A Comparative Study on the Surface Properties of WC/Co Alloy Coating and Co-based Alloy Coating by Ultra-high Speed Laser Cladding
WC/Co alloy coating and Co-based alloy coating were prepared on the surface of 304 stainless steel substrate by ultra-high-speed laser cladding technology.The microstructure,micro-hardness,friction coefficient and corrosion resistance of the two coatings were compared and analyzed.The results of research show that the microstructure of the two coatings have no microscopic cracks and porosity defects,the solidification microstructure changes from columnar crystal to equiaxial dendrites structure from the interface to the coating surface,a good metallurgical bond is formed between the coating and the substrate,and the overall microstructure of WC/Co alloy coating is more uniform and finer than that of Co-based alloy coating;The microhardness of WC/Co alloy coating is significantly higher than that of Co-based alloy coating,and the friction coefficient is lower than that of Co-based alloy coating,indicating that the wear resistance of WC/Co alloy coating is better than that of Co-based alloy coating.The electrochemical corrosion potential of Co-based alloy coating is higher than that of the WC/Co alloy coating,but the corrosion current density is lower than that of WC/Co alloy coating.Therefore,the corrosion resistance of Co-based alloy coating is better than that of the WC/Co alloy coating.
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