Corrosion resistance and antibacterial properties of hydrophobic modified Ce-doped micro-arc oxidation coating

Abstract

Aluminium (Al) alloys with high corrosion resistance and bactericidal capability will have significant potential for broader utilization in marine applications. To achieve this, a layer of cerium (Ce)-doped anodic oxidation (AO) film was prepared on the surface of the Al alloy to modify the pore structure of the micro-arc oxidation (MAO) coating. This not only improved its corrosion resistance but also imparted certain antibacterial properties to the coating. Then, 1H, 1H, 2H, 2H- perfluoroalkyltriethyloxy-silane (PFOTES) was used to hydrophobically modify the coating, which more effectively obstructed corrosive ions and bacteria, further elevating its corrosion resistance and antibacterial properties. Electrochemical tests demonstrated that |Z|0.01Hz of the modified coating was 2.86 × 109 Ω·cm2 which was two orders of magnitude higher than before. Furthermore, it remained above 109 Ω·cm2 even after 288 h of immersion. Moreover, the antibacterial effectiveness of the modified coating against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) increased by 5.89% and 19.53%, respectively, to 98.58% and 97.34%. These findings indicate a promising direction for improving the corrosion resistance of MAO coatings on metallic materials, paving the way for large-scale industrialization.