Silicon nitride sintered bodies and process for manufacturing the same
US4795724A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 1987 |
| Grant date | Jan 3, 1989 |
| Priority date | — |
| Expiry date | Jun 4, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/5935
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Silicon nitride sintered bodies are disclosed, which each consist essentially of Si, O, N, and at least two kinds of rare earth elements selected from Y, Er, Tm, Yb, and Lu the bodies comprising not less than 70% by weight of Si.sub.3 N.sub.4. The ratio of the molar amount of all the rare earth elements contained in the sintered body calculated as moles of Ln.sub.2 O.sub.3, Ln being a rare earth element selected from Y, Er. Tm, Yb and Lu divided by the molar amount of oxygen calculated as moles of SiO.sub.2 is within the range of from 0.4 to 1.3. The amount of oxygen calculated as moles of SiO.sub.2 is obtained by subtracting the amount of oxygen contained in all the Ln.sub.2 O.sub.3, all the rare earth elements contained in said sintered body being considered as molecules of Ln.sub.2 O.sub.3 from the amount of oxygen contained in the sintered body and converting the remaining amount of oxygen into moles of SiO.sub.2. Any one of the rare earth elements contained in the sintered body accounts for not more than 95 mol % of all the rare earth elements contained in the sintered body. An intergranular phase of Si.sub.3 N.sub.4 grains contained in the sintered body is substantially of a …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.