Preparation and Properties of MAO Self-Healing Anticorrosion Film on 5B70 Al Alloy

Micro-arc oxidation (MAO) was a new surface treatment technology for Al alloys. However, the MAO ceramic film could not provide long-term protective performance owing to its inherent porous structure. In this work, a new type of CeO2-sealed GO/Al2O3 composite film on 5B70 Al alloy with excellent corrosion resistance was prepared by integrating MAO and the hole sealing technique. The experimental results indicated that the loose and porous MAO ceramic film could serve as a 'shield' and a 'reservoir', respectively, to obtain improved impedance and sufficient corrosion inhibitor loading. Compared to the original MAO ceramic film or GO/Al2O3 composite film, The GO/Al2O3 composite film after sealing treatment for 60 min had lower porosity and better corrosion resistance. In addition, CeO2-sealed GO/Al2O3 composite film exhibited a positive self-healing effect in 3.5 wt% NaCl solution.