Corrosion failure process of organic conductive coating on Mg-RE alloy with PEO in the simulated Xisha atmospheric solution

Organic conductive coating/plasma electrolytic oxidation (PEO) coating/Mg-RE alloy is a simple way to meet the functional requirements and service safety of electronic equipment. In this work, the Macro electrochemistry, micro electrochemistry and mechanical test were performed to study the corrosion failure process of organic conductive coatings and PEO coating on the surface of Mg-RE alloy under the harsh marine atmospheric environment. Organic conductive coatings have protective effect on Mg-RE with PEO coating (the impedance modulus remain higher than 10 6 at low frequencies during 21d immersion, and the characteristics of EIS remained constant). But local failure of bonding between organic conductive coating and PEO coating were occurred after being immersed in Xisha simulation solution and it weakened the long-term protection ability of organic conductive coating/PEO coating/Mg-RE alloy system, which limited long-term corrosion resistance. • Corrosion failure process of organic conductive coatings on Mg-RE alloy were studied. • The characteristic of corrosion failure process of coatings had been recorded. • Both organic conductive coatings have protective effort for Mg-RE with PEO coating. • Local failure of bonding was the main reason of corrosion failure.