX A. AUGER ELECTRON SPECTROS
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APPENDIX B DETAILS OF THE FIBER-SHE
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200 Those for the fiber (primed) ar
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202 89-92. 93. 94. 95" 96. 97. 98-9
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204 130-133. E. I. DUPONT DE NEMOUR
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206 173. NATIONAL ACADEMY OF SCIENC
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208 203 - 204. 20s. 206 - 207. 208.
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