Preparation and corrosion behavior of MAO based MOFs coatings with excellent film-forming and adhesion properties

Magnesium (Mg) alloys can be applied in many fields, but their poor corrosion resistance limits their widespread applications. Metal-organic frameworks (MOFs) are often used as fillers in the field of corrosion protection due to their poor adhesion. In order to improve the film-forming performance and adhesion of MOFs coatings, and enhance the corrosion resistance of AZ31 Mg alloys, various MOFs coatings were prepared on the Mg alloy micro-arc oxidation (MAO) coating. The results demonstrated that the MAO facilitated film-forming of MOFs and enhanced their adhesion. Moreover, MOFs crystals can seal the pores of MAO, capture corrosive ions, and form insoluble chelates, significantly improving the corrosion resistance of Mg alloys. Among them, the Ce-MOF exhibited the highest corrosion resistance and the lowest corrosion rate, with a corrosion current density of 8.68 × 10−8 A/cm2 after immersing for 30 min. Moreover, MOFs coatings exhibited good stability and durability, and even after immersing in 3.5 wt% NaCl solution for 14 days, their corrosion protection effects were still superior than MAO.