Claims
- 1. A method of applying a carbon-rich surface layer to a silicon carbide filament comprising:
- supplying an elongated reactor through which a filament substrate moves, said reactor having an entrance port through which a hydrocarbon and silane mixture is supplied to vapor deposit stoichiometric silicon carbide on the substrate filament;
- an intermediate exit port for removing said mixture;
- a lower entrance port below said intermediate exit port through which a hydrocarbon and silane blend is supplied to flow counter to the movement of the filament to the exit port; and
- adjusting the vapor deposition rates of the hydrocarbon and silane blend so that the percentage of unreacted silane in the blend relative to unreacted hydrocarbon decreases as the blend moves from the lower entrance port to the exit port.
- 2. A process as described in claim 1 where the Si/C ratio at the surface of the carbon-rich surface layer is 0.3 to 0.5.
- 3. A process as described in claim 1 where the depth of the carbon-rich surface layer is from 0.7 to 1.3 microns.
- 4. A process as described in claim 1 where the blend of hydrocarbon to silane is 4 parts argon, 1 part propane and 0.02 parts dichlorosilane.
- 5. A process as described in claim 1 where the hydrocarbon is propane and the silane is dichlorosilane.
Parent Case Info
This is a division of application Ser. No. 173,773 filed July 30, 1980, now U.S. Pat. No. 4,340,636.
Government Interests
This invention is licensed to the U.S. Government under Contract No. N00014-79-C-0349 with the U.S. Air Force.
US Referenced Citations (5)
Divisions (1)
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Number |
Date |
Country |
Parent |
173773 |
Jul 1980 |
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