Effect of NiSO ₄ on characteristics of micro‐arc oxidation coating formed on TB9 titanium alloy

Abstract In order to study the effect of NiSO 4 addition on the characteristics of TB9 titanium alloy MAO coating and erosion characteristics, different concentrations of NiSO 4 were added to the electrolyte for MAO treatment. Scanning electron microscope, x‐ray diffractometer, x‐ray photoelectron spectroscopy, electrochemical workstation, and corrosion device were used to study the effect of NiSO 4 addition on the morphology, phase composition, corrosion resistance, and erosion characteristics of TB9 titanium alloy MAO coating. The results show that with the increase of NiSO 4 addition, the oxidation voltage increases, the surface morphology is uniform and dense, and the thickness, hardness, and wear resistance of the coating are improved. The phase of the MAO coating is mainly composed of anatase, rutile, Ti x O, and SiO 2 . The self‐corrosion current and corrosion rate of the MAO coating decreased significantly after the addition of NiSO 4 , and the corrosion resistance was improved. The results of the erosion corrosion experiment show that the 1 g/L NiSO 4 ‐modified ceramic coating can provide effective protection for the titanium alloy substrate. The comprehensive performance of the coating is best when the amount of NiSO 4 added is 1 g/L.