Study on the effect of LuCl3 doping on the characteristics of titanium alloy micro-arc oxidation coatings

The micro-arc oxidation of TC4 titanium alloy was carried out by adding LuCl3. The effect of LuCl3 addition on the properties of the micro-arc oxidized coatings, and the rate of weight loss by erosion under simulated oil field conditions, were analysed. The results show that the increase of oxidation voltage after the addition of LuCl3 makes the surface structure of the coatings denser. The coating is mainly composed of Rutile TiO2, Anatase TiO2, and a small amount of Lu2O3 phase. The kinetic potential polarization curves showed that the addition of LuCl3 can increase the corrosion potential and decrease the corrosion current density of TC4 titanium alloy, and at the same time reduce the rate of erosion weight loss of micro-arc oxidized coatings under simulated oilfield conditions. The overall performance of the coatings is best when the concentration of LuCl3 is 0.3 g L−1.