Methods of forming ceramic materials and ceramic products, and ceramic materials and ceramic products formed thereby
US4506020A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 23, 1983 |
| Grant date | Mar 19, 1985 |
| Priority date | — |
| Expiry date | Feb 23, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/597
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of producing a dense ceramic product comprises the steps of mixing a ceramic powder containing a major proportion of an alpha-phase substituted silicon nitride obeying the formula M.sub.x (Si,Al).sub.12 (O,N).sub.16, where x is not greater than 2 and M is a modifying cation (e.g. yttrium, calcium, lithium, magnesium, cerium) with at least one nitride of silicon and/or alumina wherein the alumina represents not more than 10% by weight of the mixture; and sintering the mixture in a non-oxidizing atmosphere at a temperature of 1700.degree. C. to 1900.degree. C. so as to produce (1) a dense ceramic product consisting essentially of beta-phase substituted silicon nitride having the general formula Si.sub.6-z Al.sub.z N.sub.8-z O.sub.z, where z is greater than zero and not greater than 1.5, and 0.05% wt to 20% wt of a further phase containing said modifying cation M, or (2) a dense ceramic product consisting essentially of said beta-phase substituted silicon nitride a 0.05% wt to 90% wt of an alpha-phase substituted silicon nitride obeying said formula M.sub.x (Si,Al).sub.12 (O,N).sub.16 and a minor amount of a further phase containing said modifying cation M.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.