The influence of HVOF powder feedstock characteristics on the abrasive wear behaviour of CrxCy–NiCr coatings

CrxCy–NiCr cermet coatings are commonly utilised in industry as a means to provide wear resistance in high temperature environments. Such coatings are usually deposited by thermal spraying. In this work, CrxCy–NiCr coatings have been deposited using a Miller Thermal/UTP Top Gun high velocity oxy-fuel spray system from three commercially available powders, namely a sintered and crushed powder, a blended powder and a composite powder. The characteristics of the powder feedstock have a strong influence on the coating microstructures, although the coating microstructure is often very different to that of the powder due to processes that occur during spraying and rapid solidification of the splats. Coating microstructures were assessed by X-ray diffraction, scanning electron microscopy and microhardness measurements.