Effect of the Laser Remelting Power on the Wear Resistance of the WC-Ni Coatings Sprayed by HVOF
In order to investigate the effect of microstructural changes on the hardness and wear resistance of coatings,low-cost high-velocity oxygen-fuel spraying(HVOF)technology was used to pre-deposit WC-Ni coatings,and the coatings were treated by laser remelting at a power of 50～150 W.The influence of laser remelting power on the microstructure,phase composition,microhardness and wear resistance of WC-Ni coatings was studied.Results showed that after remelted by 150 W laser,the WC in the coating formed a honeycomb like skeleton structure,enhancing the toughness of the material and significantly suppressing the generation and propagation of cracks.When the laser power was low(50 W and 100 W),no honeycomb like skeleton structure was observed in the coating.However,due to the thermal effect of the laser,the co-hesion between the flat particles in the original coating was enhanced,and the hardness and wear resistance were improved to some extent.The average hardness of the original WC-Ni coating was 327 HV02,while the hardness of the coatings after 50 W and 100 W treatment increased to 335 HV02 and 346 HV02,respectively.Moreover,after 150 W treatment,a uniform honeycomb like WC skeleton structure was formed in the coating,and some WC and Ni formed Ni4W,thereby reducing slightly the hardness of the coating after 150 W treatment(288 HV02).The WC in the coating treated with 150 W evolved into a mesh like skeleton structure,which could effectively suppress the formation and propaga-tion of cracks,and the wear rate was the lowest,only 3.544×10-5 mm3/(N·m),This represented a reduction of 83.9％,75.1％,and 68.7％compared to the wear rates of the original WC-Ni coating[2.025 × 10-4 mm3/(N·m)]and coatings subjected to 50 W[1.424× 10-4 mm3/(N·m)]and 100 W[1.132×10-4 mm3/(N·m)]laser remelting,respectively.Overall,the WC-Ni coatings with honeycomb structure could provide a new approach for the development of wear-resistant materials.
laser surface remeltinghigh-velocity oxygen-fuelmetal ceramic coatinghoneycomb structurefriction and wear
万方数据
维普
