Preparation of high .alpha.-type silicon nitride powder
US5441694A · kind A · utility
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4References
19Claims
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Key dates
| Filing date | Jun 10, 1994 |
| Grant date | Aug 15, 1995 |
| Priority date | — |
| Expiry date | Jun 10, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2004/62
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In a method for preparing a high .alpha.-type silicon nitride powder by adding to and mixing with metallic silicon powder a copper catalyst and nitriding the mixture in a non-oxidizing gas atmosphere containing nitrogen or ammonia at 1,000.degree. to 1,500.degree. C., the amount of copper catalyst is limited to from 0.05 % to less than 0.5 % by weight of copper based on the weight of the metallic silicon. There is obtained silicon nitride powder of high purity at low cost and high efficiency since the copper catalyst can be efficiently removed from the silicon nitride powder through conventional acid treatment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.