Investigation of the voltage and time effects on the formation of hydroxyapatite-containing titania prepared by plasma electrolytic oxidation on Ti-6Al-4V alloy and its corrosion behavior

► Formation of HA/TiO2 coating on Ti-6Al-4V alloy may improve the corrosion behavior. ► Effect of voltage and time on PEO process for HA formation was investigated. ► For formation of HA phase with titania a voltage of 500 V is needed. ► At 500 V, the amount of HA phase increased with increasing the treatment time. ► The best corrosion behavior was observed for the sample coated at 500 V and 15 min.