Process for the preparation of silicon carbide whiskers
US4904622A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 19, 1988 |
| Grant date | Feb 27, 1990 |
| Priority date | — |
| Expiry date | Feb 19, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B29/36
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The invention relates to a process for the preparation of silicon carbide whiskers by the reaction, in a non-oxidizing atmosphere, at a temperature of at least 1300.degree. C., of a charge composed of a mixture of carbon black and a source of silicon oxide, in which process the carbon black has an oxidability rate (measured by heating in air for 30 minutes at 600.degree. C.) of at least 85%, the silicon oxide source has a grain size of less than 100 .mu.m and the rate of rise in temperature between 1300.degree. and 1600.degree. C. is less than 30.degree. C.min.sup.-1 per minute if a static atmosphere prevails and at most 25.degree. C.min.sup.-1 if gas percolated. A stage of from 5 min to 5 h at 1600.degree. C. is optionally carried out. The carbon is preferably introduced into the reaction mixture in an over-stoichiometric quantity relative to the silica. The excess carbon is removed at the end of the reaction by oxidation in air at about 600.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.