A hierarchically structured coating on 2A12-T4 aluminum alloy for anti-wear and corrosion

2A12-T4 was micro-arc oxidized (MAOed) in silicate and phosphate mixed electrolytes and then sealed with polytetrafluoroethylene (PTFE) to improve the wear and corrosion resistance. The optimized MAOed coating was well adhered and consisted of gradient-nanostructured γ-Al2O3 and mullite. It decreased icorr by 3 orders of magnitude lower than bare substrate. After sealing and/or hydrothermally aging treatment, the coating had obviously increased anti-wear and corrosion performance due to the decreased micropores/cracks and improved PTFE adhesion. This work provides an outstanding coating on 2A12-T4 for anti-wear and corrosion simultaneously and it should be self-enhanced in performance even if serves with hot steam.