Effect of temperature grain size and cobalt content on hardness of tungsten carbide-cobalt: T.V.Milman et al. (Inst. for Problems in Materials Science, Kiev, Ukraine.) Int. J. Refractory Metals Hard Mater., vol 17, no 1–3, 1999, 39–44

Abstract

Ni doped Tungsten Carbide thin films (WC+Ni) were deposited onto stainless steel, WC–Co and glass substrates by non-reactive d.c. magnetron sputtering process using a sintered WC–6% Ni target. The WC+Ni hard coating films had thicknesses between 0.6 and 1.5 μm and were deposited at temperatures between 300°C and 550°C. The structure of the films was characterized using X-ray Diffraction (XRD), Secondary Ion Mass Spectroscopy (SIMS) and Reflection Absorption Infrared Spectroscopy (RAIRS) techniques. A morphological analysis was carried out using Atomic Force Microscopy (AFM) and SEM, while the microhardness was measured by nanoindentation. Reflection Absorption Infrared Spectroscopy results confirm that the WCx formation was dependant on substrate temperature. AFM and SEM analysis indicated that the surface morphology is formed by rounded grains. Hardness values deduced from microindentation curves by statistical average on each sample is 18 GPa for all the samples, the same value that has been found from the microindentation measurements on the bare WC substrate.