Low Frictional TiO<sub>2</sub> and MoS<sub>2</sub>/TiO<sub>2</sub> Coatings on Ti-6Al-4V Alloy

TiO2 and MoS2/TiO2 coatings were prepared using a Plasma Electrolytic Oxidation (PEO) process at a unipolar pulsed-DC mode. Both coatings, mainly comprised of anatase TiO2, exhibited a low coefficient of friction, C.O.F < 0.21 for the TiO2 coating and C.O.F < 0.16 for the MoS2/TiO2 coating, while the MoS2/TiO2 coating had a longer wear life than TiO2-coated and uncoated Ti alloy (Ti-6Al-4V). This result showed that the solid lubricant MoS2 may play a significant role in the tribological behavior and it can be applied to many high load-bearing systems in aerospace and automotive industries.