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US 5,288,444 AGranted
Controlled resistivity ceramic fibers and process for making them
AssigneeHoechst Celanese Corporation
InventorsHarris A. Goldberg, Ilmar L. Kalnin, Clyde C. Williams
Life of this patent
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Abstract
Ceramic fibers formed by the pyrolysis of organosilicon preceramic polymers are provided with increased resistivity by treating the fibers in air at temperatures of less than 1,000.degree. C. to oxidize the free carbon content of the fibers.
Claims14
A process for increasing the resistivity of ceramic fibers which have been formed by pyrolyzing a fiber spun from an organosilicon preceramic polymer devoid of pendant or backbone oxygen comprising:
- contacting said ceramic fiber with an oxidizing agent at temperatures of about 400.degree.-750.degree. C. for a period of time sufficient to reduce the free carbon content of said fibers and provide a silicon carbide fiber of increased electric resistivity.
A process for manufacturing highly resistive ceramic articles comprising:
- pyrolyzing an article shaped from an organosilicon preceramic polymer devoid of pendant or backbone oxygen to yield a ceramic article and subsequently treating said ceramic article in an oxidizing atmosphere at temperatures of about 400.degree.-750.degree. C. for a period of time sufficient to reduce the free carbon content of said ceramic article and provide a ceramic article of increased electric resistivity.
Dependencies are inferred from the claim text.