Stainless steel powders with different molybdenum (Mo) contents were deposited on the substrate surface of 45 steel using a 6 kW fiber laser. The microstructure, phase, microhardness, wear properties, and corrosion resistance of coatings with different Mo contents were studied by scanning electron microscopy (SEM), electron probe microanalyzer (EPMA), X-ray diffraction (XRD), microhardness tester, wear tester, and electrochemical techniques. The results show that good metallurgical bonding was achieved between the stainless steel coating and the substrate. The amount of M₇(C, B)₃ type borocarbide decreases and that of M₂B and M₂₃(C, B)₆ type borocarbides increases with the increase of Mo content in the coatings. The amount of martensite decreases, while the amount of ferrite gradually increases with the increase of Mo content. When the Mo content is 4.0 wt. %, Mo₂C phase appears in the coating. The microstructure of the coating containing Mo is finer than that of the Mo-free coating. The microhardness decreases and the wear resistance of the coating gradually improves with the increase of Mo content. The wear resistance of the 6.0 wt. % Mo coating is about 3.7 times that of the Mo-free coating. With the increase of Mo content, the corrosion resistance of the coating firstly increases and then decreases. When the Mo content is 2.0 wt. %, the coating has the best corrosion resistance.

Ni-based alloy powders with different contents of cobalt (Co) have been deposited on a 42CrMo steel substrate surface using a fiber laser. The effects of Co content on the microstructure, composition, hardness, and wear properties of the claddings were studied by scanning electron microscopy (SEM), an electron probe microanalyzer (EPMA), X-ray diffraction (XRD), a hardness tester, and a wear tester. The results show that the phases in the cladding layers are mainly γ, M₇(C, B)₃, M₂₃(C, B)₆, and M₂B. With the increase in Co content, the amounts of M₇(C, B)₃, M₂₃(C, B)₆, and M₂B gradually decrease, and the width of the eutectic structure in the cladding layer also gradually decreases. The microhardness decreases but the wear resistance of the cladding layer gradually improves with the increase of Co content. The wear resistance of the NiCo30 cladding layer is 3.6 times that of the NiCo00 cladding layer. With the increase of Co content, the wear mechanism of the cladding layer is changed from abrasive wear to adhesive wear.