Plasma electrolytic oxidation coating of synthetic Al-Mg binary alloys

►The average thickness of PEO coating of Al-Mg alloys increases with Mg content. ►The addition of Mg reduces and prevents the formation of α-Al2O3 and mullite. ►The surface roughness increases with Mg content in the Al-Mg alloys. ►The hardness values of the coating decreases with the Mg amount in the substrate. ►The Mg concentration is constant throughout the main regions of coating.