The Carborundum Company

Kennecott Corporation

John A Coppola

Carl H McMurtry

Laurence N Hailey

Yorihiro Murata

Richard H Smoak

Harry A Lawler

Lawrence N Hailey

Pressureless sintered silicon carbide ceramic bodies, having an equiaxed microstructure and an alpha crystalline habit can be produced by firing shaped bodies, containing finely divided silicon carbide, boron source such as boron carbide, carbon source such as phenolic resin and a temporary binder, at a sintering temperature of from about 1900.degree. C. to about 2250.degree. C., depending on the sintering atmosphere, under conditions such that a coating of carbon source is maintained on the finely divided silicon carbide, and sufficient boron is maintained within the shaped body during firing. Boron can be maintained within the shaped body by various techniques, such as the use of a 'seasoned boat' or graphite container for the body being sintered, which has been saturated with boron by exposure to boron at or about the temperature of sintering. There is also disclosed a process for producing a sintered silicon carbide ceramic body, with or without the equiaxed crystal microstructure, from silicon carbide powders of alpha or beta crystal structure, or amorphous noncrystalline silicon carbide, or mixtures thereof.

Sintered alpha silicon carbide ceramic body having equiaxed

Pressureless sintering of silicon carbide to produce ceramic bodies having 75% and greater theoretical densities, can be accomplished by firing shaped bodies, containing finely divided silicon carbide, boron source such as boron carbide, carbon source such as phenolic resin and a temporary binder, at a sintering temperature of from about 1900.degree. C. to about 2500.degree. C.

Sintered silicon carbide ceramic body

A method for making a dense thermal shock resistant silicon carbide ceramic body by hot pressing a blend of silicon carbide and from about 0.2 to about 2 weight percent of aluminum diboride and the resulting body.

High density hot pressed thermal shock resistant silicon carbide

A dense thermal shock resistant silicon carbide ceramic body and its method of manufacture which comprises heat sintering a shaped body comprising particulate silicon carbide and an additive selected from boron nitride, boron phosphide, aluminum diboride and mixtures thereof.

High density thermal shock resistant sintered silicon carbide

Pressureless sintering of silicon carbide to produce ceramic bodies having 75% and greater theoretical densities, can be accomplished by firing shaped bodies, containing finely divided silicon carbide, boron source such as boron carbide, carbon source such as phenolic resin and a temporary binder, at a sintering temperature of from about 1900.degree. C to about 2500.degree. C.

Process for producing sintered silicon carbide ceramic body

A powder containing substantial amounts of alpha phase silicon carbide suitable for use in subsequent sintering operations to obtain a high-density, high-strength ceramic product is described. The powder may consist substantially entirely of alpha silicon carbide or may consist of mixtures of alpha and beta phase silicon carbide. The silicon carbide powder of the present invention has an average particle size of from about 0.10 to about 2.50 microns and may contain maximum amounts of the following materials by weight based upon 100 parts of powder.

Silicon carbide powder compositions

Disclosure is made of a high-density, high-strength silicon carbide ceramic material that is produced using a silicon carbide powder containing boron or boron-containing compound as a densification additive by the utilization of boron in the sintering atmosphere.

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Lewiston, NY, United States of America

John A Coppola