Study on the modification of TC11 titanium alloy microarc oxidized film layer by ZrO2 particles

To enhance the service safety of the TC11 titanium alloy, a critical material in the aerospace field, this study utilizes the incorporation of particles into the coating to repair pores and other defects, thereby improving its wear and corrosion resistance. In this paper, ZrO2 particles were added to the base electrolyte at different concentrations. The surface morphology, phase composition, hardness, friction and wear behavior, and corrosion resistance of the coatings were characterized using SEM, XRD, a multifunctional tribometer, a white light interferometer, and an electrochemical workstation. The results show that with the increase of the content of ZrO2, the size of the holes on the surface of the coating, the porosity, and the surface roughness all first decrease and then increase. The minimum porosity of the coating is 7.9%. The maximum thickness of the coating is 18.4 μm, representing an increase of 93.7%. After adding ZrO2, the main phase composition of the coating consists of Ti, rutile-type TiO2 (rutile), anatase-type TiO2 (anatase), ZrO2, and ZrTiO4. And as the content of ZrO2 increases, the intensities of the diffraction peaks of ZrO2 and ZrTiO4 also increase. The maximum hardness of the coating is 912 HV, showing an increase of 32.9%. After adding ZrO2, the friction coefficient of the coating can be reduced to about 0.25 when the content of ZrO2 is 8 g/l at the lowest, and the minimum wear volume is 0.837 mm3 when the content of ZrO2 is 8 g/l. This is because the addition of ZrO2 particles can promote the transformation from the anatase phase to the rutile phase. The presence of the hard phase rutile-type TiO2 enhances the resistance of the coating to the external environment and also improves the corrosion resistance of the coating. The effect of 8 g/l ZrO2 particles is the best, with a self-corrosion potential of −0.3126 V and a corrosion current of 7.45 × 10−9 A/cm2. The optimal coating performance is achieved when the ZrO2 content is 8 g/l.