Silicon carbide coated article with ceramic topcoat
AssigneeEthyl Corporation
InventorsWilliam E. Moehle, Leonard M. Niebylski
Life of this patent
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Abstract
Silicon carbide-coated carbonaceous substrates are overcoated with one or more ceramic layers derived from an organoborosilazane polymer solution containing 0-60% by weight of dispersed ceramic or preceramic powdered solids to seal the silicon carbide coating and provide better resistance to oxidative deterioration at elevated temperatures; the organoborosilazane polymer being the product obtained by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysilazane in an organic solvent. The thus-coated substrates are optionally overcoated with a buffer layer and then with one or more ceramic layers derived from polysilazane solutions or dispersions.
Claims7
An article comprising (1) a silicon carbide-coated carbonaceous substrate which is normally susceptible to oxidative deterioration and (2) a ceramic topcoat derived by the application, drying, and pyrolysis of an organoborosilazane polymer solution containing 0-60% by weight of dispersed ceramic or preceramic powdered solids;
- said polymer being the product obtained by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysilazane in an organic solvent.
A process which comprises (1) overcoating a silicon carbide-coated carbonaceous substrate with an organoborosilazane polymer solution containing 0-60% by weight of dispersed ceramic or preceramic powdered solids, said polymer being the product obtained by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysilazane in an organic solvent, (2) drying the coating, and (3) pyrolyzing the polymer at a temperature of about 675.degree. C.-900.degree. C.
Dependencies are inferred from the claim text.