Compositions: ceramic – Ceramic compositions – Carbide or oxycarbide containing
Patent
1988-08-18
1990-01-02
Bell, Mark L.
Compositions: ceramic
Ceramic compositions
Carbide or oxycarbide containing
501 90, C04B 3556
Patent
active
048913405
ABSTRACT:
Low density SiC ceramics having improved bending and specific strengths are prepared by (A) intimately mixing about 50-85% by weight of SiC powder with about 15-50% by weight of a preceramic polysilazane binder, (B) pulverizing the mixture to form particles having a particle size smaller than 105 micrometers, (C) separating from those particles any particles having a particle size larger than about 105 micrometers, (D) molding the resultant composition having a particle size not larger than about 105 micrometers, and (E) pyrolyzing the molded composition in an inert atmosphere to a temperature of about 1200.degree.-1450.degree. C.
In a preferred embodiment of the invention, the preceramic binder is at least one polysilazane prepared by reacting an organodihalosilane with ammonia, treating the ammonolysis product with a basic catalyst which is capable of deprotonating an NH group that is adjacent to an SiH group, and quenching the resultant product with an electrophilic quenching reagent.
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patent: 4560526 (1985-12-01), Okumura
patent: 4639501 (1987-01-01), Seyferth et al.
patent: 4645807 (1987-02-01), Seyferth et al.
patent: 4650837 (1987-03-01), Seyferth et al.
patent: 4659850 (1987-04-01), Saitama et al.
Shin Nisso Kako Co., Ltd.-SiC Products by PPMC Process.
Rogers John J.
Semen John
Bell Mark L.
Ethyl Corporation
Green Anthony J.
Hogan Patricia J.
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