Effect of Rare-Earth La2O3 on Tribological Properties of Laser Cladding Nickel-Based Coatings on 35CrMoV Alloy Steel

The Ni60 alloy cladding layer with different La2O3 content was prepared by laser cladding technology on 35CrMoV surface. The phase composition, element distribution, micro-structure and tribological properties of the coating with different addition of La2O3 were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), Microscopic Vickers hardness tester, MicroXAM-800 optical surface photometer and friction testing machine. The results show that the main phases of the cladding layer are (Ni, Fe), CrB, CrMn, Cr7C3 and Cr23C6. The diffraction peak shifted to the left in XRD with the addition of La2O3, which indicates that there is a certain lattice distortion in the cladding phase. The microstructure of the cladding layer is refined, the friction coefficient and the depth of wear trace are decreased to varying degrees, and the wear resistance of the cladding layer is greatly improved. The results show that the addition of 1.6%La2O3 can effectively refine grain, inhibit the formation of cracks and pores, and improve the wear performance of the cladding layer.