Study on Surface Modification of Ductile Iron by High-speed Laser Cladding Ni-based Alloy Coating

To improve the surface properties of ductile cast iron, the Ni-based alloy coating was prepared on the surface by high-speed laser cladding technology.The phase, surface hardness, wear resistance and corrosion resistance of the coating were analyzed.The results show that the Ni-based alloy coating is mainly composed of γ-Ni, Cr₂₃C₆, Ni₂Si and Ni₃B phases.The average hardness of the coating surface is approximately 1.58 times than that of ductile cast iron, and the abrasion loss is reduced by 65.7%compared with that of the substrate.The coating is primarily abrasive wear with a small amount of spalling pits, and the substrate is mainly adhesive wear.Compared with ductile cast iron, the self-corrosion potential E_corr of Ni-base coating is increased by 187.1 mV, and the impedance value is greater than that of the substrate at the same frequency, and the corrosion resistance is better than that of ductile cast iron.