Microstructure and wear resistance of TiB₂/Ni composite coating on pure copper surface by argon arc cladding

The TiB₂ reinforced Ni-based composite coating is prepared on the surface of pure copper by argon arc cladding technology to improve its wear resistance. The Ti powder, B powder and Ni powder are ball-milled and mixed. The ceramic particle reinforced nickel base coating was fabricated by melting the preset powder on the surface of pure copper by using argon arc cladding. The phase of the coating and the composition, distribution and structure of ceramic particles in the coating were analyzed by X-ray diffractometer, scanning electron microscope and transmission electron microscope. The microhardness and wear properties of the coating were tested by microhardness tester and friction and wear tester. The results showed that the phases of the cladding coating mainly include γ (Ni, Cu) and TiB₂. The ceramic particle reinforced phases are uniformly dispersed in the cladding coating. However, the particle phase TiB₂ exists in the form of hexagon. There is no defect in the interface between cladding layer and substrate. The cladding coating has high microhardness. When the mass fraction of (Ti+B) is 10%, the microhardness of the coating is as high as 781.3 HV. Compared with the pure copper substrate, the microhardness of the cladding coating is increased by about 11.7 times. With the increase of (Ti+B) mass fraction, the friction coefficient and wear loss of the coating decrease first and then increase under the same wear conditions, respectively. The in-situ synthesized TiB₂ particles reinforced nickel base coating can significantly improve the wear resistance of the pure copper surface by argon arc cladding technology.