Preceramic compositions and ceramic products
US4891340A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 18, 1988 |
| Grant date | Jan 2, 1990 |
| Priority date | — |
| Expiry date | Aug 18, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G77/62
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.