Effect of Oxide Film on Corrosion Behavior of NiTi Coating Prepared by Extreme High-Speed Laser Cladding

NiTi alloy has excellent corrosion resistance and wear resistance, and is an important protective coating being developed for marine equipment. In this paper, the crack and pore-free high-quality NiTi coatings were firstly synthesized in situ by extreme high-speed laser cladding (EHLA) technology under high temperature oxidation environment. The effects of laser power of EHLA on the temperature field, stress field and coating properties of NiTi coatings were studied by combining finite element calculation and experiments. The results show that a corrosion-resistant and wear-resistant TiO2 oxide film was generated in situ on the coating surface during EHLA process. Furthermore, the denser oxide film can be obtained by proper annealing treatment, and the wear resistance and corrosion resistance of the sample can be further improved. This provides a feasible fashion for EHLA to in situ synthesize wear-resistant and corrosion-resistant alloy coatings with low defects.