Protective composite coatings obtained by plasma electrolytic oxidation on magnesium alloy MA8

The effect of dispersion and ξ-potential of the nanoparticles (ZrO2 and SiO2) used as an electrolyte component for PEO on the composition and properties of the coatings has been investigated. Improvement of the protective properties for coatings with the incorporated nanoparticles has been explained by the greater thickness of the protective layer, relatively low porosity and the presence of narrow non-through pores. The layer with zirconia has an impedance modulus measured at low frequency (|Z|f→0Hz = 1.8 × 106 Ω cm2) more than one order of magnitude higher than the PEO-coating formed in the electrolyte without nanoparticles (|Z|f→0Hz = 5.4 × 104 Ω cm2).