Effect of CeO₂ on microstructure and properties of Ni60 alloy coating by laser cladding

In order to study effect of rare earth element CeO₂ on laser cladding coatings, cladding layers with different contents of rare earth oxides were prepared by laser cladding overlap processing, using 45^# steel as substrate, Ni60 and Ni60+CeO₂ powder as cladding material. Through experiments of cladding layer dye test, microstructure observation, and microhardness mensuration, effect of different contents of rare earth oxides on cladding layer surface cracks' number, microstructure, and hardness was analyzed. The results show that the optimal doping mass fraction of CeO₂ is 0.004. The crack number of the cladding coating is reduced and the micro structure of the cladding layer is even and tiny with the doping of rare earth element CeO₂. The microhardness of the cladding coating surface is much higher than that of the matrix. The Vivtorinox hardness is 3.6 times of that of the matrix. The hardness of the lapping zone is about 3 times of that of the matrix. The addition of rare earth element can restrain the crack, refine the grain and improve the hardness of cladding layer to some extent.