Effect of La2O3 on microstructure, mechanical and tribological properties of Ni-W coatings

In this paper, a Ni-W-La₂O₃ composite coating was prepared by the electrodeposition method. Micro-hardness tester and environmental scanning electron microscope equipped energy dispersive spec-troscopy were employed to investigate the microhardness and the surface morphology of the com-posite coatings respectively, and the high temperature friction behavior and corrosion resistance of the coatings against molten glass were investigated by using a high temperature tribometer. The results show that La₂O₃ can refine the microstructure effectively, and make the element distribution uniform, which leads to the increase of average microhardness. La₂O₃ particulates can reduce the friction coef-ficient between the composite coating and glass during the sliding process at about 973 K largely, and the corrosion resistance of the La₂O₃ added Ni-W coatings is effectively improved compared with that of the non-added one, furthermore the mechanism of friction-reducing and anti-corrosion is also dis-cussed.