Silicon nitride sintered bodies and a method for producing the same
US4640903A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1985 |
| Grant date | Feb 3, 1987 |
| Priority date | — |
| Expiry date | Sep 16, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/597
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Silicon nitride sintered bodies having particularly excellent strength and creep resistance at high temperature, in which a total amount of MgO and Al.sub.2 O.sub.3 is more than 7% by weight and not more than 30% by weight and a weight ratio of MgO/Al.sub.2 O.sub.3 is 5-15 and the remainder is mainly Si.sub.3 N.sub.4 and at least one of magnesium sialon crystal represented by the general formula Mg.sub.x/2 Si.sub.6-y+x/2 Al.sub.y-x O.sub.y N.sub.8-y (0<x.ltoreq.y<8, preferably 0.9.ltoreq.x/y) and forsterite crystal represented by the formula Mg.sub.2 SiO.sub.4 is contained as a second phase in addition to the main crystal of Si.sub.3 N.sub.4, are produced by mixing a raw material powder of silicon nitride containing not greater than 2% by weight of oxygen with MgO and Al.sub.2 O.sub.3 so that a total amount of MgO and Al.sub.2 O.sub.3 is from 7% by weight to 30% by weight and a weight ratio of MgO/Al.sub.2 O.sub.3 is 5-15, and firing the resulting mixture at a temperature of 1,650.degree.-1,850.degree. C. in nitrogen or an inert gas atmosphere.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.