| 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 vacuum fusion sinter Ni-base alloy WC composite coating were investigated.The microstructure of the coating in different depth was observed by electron scanning microscope(SEM).The chemical composition of the phase in different depth was measured by energy-dispersive X-ray diffraction machine(EDX).The experimental results showed that there is a diffusive layer between coating and substrate, which has a thickness about 0.2mm and it appears to be a "white bright band". The volume of the element Fe in the coating and the volume of the element Ni in the substrate were increased after sintering, which means there was a dispersive process during the sintering process, which resulted in a firmly metallurgy bond between the coating and substrate.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, substrate near to diffused layer was a little higher and the coating was much higher than diffused layer. The microhardness in the coating was evenly distributed.In the wearing test, the layer near to the surface showed the best wear resistant and the layers in the coating were quite the same and layer near to the diffused layer 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. |
PDF Full Text Request