Continuous process for the preparation of silicon nitride by carbonitriding and silicon nitride thereby obtained
US5662875A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1996 |
| Grant date | Sep 2, 1997 |
| Priority date | — |
| Expiry date | May 8, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/12
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The present invention relates to a new process for the manufacture of fine powder of silicon nitride, to this powder and to the sinters obtained from the latter. The process comprises the reaction, in a nitrogen countercurrent and in continuous fashion, of silica, carbon and a seed crystal, in the presence of a volatile compound of a metal chosen from the group consisting of Be, Mg, Ca, Sr, Ge, Sn, Ti, Hf, Na and Ba, in a reaction zone possessing a temperature gradient, comprising a hot zone in which the said metal compound passes into the gaseous state and a cold zone in which the said metal compound in the gaseous state condenses, the said metal compound in the gaseous state being carried from the hot zone to the cold zone by the nitrogen countercurrent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.