An Investigation of the Surface Quality and Corrosion Resistance of Laser Remelted and Extreme High-Speed Laser Cladded Ni-based Alloy Coating

Ni-based coatings are prepared on 2Cr13 steel substrate by extreme high-speed laser cladding and subsequent laser remelting (EHLA-LR). The effects of laser remelting (LR) treatment on the morphology, microstructure, residual stress and corrosion resistance of extreme high-speed laser cladded (EHLA) coatings are investigated in details. The results demonstrate that the integrated EHLA-LR process could dramatically reduce the surface roughness by 86%, improve the surface compactness and optimize the surface flatness. The dendrite spacing in the near surface region of the coating via EHLA-LR decreases with refined grains, while the phases of the coatings change little in spite of LR treatment. It was found that the residual compressive stress of the coatings is maintained, but it is slightly reduced upon LR. Furthermore the coatings via EHLA-LR possess better corrosion resistance than that of coatings via EHLA owing to the increased surface compactness and grain refinement by LR process.