PreparationSofS0.3C18CrScompositeScoatingsSwithSdifferentSY₂O₃ contentsSonS3Cr14 stainlessSsteelSsubstrateSbySlaserScladdig. The effects of different Y₂O₃ contents on the microstructure, phase composition and hardness of the cladding layer were studied by metallographic microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and microhardness tester. The results show that there are many porous holes in the cladding layer without adding Y₂O₃, and the microstructure of the cladding layer consists of intragranular ferrite, bainite with grain boundary distributed and a small amount of martensite; After adding Y₂O₃, the dendrite length of the cladding layer is reduced and the number decreases, the dendrite tip is passivated and radially coarsening, the length to diameter ratio decreases, meanwhile the pores of the cladding layer decrease, and the cladding layer is purified. The microstructure of the cladding layer is composed of lath martensite and a small amount of bainite in the grain boundary. With the increase of Y₂O₃, the lath martensite is slightly coarsened, the number of bainite decreases obviously, the carbon concentration of bainite carbide increases, and the type of lamellar carbides transforms from low carbon carbide to high carbon carbide. After adding Y2O3, the microhardness of the clad layer is significantly improved,; When added 2% Y₂O₃, the hardening effect of the cladding layer comes up to the best, which was 160 HV0.2 higher than that without adding Y₂O₃.