Effect of composite PEO film containing titanium oxides on the corrosion resistance of Al 6061 alloy

Composite plasma electrolytic oxidation (PEO) was carried out to deposit Ti-oxides directly on a substrate of Al 6061 alloy. A TiO2 (anatase)- and Al2O3-dense composite PEO film is generated on the substrate, and the corrosion resistance was examined by electrochemical analyses: potentio-dynamic polarization (PP), and electrochemical impedance spectroscopy (EIS) using an equivalent electrical circuit model. In addition, surface and cross-sectional morphologies were observed to confirm the dependence of pore size on treatment time. Using a current density of 10 A/dm2 applied for up to 30 min, the PEO film produced is denser, more continuous, and has smaller pores in comparison to conventional PEO specimens. In addition, the corrosion resistance observed in the electrochemical tests is enhanced for the composite PEO film in comparison to conventional PEO treatment.