An Electron Diffraction Study of the Oxide Formed on Cemented Tungsten Carbide—Titanium Carbide Cutting Tools

Abstract

The oxide protecting the surface of cemented carbide cutting tools containing both tungsten and titanium carbides is identified by electron diffraction as Ti2 O3 , which is formed during the cutting operations. This is a protective and adherent oxide which is formed as an intermediate layer between the TiC-TiO solid solution (the titanium carbide particle) and an outer layer of TiO2 . The outer layer of TiO2 is spolled off by the abrasive action of the chip and only the Ti2 O3 layer protects against welding of the chip fragments to the tool; and the protective layer retards tool wear.