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:
Jun. 11, 1996
Filed:
Aug. 22, 1994
David C Sayles, Huntsville, AL (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
The conversion of carbon-carbon of a composite material at the surface to licon carbide-hybridized carbon-carbon in accordance with the method of invention is accomplished by reacting the carbon fibers and matrix with silicon monooxide at elevated temperature from about 1500.degree.-1700.degree. C. The conversion of bulk graphite or carbon-carbon composite materials is achieved in 30-60 minutes at 1700.degree. C. With conversion the density is increased from the density of carbon of 1.45 grams/cc to that of silicon carbide of 3.21 grams/cc. The method of reaction in the vapor phase of silicon monooxide with the carbon-carbon bond releases a C atom in exchange for the Si atom with a release of CO from the composite material. Photomicrographic studies indicates a depth of conversion from about 50 to 100 mils. The reaction rate of silicon monooxide increases with increased temperature; therefore, to avoid too rapid a release of the by-product carbon monooxide which might damage the composite material in its escape, the reaction temperature should not exceed 1700.degree. C.