Ceramics Process Systems Corporation

Wen-Cheng J Wei

Richard W Adams

Bruce E Novich

Whisker reinforced composites having improved strength and toughness are prepared by a process including densification by essentially pressureless sintering. There is no need to hot press or hot isostatic press to achieve a density of 99+% of theoretical for 10 vol. % whiskers and 93+% for 20 vol. % whiskers. The composites are derived from the desired volume fraction of whiskers, a sintering aid preferably submicron in average size range, and a major portion of a pressureless sinterable matrix material having an average particle size of not more than about 0.5 micron. Yttria-alumina composites are sintered at less than about 1800.degree. C. and for less than about two hours to avoid surface degradation.

Method for preparing dense, pressureless sintered SiC whisker reinforced

A refractory article and a process for making the same are provided. The article is derived from dissociated zircon and zirconia (99:1 to 80:20, weight basis). These components are formed into a slip, which can be conventionally processed to provide a sintered article. The resulting article can be subsequently heat treated to react any resulting glass phase with the zirconia present; further, the heat treated article can be subsequently redensified. These refractories are well-suited for such applications as tundish nozzle inserts and sliding gate valves.

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Jamaica Plain, MA, United States of America

Wen-Cheng J Wei