United States of America As Represented by the Secretary of the Air Force

The United States of America As Represented by the United States

Msnw LLC

George H Reynolds

Barry W McQuillan

Norbert B Elsner

Clyde H Shearer

This invention is a fiber-reinforced ceramic matrix composite and a method for their fabrication. The precursors of the ceramic matrix phase are impregnated into the fibrous preform or-applied to the surface of the fiber as fluids. The preform or fibers are then thermally processed to convert the precursor compounds to the desired refractory materials, e.g., carbides, borides, or nitrides. The density and other properties of the composites may be enhanced further by using a hybrid process that combines fluid infiltration and thermal treatment with chemical vapor infiltration.

Preparation of ceramic matrix composites by infiltration of fibrous preforms with fluids or slurries and subsequent pyrolysis

Ceramic metal oxide fibers are made by intercalating graphitic graphite fibers with a mixture of metal chlorides and then heating the intercalated fibers to oxidize or burn off the carbon leaving a metal oxide fiber having generally the shape and structure of the graphite fiber precursors to make composite fibers, such as binary fibers of aluminum oxide-zirconium oxide and aluminum oxide-ferric oxide.

Preparation of metal oxide fibers from intercalated graphite fibers

Carbon-graphite fibers are coated with a protective metal oxide coating by intercalating the fibers with a metal chloride and then deintercalating the chlorine by hydrolysis to form a metal oxide over the fibers. An example using aluminum chloride to form an aluminum oxide coating is described.

Process for making coatings on graphite using intercalated species

Lanthanum sulfide is maintained in the stable cubic phase form over a temperature range of from 500.degree. C. to 1500.degree. C. by adding to it small amounts of calcium, barium, or strontium. This novel compound is an excellent thermoelectric material.

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San Marcos, CA, United States of America

George H Reynolds