Some aspects of a sputtered interfacial eta-carbide layer and its effect on a TiC-coated WC-Co cemented carbide

Abstract

A WC-Co cemented carbide was sputter coated with eta-carbide (Co ₆ W ₆ C) and TiC layers. The Co ₆ W ₆ C sputtered coating formed amorphously at all times, but heat treatment at 700°C for 1 h resulted in crystallization. TiC sputtered coatings were either amorphous or crystalline, depending on substrate temperature and composition. Amorphous TiC coatings crystallized when heat treated at 800°C. Sputtering did not change the stoichiometry of either the Co ₆ W ₆ C or the TiC coatings as long as there was no oxygen in the sputtering system. Single coatings of Co ₆ W ₆ C and TiC and dual coatings of TiC-Co ₆ W ₆ C were tool-life tested, and it was found that CO₆W₆C definitely contributed to longer tool life in continuous-cutting tests.