High density high strength alpha sialon based article and process for producing same
US5032553A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 7, 1990 |
| Grant date | Jul 16, 1991 |
| Priority date | — |
| Expiry date | Dec 7, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/597
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A high density high strength ceramic article is disclosed having from about 70% to about 100% of its crystalline phases as alpha sialon, having less than about 20% by weight of its crystalline phases as beta sialon, having a density of greater than about 94% of the theoretical density, and having a flexural strength of greater than about 70 kpsi at about room temperature, a Knoop hardness of greater than about 14 GPa, and a Rockwell A hardness of greater than about 94. The process for producing the article is disclosed. The process involves forming a powder mixture consisting essentially of in percent by weight from about 48 to about 88 silicon nitride, from about 8 to about 30 aluminum nitride, from about 2 to about 16 of an oxygen containing compound of an element selected from the group consisting of yttrium, lithium, magnesium, calcium, scandium, cerium, rare earths, and combinations thereof, and from about 2 to about 12 of oxygen containing compounds of one or more metals as additives to aid densification, forming a green article from the mixture, and densifying the green article by one or more methods selected from the group consisting of sintering, sintering followed by hot …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.