Preparation And Properties Of ZrB₂-SiC/Cu Composite Coating By Laser Cladding

Copper and copper alloy materials have good electrical conductivity and thermal conductivity,so it has a wide range of applications.But its hardness is relatively low,wear resistance is not good.How to improve the wear resistance and does not reduce its excellent characteristics is the research point now.The laser cladding technology has a lot of advantages,its small distortion to the substrate and easy control of the energy input.So laser cladding technology is used to improve the wear of the copper in this study.In this paper,Zr,Si,B4 C,and electrolytic copper powder were mixed in a certain proportion.The surface of pure copper was clad by the synchronous powder feeding to make ZrB₂-SiC/Cu composite coating.The properties of the composite coatings has been studied,and the optimized parameters of energy density and phase content were selected.The microstructure of the composite coatings was observed by OM and SEM.The bonding between the coatings and the matrix was analyzed.The phases in the composite coatings were determined by XRD,and the coating was further analyzed by TEM.Finally,the wear resistance of the composite coatings was characterized by current-carrying friction and wear tests.The results show that the composite coating has excellent mechanical properties when the power density is 60.00kJ/cm²,the content of the reinforcing phase is 20 wt.%.The conductivity was maintained at 13.5%IACS and the tensile strength was 330 MPa.In the composite coating,the distribution of the enhanced phase showed a gradient distribution.There were morphological differences in the depth direction of the coating,and the bond between the reinforcement phase and the matrix was good.At the same time,other phases were found inside the composite coating,Cu51Zr14,Cu3.8Ni and Ni3 Si.These new phases were detected in the XRD,indicating that these phases are relatively low,and the distribution is not uniform,The existence of these phases also played a role in enhancing the composite coating.Friction and wear tests show that the wear rate of the composite coating is relatively low,the composite coating has excellent wear resistance and anti-current ablation capacity.The wear resistance of the composite coatings increases with the content of the reinforcement phase in the coatings.Low content is the corresponding wear mechanism for the adhesive wear,high content for the abrasive wear.The wear rate of the coatings increases with the sliding speed and load.With the current condition the wear of the coating is greater than without current condition.