Search International and National Patent Collections

1. (WO1985001465) COATED SILICON NITRIDE CUTTING TOOLS

Pub. No.:    WO/1985/001465    International Application No.:    PCT/US1984/001142
Publication Date: Apr 11, 1985 International Filing Date: Jul 19, 1984
IPC: B23B 27/14
C04B 35/584
C04B 41/52
C04B 41/89
Applicants: GTE LABORATORIES INCORPORATED
Inventors: SARIN, Vinod, K.
BULJAN, Sergej-Tomislav
Title: COATED SILICON NITRIDE CUTTING TOOLS
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 lenthanide rare earth oxides, and mixtures thereof.