Coating for protecting a carbon-carbon composite from oxidative degradation
AssigneeAllied-Signal Inc.
InventorsRoger Y. Leung, Bryan A. Weyneth
Life of this patent
Estimating the term…
Abstract
A process for forming a high temperature oxidation resistant coating on a carbon-carbon composite is disclosed and claimed. The process comprises applying a cyclosiloxane monomer blend containing a filler such as silicon carbide to a carbon-carbon composite, polymerizing and pyrolyzing said blend to form a filled black glass protective coating on the carbon-carbon composite.
Claims28
A method of forming a high temperature oxidation resistant coating on a carbon-carbon composite comprising the steps:
- (a) polymerizing a blend of a hydrosilylation catalyst, a filler and 1) a cyclosiloxane monomer of formula ##STR3## where n is an integer from 3 to about 20, R is hydrogen, and R' is an alkene having from 2 to about 20 carbon atoms and containing a vinyl-silicon bond, or 2) at least two different cyclosiloxane monomers of the same formula as above and with the same n integer value range where R' is an alkyl group of from 1 to about 20 carbon atoms and in one cyclosiloxane monomer R is hydrogen, and in the others R is an alkene of from 2 to about 20 carbon atoms containing a vinyl-silicon bond to produce a black glass precursor polymer containing a filler;
- (b) pyrolyzing said polymer precursor under a non-oxidizing gas atmosphere and at a temperature of about 700.degree. C. to about 1400.degree. C. for a time sufficient to form a black glass powder containing a filler;
- (c) reducing the particle size of the filled black glass powder;
- (d) mixing said reduced particle size black glass with a new portion of the blend of the cyclosiloxane monomers and hydrosilylation catalyst and optionally a filler of step (a) to form a slurry;
- (e) applying said slurry from step (d) to a carbon-carbon composite;
- (f) curing said coated carbon-carbon composite at curing conditions to produce a cyclosiloxane polymer coated carbon-carbon composite;
- (g) pyrolyzing said filled polymer coated carbon-carbon composite under a non-oxidizing gas atmosphere and at a temperature of about 700.degree. C. to about 1400.degree. C. for a time sufficient to produce a filled black glass containing coating on said carbon-carbon composite;
- and
- (h) recovering said filled black glass coated carbon-carbon composite.
A method of forming a high temperature oxidation resistant coating on a carbon-carbon composite comprising the steps:
- (a) applying a blend of a hydrosilylation catalyst and 1) a cyclosiloxane monomer of formula ##STR4## where n is an integer from 3 to about 20, R is hydrogen, and R' is an alkene having from 2 to about 20 carbon atoms and containing a vinyl-silicon bond, or 2) at least two different cyclosiloxane monomers of the same formula as above and with the same n integer value range where R' is an alkyl group of from 1 to about 20 carbon atoms and in one cyclosiloxane monomer R is hydrogen, and in the others R is an alkene of from 2 to about 20 carbon atoms containing a vinyl-silicon bond to a carbon-carbon composite to afford a coated carbon-carbon composite;
- (b) curing said coated carbon-carbon composite at curing conditions to produce a cyclosiloxane polymer coated carbon-carbon composite;
- (c) pyrolyzing said polymer coated carbon-carbon composite under a non-oxidizing gas atmosphere and at a temperature of about 700.degree. C. to about 1400.degree. C. for a time sufficient to produce a black glass coating on said carbon-carbon composite;
- and
- (d) recovering said black glass coated carbon-carbon composite.
A coated carbon-carbon composite comprising not less than 95% by weight of a carbon-carbon composite which has been coated with a filled black glass where said black glass has the composition SiC.sub.x O.sub.y in which x ranges from about 0.5 to about 2.0, y ranges from about 0.5 to about 3.0, and where the coating contains from about 15% to about 65% weight percent of a filler.
Dependencies are inferred from the claim text.