Effect of carbon nanotubes content on microstructure and properties of WC/Ni laser cladding coatings

To enhance the mechanical properties of Ni–WC coatings, the carbon nanotubes were used as reinforced materials by laser cladding. Optical microscopy (OM), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to investigate the effect of CNTs content on the phase composition and microstructure. The microhardness and wear resistance were measured by Vickers hardness testing and friction wear testing. Experimental results showed that the new phases Cr2Fe14C are found in the coatings with CNTs, the grain size is finer than that of the coating without CNTs. The microhardness and wear resistance of the coatings with CNTs content ranging from 0 to 5 wt-% present increase initially and then decrease trend. The coatings with 3 wt-% CNTs have the highest microhardness and wear resistance, which proved that the appropriate amount of CNTs addition is 3 wt-%.