Effect of in-situ Ni interlayer on the microstructure and corrosion resistance of underwater wet 316L stainless steel laser cladding layer

Underwater wet laser cladding technology as a new online repair technology, has a wide application prospect in the field of marine engineering. In this work, the underwater wet laser cladding layers of 316L stainless steel with in-situ Ni interlayer on EH40 were successfully manufactured using the underwater wet laser cladding technology. The effect of the in-situ Ni interlayer on the elemental distribution, microhardness, properties and interfacial characteristics of the underwater wet cladding layer was investigated. The in-situ Ni interlayer formed a diffusion buffer between the substrate and cladding layer to mitigate the Fe, Cr and C element diffusion and increased the Ni content in the cladding layer. The addition of the in-situ Ni interlayer promoted the formation of austenite. The wear resistance of the underwater wet laser cladding layer with in-situ Ni interlayer was higher than that of the in-air laser cladding layer, and the main wear mechanism was abrasive wear. In addition, the corrosion resistance of the underwater wet laser cladding layer was improved effectively by applying the in-situ Ni interlayer, and the corrosion resistance basically reached the same level with the in-air laser cladding layer. Thus, the in-situ Ni interlayer has guiding significance for the underwater wet laser cladding technology of Fe-based materials.