PEO coating with Ce-sealing for corrosion protection of LPSO Mg-Y-Zn alloy

Plasma Electrolytic Oxidation coatings (PEO), without and with Ce-based sealings, were developed on a Mg-Y-Zn alloy containing long period stacking order (LPSO) phases in order to improve its corrosion behaviour. Specimens were investigated in terms of morphology, composition and corrosion behaviour (polarization and hydrogen evolution measurements). PEO improved the corrosion resistance compared to the bulk material. Sealing for 5 min plugged the coating pores and cracks with Ce-rich compounds, resulting in improved long-term corrosion behaviour. Sealing for 1 h resulted in excessive dissolution of the coating and deterioration of the inner barrier layer.