Method of making a silicon nitride body from the Y.sub.2 O.sub.3 /SiO.sub.2 .sub.3 N.sub.4 /Al.sub.2 O.sub.3
US4443394A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 19, 1983 |
| Grant date | Apr 17, 1984 |
| Priority date | — |
| Expiry date | Jul 19, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/584
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method is disclosed of making a fully dense silicon nitride comprising object by heating a silicon nitride mixture containing yttrium silicon oxynitride (at least 75% Y.sub.10 Si.sub.6 O.sub.24 N.sub.2) to full density without the need for special atmospheres or packing mediums. A reaction bonded silicon nitride/yttrium silicon oxynitride comprising object is fabricated to have the oxynitride present in an amount of 5-17% by weight of the object, free silicon and other oxides in an amount up to 0.5%, and the remainder essentially silicon nitride. The object is heated in an ambient atmosphere to a temperature below the sublimation temperature of silicon nitride and for a period of time to fully densify the object as a result of solution of the silicon nitride into liquified oxynitride, the object being in direct contact with the ambient atmosphere during heating.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.