One-step preparation of TiO2/MoS2 composite coating on Ti6Al4V alloy by plasma electrolytic oxidation and its tribological properties

A MoS2-containing oxide coating on Ti6Al4V alloy was prepared by one-step plasma electrolytic oxidation (PEO) process in a MoS2-dispersed phosphate electrolyte. The composition and microstructure of the oxide coatings produced in the electrolytes with and without the addition of MoS2 were analyzed by X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). Results showed that the MoS2 particles can be successfully incorporated into the oxide coating during the PEO process and were preferentially located in the micropores. The ball-on-disk sliding tests indicated that MoS2-containing oxide coating registered much lower friction coefficient and wear rate than the oxide coating without MoS2 under dry sliding condition. The improved tribological property of the MoS2-containing oxide coating was also discussed.