Effect of La_2O_3 on Microstructure of Laser Cladding Ferrite-based Alloy Coatings

After adding different contents of La_2O_3,the ferrite-based alloy coatings on the substrate of 16Mn steel were cladded by a CO_2 laser with automatic powder feeding system.The microstructure and elements distribution of the coatings were investigated by scanning electron microscope (SEM) and energy-dispersive analysis of X-rays (EDAX).The phase structure and microhardness of the coatings were measured by X-ray diffraction (XRD) analysis and microhardness tester respectively,the effect of La_2O_3 on the inclusion of the coatings was also studied.The results showed that the main phase of the coating was γ(Fe,Ni).With the addition of La_2O_3,the microstructure of the coatings was refined and purified,the microhardness was increased.Moreover,the microstructure was uniform.