TiO₂ Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

Abstract

Plasma electrolytic oxidation (PEO) has been used in the past as a useful surface treatment technique to improve the anticorrosion properties of Mg alloys by forming protective layer. Coatings were prepared on AZ31 magnesium alloy in phosphate electrolyte with the addition of TiO 2 nanoparticles using plasma electrolytic oxidation (PEO). This present work focuses on developing a TiO 2 functional coating to create a novel electrophotocatalyst while observing the surface morphology, structure, composition, and corrosion resistance of the PEO coating. Microstructural characterization of the coating was investigated by X‐ray diffraction (XRD) and scanning electron microscopy (SEM) followed by image analysis and energy dispersive spectroscopy (EDX). The corrosion resistance of the PEO treated samples was evaluated with electrochemical impedance spectroscopy (EIS) and DC polarization tests in 3.5 wt.% NaCl. The XRD pattern shows that the components of the oxide film include Mg from the substrate as well as MgO and Mg 2 TiO 4 due to the TiO 2 nanoparticle addition. The results show that the PEO coating with TiO 2 nanoparticles did improve the corrosion resistance when compared to the AZ31 substrate alloy.