Avco Corporation

Harold E Debolt

Thomas W Henze

James A Cornie

Raymond J Suplinskas

Albert W Hauze

The invention relates to a surface treatment for stoichiometric silicon carbide. A carbon-rich silicon carbide layer is applied over the silicon carbide. In the case of the silicon carbide surface, the ratio of silicon to carbon in the carbon-rich layer varies from one at the silicon carbide interface to near zero in the interior of the carbon-rich layer to greater than zero and preferably 0.3 to 0.5 on the surface of the carbon-rich layer remote from the interface. A preferred method of making the silicon carbide layer is also presented.

Coated stoichiometric silicon carbide

The invention is directed to a method of making a high strength-high modulus boron filament on a carbon substrate which is coated with pyrolytic graphite. Boron is deposited over the pyrolytic graphite. A preferred method of making such a filament citing specific pyrolytic graphite deposition temperatures is described.

Carbon filament coated with boron and method of making same

A refractory substrate, which generally is graphite or carbon is overcoated with silicon carbide by chemical vapor deposition from gaseous sources of silicon and carbon. The deposition generally takes place in combination with hydrogen and the coating on the substrate generally has a thickness at least equal to the diameter of the substrate itself. A silicon carbide filament containing an inner and outer surface layer of carbon rich silicon carbide, together with a method of making the same, is described.

Silicon carbide filaments and method

A filamentary reinforcement product for composites used in applications requiring high strength and high modulus of elasticity materials, particularly under high temperature service conditions, comprises one mil thick or thicker coatings of boron or boron carbide on a substrate which comprises about a one mil diameter carbon substrate having a catalytically transformed skin layer of highly oriented graphite formed from the carbon substrate using a boron catalyst.

Filamentary reinforcement product

A filamentary reinforcement product for composites used in applications requiring high strength and high modulus of elasticity materials, particularly under high temperature service conditions, comprising one mil thick or thicker coatings of boron or boron carbide on a substrate which comprises about a one mil diameter carbon substrate having a catalytically transformed skin layer of highly oriented graphite formed from the carbon substrate using a boron catalyst.

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Andover, MA, United States of America

Harold E Debolt