Ceramic cutting tool formed from Si.sub.3 N.sub.4 -Y.sub.2 O.sub.3 -SiO.sub .
US4401617A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 1981 |
| Grant date | Aug 30, 1983 |
| Priority date | — |
| Expiry date | Feb 9, 2001 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23B27/148
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method is disclosed comprising placing in a hot pressing environment a controlled mixture of a first powder of Si.sub.3 N.sub.4 containing a controlled amount of SiO.sub.2 (with or without a limited amount of milling media) with a second powder consisting essentially of Y.sub.2 O.sub.3, hot pressing the controlled mixture, and cooling the resultant unitary object. A novel silicon nitride comprising a unitary object is disclosed which can be shaped to form a novel cutting tool useful for machining metal such as cast iron. The object has selected crystalline phases formed beta Si.sub.3 N.sub.4 and beta prime Si.sub.3 N.sub.4 and as intergranular crystalline secondary phases consisting essentially of YSiO.sub.2 N, y.sub.10 Si.sub.17 N.sub.4 O.sub.23 and Y.sub.2 Si.sub.2 O.sub.7 with the YSiO.sub.2 N phase representing at least a 25% volume fraction of the secondary phases and comprising essentially all of the yittria-silicon oxide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.