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US 11,691,924 B2Granted
CVI matrix densification process
AssigneeRaytheon Technologies Corporation
InventorsYing She, Nitin Garg, Andrew J. Lazur, Olivier H. Sudre
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Abstract
Disclosed herein is a chemical vapor infiltration method including flowing ceramic precursors through a preform and depositing a matrix material on the preform at a first gas infiltration pressure, increasing the gas filtration pressure to a second gas infiltration pressure, and lowering the gas infiltration pressure to a third gas infiltration pressure which is intermediate to the first and second gas infiltration pressures.
Claims16
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 gas filtration pressure to a second gas infiltration pressure, and
- lowering the gas infiltration pressure to a third gas infiltration pressure which is intermediate to the first and second gas infiltration pressures;
- wherein the first pressure is less than or equal to 1 torr, and wherein the first pressure is 1 to 20% of the second pressure;
- wherein the second pressure is greater than 1 torr, and wherein the second pressure is maintained until infiltration gas diffusion rate rather than deposition rate controls matrix densification rate;
- and
- wherein the third pressure is 25 to 75% of the second pressure, and wherein the third pressure maintains matrix densification under reaction control rather than diffusion control.
4 more elements
A chemical vapor infiltration method comprising:
- flowing SiC ceramic precursors through a SiC preform in a reactor and depositing a SiC matrix material on the preform at a first gas infiltration pressure of the reactor,
- increasing the gas filtration pressure to a second gas infiltration pressure, and
- lowering the gas infiltration pressure to a third gas infiltration pressure which is intermediate to the first and second gas infiltration pressures;
- wherein the first pressure is less than or equal to 1 torr, and wherein the first pressure is 1 to 20% of the second pressure;
- wherein the second pressure is greater than 1 torr, and wherein the second pressure is maintained until infiltration gas diffusion rate rather than deposition rate controls matrix densification rate;
- and
- wherein the third pressure is 25 to 75% of the second pressure, and wherein the third pressure maintains matrix densification under reaction control rather than diffusion control.
4 more elements
Dependencies are inferred from the claim text.