Durable self-polishing antifouling Cu-Ti coating by a micron-scale Cu/Ti laminated microstructure design

Abstract Marine biofouling is a major issue deteriorating the service performance and lifespan of marine infrastructures. The development of a durable, long-term, and environment-friendly antifouling coating is therefore of significant importance but still a critical challenge in maritime engineering. Herein, we developed a Cu-Ti composite antifouling coating with micron-sized alternating laminated-structure of Cu/Ti by plasma spraying of mechanically mixed Cu/Ti powders. The coating was designed to enable controlled release of Cu ions through galvanic dissolution of Cu laminates from the Cu/Ti micro-galvanic cell in aqueous solution. Results showed that remarkable antifouling efficiency against bacterial survival and adhesion up to ∼100 % was achieved for the Cu-Ti coating. Cu/Ti micro-galvanic cell was in-situ formed within Cu-Ti coating and responsible for its Cu ions release. The successive dissolution of Cu laminates resulted in the formation of micro-channels under Ti laminates near surface, which contributed to controlled slow Cu ions release and self-polishing effect. Thus, environment-friendly antifouling capability and ∼200 % longer antifouling lifetime than that of the conventional organic antifouling coatings can be achieved for the Cu-Ti coating. On the other hand, as compared to the conventional organic antifouling coatings, the Cu-Ti composite coating presented much higher mechanical durability due to its strong adhesion strength, excellent mechanical properties, and two orders lower wear rate. The present laminated Cu-Ti coating exhibits combination of outstanding antifouling performance and high mechanical durability, which makes this coating very potentially candidates in marine antifouling application.