Use of x-ray photoelectron spectroscopy for the investigation of the surfaces of hard-alloy parts machined with polycrystalline superhard materials

Abstract

The thin (<600 A) surface layers forming on VK20 and VK20K hard alloys during machining with polycrystalline superhard tool materials and diamond grinding under recommended conditions consist chiefly of tungsten and cobalt oxides, cobalt containing dissolved tungsten and carbon, and pure tungsten (or the compound W2C). The formation of such layers must be regarded as a beneficial phenomenon, because the presence on the surface of a tool material of a thin layer of oxides of the elements of which the material is composed helps reduce tool wear.