CVD-WC AND WCXNY DIFFUSION BARRIER COATINGS ON WC CO METALLOCERAMICS/

Conventional hard metal coatings on WC/Co metalloceramics are treated at elevated temperatures by cobalt diffusion. That could prevent apply ing suitable barrier sublayers. The paper presents results on the poss ibility tungsten carbide (WC) and carbonitrides (WCxNy) CVD layers to be used as a barrier against Co diffusion.. The coatings were prepared using two CVD methods: direct growing of WC or WCxNy and carborizatio n/carbonitridization of W films. The level of diffused Co was investig ated by X-ray microprobe technics, Auger electron spectrometry and dir ect layer by layer spectral analysis in the hollow cathode glow discha rge method. Results show that WC and WCxNy coatings are prospective fo r preventing diffusion interaction between the substrate and the funct ional coatings. (C) 1998 Elsevier Science B.V. All rights reserved.