Dual Antifouling Mechanisms Induced by Cupric Ions and Needle-Like Alumina in Arc-Sprayed Composite Coatings

Aluminium-polymethyl methacrylate-copper (Al-PMMA-Cu) composite coatings were developed using cored wire arc spraying. The bacteria Bacillus sp. was used to evaluate the antifouling performances of the coatings. The microstructures and antifouling mechanisms of the coatings were investigated and discussed. The results show that the composite coatings presented improved antifouling performances, and two antifouling mechanisms were explored. On the one hand, the Cu nano-particles were released to seawater due to corrosion of the Al components, converted to cupric ions, and killed the bacteria. Meanwhile, oxidation of Al was accelerated due to Cu-Al galvanic reaction, and the needle-like corrosion products were formed, which pierced the cell membranes and killed the bacteria. The effects of the PMMA on the electrochemical properties of the coatings were also evaluated. The results show that the sealing function of the PMMA components enhanced the corrosion resistance of the Al-PMMA-Cu coatings. This investigation shed light on one-step construction of antifouling and anticorrosion layers for marine applications.