Structure and properties of TiC x layers prepared by plasma-assisted chemical vapour deposition methods

Abstract

The preparation of hard coatings on hard metal substrates (WC/Co) using a d.c.-plasma glow discharge method is described. The Ti8C x coatings were deposited from the gas phase with starting gases TiCl 4, hydrogen, argon and a carbon source (benzene or n-heptane). The deposition temperature was chosen as 950 K. The film deposition rate was in the range 10–30 μm h −1. The coatings obtained were smooth and of small grain size (10–30 nm). Interface interactions between the layer and the substrate were not observed. The structure of the TiC x coatings were analysed by electron microscopy and X-ray diffraction. The measured Vickers microhardness passes through a maximum, dependent on the gas phase composition. No change in structure and texture was observed by variation of the carbon source (benzene or n-heptane).