Enhanced wear resistance of CuSn19Ti10/Ni-coated diamond composite coatings prepared by laser cladding: Influence of nickel plating on diamond retention and microstructure

Abstract

This study investigated the effects of nickel (Ni) coating on diamond particles in CuSn19Ti10/diamond composite coatings fabricated on pure copper substrates using laser cladding. Prior research emphasized that diamond retention is key to improving the wear resistance of these coatings. Here, Ni-coated diamond particles were incorporated to enhance bonding. The composite coatings, containing 2.5, 5, and 10 wt% of Ni-coated diamond, were systematically characterized through scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and wear testing. The microstructural analysis revealed the presence of α-(Cu), Cu₂SnTi, (Cu,Sn)Ti_x, TiC, and diamond phases. Compared to uncoated diamond composite coatings, the Ni-coated diamond composite coatings demonstrated significantly improved wear resistance, with wear rates reduced by 8.54 %, 15.52 %, and 85.44 %, for 2.5, 5, and 10 wt% Ni-coated diamond, respectively. The enhancement in performance can be attributed to the laser's high temperature, which allowed the Ni dissolution within the metal matrix to facilitate the diffusion between Ti and C, enhancing the Ni-coated diamond's retention capacity in the metal matrix. The Ni-coated diamonds were more firmly retained in the matrix during wear, reducing pull-out and enhancing the overall wear resistance of the coating. The findings suggest that Ni-coating on the surface of diamonds is an effective strategy for improving the wear resistance of diamond-reinforced metal matrix composite coatings.