Coated composite silicon nitride cutting tools
US4441894A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 1983 |
| Grant date | Apr 10, 1984 |
| Priority date | — |
| Expiry date | Sep 26, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B41/89
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Cutting tools and cutting tool inserts having improved mechanical and chemical wear resistance under demanding conditions of machining speed, temperature, or workpiece hardness comprise a composite silicon nitride substrate having at least one intermediate hard 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 composite silicon nitride substrate body consists essentially of particles of a refractory material uniformly distributed in a matrix consisting 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 yttrium oxide, hafnium oxide, the lanthanide rare earth oxides, and mixtures thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.