Effect of electrolyte composition on corrosion behavior and tribological performance of plasma electrolytic oxidized TC4 alloy

Four kinds of typical plasma electrolytic oxidation (PEO) coatings were prepared on TC4 alloy to investigate the influence of electrolyte composition on the corrosion behavior and tribological performance of the PEO coatings. The results show that both the corrosion behavior and tribological performance of the PEO coatings are highly dependent on the electrolyte composition. The PEO coating fabricated from the electrolyte containing NaH2PO2 exhibits the best corrosion resistance owing to its denser inner layer. The PEO coating prepared from the electrolyte containing NaAlO2 reveals the best tribological performance due to the generation of Al2O3. To prepare a PEO coating with satisfying corrosion resistance and wear resistance, a composite PEO coating was fabricated from the electrolyte containing NaH2PO2 and NaAlO2.