The interaction mechanism of cavitation erosion and corrosion on HVOF sprayed NiCrWMoCuCBFe coating in artificial seawater

When flow passage components were used in the ocean, it was inevitable that they could be damaged by the coupling effect of cavitation erosion and corrosion. It is necessary to explore the interaction mechanism between cavitation erosion and corrosion of the protective coating in marine. In this study, NiCrWMoCuCBFe coating was prepared on 316L stainless steel by high velocity oxy fuel (HVOF) spraying technique. The microstructures and three-dimensional morphologies of coatings were observed. And its cavitation erosion resistance was evaluated by means of a vibratory apparatus in artificial seawater. The influence of corrosion on cavitation erosion of NiCrWMoCuCBFe coating was also investigated. In addition, an electrochemical workstation equipped with a three-electrode system was used to measure the electrochemical properties of this coating after different time cavitation erosion, revealing the effect of cavitation erosion on corrosion. Results show that with the increase of cavitation erosion time of NiCrWMoCuCBFe coating in artificial seawater, many particles with nanometer sizes of NiO, Cr2O3, MoO3 and Mo2C were generated on the cavitation erosion region of coatings because of the coupling effect of corrosion and cavitation erosion, which played an important role on slowing down the rate of cavitation erosion and improving corrosion resistance.