Cored-wire arc spray fabrication of novel aluminium-copper coatings for anti-corrosion/fouling hybrid performances

The booming ocean economy in recent decades crucially demands advanced anti-corrosion technologies for marine infrastructures. Among the marine protective coatings developed in past decades, thermal sprayed aluminium coating was evidenced to be one of the most economical and efficient corrosion protection layers. Yet, marine corrosion is always accompanied by biofouling which in most cases accelerates corrosion. Here we report arc spray fabrication of novel aluminium-copper coatings using home-made Al-Cu cored wires for both anti-corrosion and antifouling performances. Copper particles were dispersed in the as-sprayed coatings, and TEM characterization further revealed partial interaction of Cu particles with Al matrix during the coating deposition. The chemical reaction with the formation of Al2Cu offered an anchoring effect for the coatings preventing Cu particles from quick releasing into aqueous environment. Electrochemical testing in artificial seawater showed that the presence of Cu in Al coatings did not trigger considerable deterioration in corrosion resistance. Further antifouling testing of the coatings by examining settlement and colonization behaviors of bacteria E. coli and Bacillus sp. and typical marine algae revealed their excellent antifouling performances. The antifouling properties were predominately attributed to the continuous release of copper ions from the coatings. The results give clear insight into constructing anti-corrosion/fouling inorganic coatings by the cored-wire arc spray technical route for marine applications.