The Dow Chemical Company

David W Susnitzky

Donald R Beaman

Alan W Weimer

Stephen D Dunmead

Glenn A Eisman

Gene A Cochran

Kevin J Nilsen

Daniel F Carroll

Chinmau J Hwang

Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

Silicon nitride/silicon carbide composite densified materials prepared

Silicon carbide/silicon nitride composites are prepared by carbothermal reduction of crystalline silica powder, carbon powder and optionally crsytalline silicon nitride powder. The crystalline silicon carbide portion of the composite has a mean number diameter less than about 700 nanometers and contains nitrogen.

Method for producing silicon nitride/silicon carbide composite

Silicon nitride/silicon carbide composite powders

A dense, substantially glass free, SiAlON ceramic material and method of making such material. The material has at least an alpha-SiAlON phase and a beta-SiAlON phase and exhibits excellent high temperature oxidation resistance and strength, good room temperature toughness and hardness, and a density greater than at least 95 percent of theoretical. The method of making the ceramic material is simple and includes adding AlN in an amount sufficient to allow formation of a desired amount of alpha-SiAlON, and in addition, convert SiO.sub.2 and Al.sub.2 O.sub.3 into the beta-SiAlON phase, preferably, by adding AlN in an amount between about 1.3X+0.08Y-0.0045XY and about 1.3X+0.2Y-0.0024XY, wherein X is a weight percent of the SiO.sub.2 based on total weight of the Si.sub.3 N.sub.4 in the mixture and Y is a weight percent of alpha-SiAlON phase desired.

SiAlON composites and method of preparing the same

Growing community of inventors

Midland, MI, United States of America

David W Susnitzky