Production of Porous ZrO2–TiO2 Ceramic Coatings on the Biomedical Ti-6Al-4V Alloy via AC PEO Treatment and Their Effects on the Corrosion Behavior in 0.9% NaCl

Ti and its alloys have been vastly employed in the manufacturing of biomedical implants for orthopedy and dentistry, especially the Ti-6Al-4V alloy (wt%), which is the most-used Ti alloy worldwide. However, the ion release of Al and V in the long term has been related to harmful effects on the human body. In this scenario, surface modification strategies, such as plasma electrolytic oxidation (PEO), have often been performed in Ti alloys to match the clinical needs. This study evaluated the effect of electrical AC parameters on the surface of the commercial Ti-6Al-4V alloy immersed in ZrO2-rich electrolytic solution regarding the chemical, physical, structural, and topographical aspects. Then, the selected PEO-treated samples surpassed the electrochemical test in saline solution. The results indicated that the electrical AC parameters affect the duration and intensity of the oxidative reactions and plasma micro-discharge steps, resulting in porous and thick oxide layers. PEO treatment promoted bio-camouflage of the surface, enriching it with TiO2, ZrO2, and ZrTiO4 compounds and depleting it of Al and V. After screening the PEO-treated samples and their corrosion behavior, the results indicated that the porous ZrO2–TiO2 ceramic coatings in the Ti-6Al-4V alloy can be a viable alternative for the manufacturing of biomedical implants.