Microstructure and properties of Co based laser cladded composite coatings

Coatings deposition using different materials and various techniques are a viable method to improve the surface properties of alloys, especially the surface strength with improved tribological properties. In this study, a series of Co-based reinforced composite coatings containing different ratios of WC–CoCr–Ni particles were fabricated by laser cladding onto the surface of an AISI 904L stainless steel substrate. The main goal of this experimental work was to determine the influence of the WC particle addition on the structure and properties of the obtained Co composite coating in terms of improving the sliding wear resistance without negative influence the corrosion resistance in chloride media. The effect of the WC particles onto the microstructure, phase composition, microhardness, wear and corrosion properties, was investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) in association with the evolution of the friction coefficient and that of the polarization curves, respectively. The achieved results have shown that the new phase composition, especially developed due to the remelting of the WC phase, led to an improvement of the wear resistance. No significant changes were recorded after the electrochemical tests evaluation.