Synthesis of composite coatings based on Mg and Ti oxides by PEO for modulation of Mg corrosion resistance

In this study, the application of Plasma Electrolytic Oxidation (PEO) technique was investigated for fabricating composite coatings on magnesium (Mg) substrates aimed at modulating their corrosion resistance, an important characteristic for biodegradable orthopedic implants. The coatings were manufactured using an electrolytic solution containing MgO and TiO2 oxides, varying mass ratios, at currents of 30 mA and 200 mA. X-ray diffraction patterns confirmed the presence of TiO2 and MgO phases in the coatings, demonstrating the PEO capability to modulate the chemical composition by adjusting the mass ratio of oxides in the electrolytic solution. Microstructural analysis revealed decreased surface roughness with increasing TiO2 concentration. Corrosion tests indicated a significant improvement in corrosion resistance for all coatings compared to uncoated Mg substrate. In particularly, coatings with higher TiO2 concentrations, and those applied at a current density of 30 mA exhibited, enhanced corrosion resistance.