Coated silicon nitride cutting tools
US4449989A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1983 |
| Grant date | May 22, 1984 |
| Priority date | — |
| Expiry date | Sep 26, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B41/89
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Coated cutting tools and coated cutting tool inserts having improved mechanical and chemical wear resistance under demanding conditions of machining speed, temperature, or workpiece hardness comprise a silicon nitride substrate body having at least one hard, intermediate adherent coating layer of a refractory material and an outer adherent coating layer. The intermediate adherent coating layer has a different chemical composition than the outer adherent coating layer. The silicon nitride substrate body consists essentially of a first phase of silicon nitride and a refractory second phase comprising silicon nitride and an effective amount of a densification aid selected from the group consisting of silicon dioxide, aluminum oxide, magnesium oxide, yttrium oxide, hafnium oxide, zirconium oxide, the lanthanide rare earth oxides, and mixtures thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.