The effect of plasma electrolytic oxidation process parameters on the tribocorrosion properties of TiO2 coatings

Despite the fact that Titanium and its alloys are materials which have excellent corrosion-resistant properties, they have poor wear and friction performance under tribological conditions. The aim of this study is to find suitable parameters for the surface treatment of Cp-Ti substrates which are used under saline environment. In this study, TiO2 coatings were grown on Cp-Ti substrates at different frequencies which are parameters of the coating process. Due to its low cost and ability to achieve high thicknesses, The Plasma Electrolytic Oxidation (PEO) method was applied to grow TiO2 coatings. The microstructures, morphology, and crystallographic structure were analyzed using SEM and XRD. Tribocorrosion properties of the coatings were investigated using a combination of the pin-on-disk wear test and potentiodynamic polarization test units. The frequency is known to have a strong impact on the PEO process. The impacts of frequency changes on the PEO coating performance were examined under a constant voltage. As result, the increase of the frequency caused smaller pores and cracks in the surface morphology of the coating and at the same time this yielded an increment on the tribocorrosion behavior of the coating.