Effect of Ni on microstructure and properties of CuSn10 coating on 42CrMo steel by laser cladding

Copper-tin alloys possess outstanding casting performance and wear resistance, and are mainly employed in the manufacturing of wear-resistant components under high load and high sliding velocity. To improve the strength of the CuSn10 cladding coating, the influence of Ni on the microstructure, microhardness, and tribological properties of the copper tin alloy was investigated. Four CuSn10 coatings with different Ni contents were fabricated on the 42CrMo steel by laser cladding technology. A corresponding numerical model was established by means of Ansys Workbench, and the optimum experimental parameters of the laser cladding process were derived. The simulation results indicate that when the laser power is 3,000 W, the scanning speed is 15 mm·s −1 , and the powder feeding rate is 3.5 r·min −1 , the CuSn10 coating with the best cladding effect can be obtained. X-ray flaw detection tests were conducted on the coatings, and the results indicate that the S3 coating (10wt.% Ni) exhibits the best cladding quality and the fewest defects. XRD diffraction analysis demonstrates that the coating is mainly composed of Cu, Cu 13.7 Sn, and Cu 41 Sn 11 . This is supported by SEM electron microscopy and EDS quantitative analysis results. The function of Ni is mainly reflected in grain refinement and enhancement of element diffusion. Meanwhile, microhardness test and friction and wear experiment were conducted on the coatings. The experimental results demonstrate that the addition of Ni enhances the hardness and friction performance of the CuSn10 coating. The average microhardness of the S4 coating (15wt.% Ni) is the highest, which is 1.36 times as that of the CuSn10 coating. The S4 coating exhibits a wear rate of 1.96×10 −4 mm 3 ·N −1 ·m, which is 23.7% lower than that of the CuSn10 coating, demonstrating the best anti-wear ability. SEM observation of the wear scars reveals that the wear mechanisms vary with Ni content: abrasive and oxidative wear dominate in S1–S3, whereas S4 (15wt.% Ni) is mainly governed by adhesive wear with localized oxidation.