Characterisation of laser modified WC-CoCr coatings

Abstract

In this work the affects of laser characteristics on surface morphology, microstructure, microhardness and wear rates of high velocity oxygen fuel (HVOF) WC–CoCr coatings were investigated. Continuous and pulsed laser treatments were applied on the HVOF coatings using a CO2 laser of 10.6 μm wavelength. Continuous laser treatment significantly improved homogeneity of the coatings. Pulsed laser treatment produced significantly higher discontinuities compared to continuous mode. Microhardness increased by 45% for continuous mode laser modified WC-CoCr coatings. However, wear resistance deteriorated, with a notable 40% increase in wear rate. The variations in coating properties were attributed to the re-melting and rapid quenching of the CoCr bonding matrix allowing for WC redistribution.