Preparation of high alpha-type silicon nitride powder
US5456896A · kind A · utility
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6References
7Claims
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Key dates
| Filing date | Jul 12, 1994 |
| Grant date | Oct 10, 1995 |
| Priority date | — |
| Expiry date | Jul 12, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B21/0682
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Silicon nitride powder is prepared by nitriding metallic silicon powder in a nitriding gas atmosphere at a temperature of 1,000.degree. C.-1,500.degree. C. Midway the nitriding step, the nitrided product is heat treated in an inert non-oxidizing gas atmosphere or vacuum at a temperature higher than the nitriding temperature, but lower than 1,600.degree. C. The product is nitrided again, obtaining high .alpha.-content silicon nitride powder.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.