A Study On Microstructure And The Wear Resistant Of Laser Cladding Ni/wc Composite Coating

It is an effective method to improve properties of metal surface layer when metal was coated. The coating can resist wear and corrosion of the surface, it also can increase the strength of the metal. Therefore, it is important that coating and coating properties were studied. With experimental method, microstructure, phase, microhardness and wear resistant in different depth of laser cladding Ni-base alloy WC composite coating were investigated.The microstructure of the coating in different depth was observed by scanning election microscope (SEM). The chemical composition of the phase in different depth was measured by energy-dispersive X-ray diffraction machine (XRD).The experimental results showed that there is a diffusive layer between coating and substrate, which has a thickness about 10μm. There was a dispersive process between coating and substrate during the sintering process, which resulted in a firmly metallurgy bond.The HRC hardness of the surface and microhardness in different depth of the coating were measured. It showed that the HRC hardness of the coating was much higher than substrate. In comparison of the microhardness in different depth of the coating, it can be found that diffused layer was the lowest, which of substrate near to diffused layer was a little higher than that before sintering. And the microhardness of the coating was not only much higher than that of substrate, but also evenly distributed.In the wearing test, the wear resistant of the layers in the coating were quite the same except the layer near to the diffused layer, which indicated the worst wear resistant under dry friction condition. Under lubricated condition, the coating showed better wear resistant, the wear volume was hardly observed even the load was 4 times than dry friction condition.