The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 09, 1986
Filed:
Apr. 08, 1985
Richard D Veltri, East Hartford, CT (US);
Francis S Galasso, Manchester, CT (US);
United Technologies Corporation, Hartford, CT (US);
Abstract
A method for repairing a multilayer coating on a carbon-carbon composite having a CVD silicon nitride outercoating by applying a coating of CVD silicon nitride. It has been found that if a multilayer coating containing CVD silicon nitride on a carbon-carbon composite is broken the entire composite will fail to survive at elevated temperatures due to oxidation. However, the deposition of silicon nitride on such a composite will affect repair such that the newly coated composite will substantially resist oxidation at temperatures up to 1750.degree. C. and above. Preferably the coated composite is maintained at a temperature of about 1500.degree. C. and a gaseous mixture containing silicon tetrafluoride and anhydrous ammonia is passed over the composite at a partial pressure of the reactant gases less than about 10 millimeters mercury.