CPC C04B 35/80 (2013.01) [C04B 35/62863 (2013.01); C04B 35/62884 (2013.01); C23C 16/045 (2013.01); C23C 16/45557 (2013.01); C04B 2235/3826 (2013.01); C04B 2235/5244 (2013.01); C04B 2235/5252 (2013.01); C04B 2235/614 (2013.01)] | 19 Claims |
1. A chemical vapor infiltration method comprising:
flowing ceramic precursors through a preform in a reactor and depositing a matrix material on the preform at a first gas infiltration pressure of the reactor;
increasing the first gas filtration pressure to a second gas infiltration pressure; and
lowering the second gas infiltration pressure to a third gas infiltration pressure which is intermediate to the first and second gas infiltration pressures;
wherein the second gas infiltration pressure is maintained until infiltration gas diffusion rate rather than deposition rate controls matrix densification rate; and
wherein the third gas infiltration pressure maintains matrix densification under reaction control rather than diffusion control.
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