Improvement to corrosion resistance of MAO coated 2519 aluminum alloy by formation of polypropylene film on its surface

In order to improve the corrosion resistance of micro arc oxidized coating on 2519 aluminum alloy, a thin layer of polypropylene (PP) film was prepared on its surface. The structure and corrosion protection properties of the coatings were investigated. The corrosion resistance of micro-arc oxidation (MAO) coating can be improved effectively by forming of this kind of thin film due to the physical barrier effect of PP film and the sealing effect of the micro defects in MAO coating by PP. PP film on MAO coating is deteriorated by micro cracks during immersion. The EIS plots were fitted by appropriate equivalent circuits.