Effect of coating composition on the micro-galvanic dissolution behavior and antifouling performance of plasma-sprayed laminated-structured Cu-Ti composite coating

Marine biofouling is a critical issue significantly deteriorating the service performance of marine infrastructures. Thus, development of an effective and long-lasting antifouling coating is highly desirable. Here, a laminated-structured copper-titanium (CuTi) antifouling coating was fabricated by plasma spraying of mechanically blended Cu and Ti powders. The coating was designed to enable controlled release of Cu ions from Cu/Ti micro-galvanic cells and thus to achieve effective and long-term antifouling performance. The effect of Cu-Ti coating composition on its micro-galvanic dissolution behavior and antifouling performance was systematically investigated. The coating compositions were changed by varying Cu content from 8.1 to 65.2%. Analysis of scanning Kelvin probe force microscopy and long-term immersion test results indicated that Cu loading within Cu-Ti coating exhibited little influence on the formation and mechanism of Cu/Ti micro-galvanic cells. However, the Cu ions release rate and antifouling duration increased with increasing Cu loading. The antifouling efficiency of Cu-Ti coating against bacterial survival increased with the increase in the Cu loading from 8.1 to 19.2% and it reached similar to 100% when Cu loading exceeded 19.2%. Electrochemical test results revealed that with the variation of Cu loading, the amount of micro-galvanic cells rather than the dissolution rate of each single micro-cell played a more prominent role in deciding the total Cu dissolution rate; and consequently, the Cu ions release rate and self-polishing rate. These results may guide the advanced design of versatile Cu-Ti antifouling coatings with environment-friendly, durable, and remarkable antifouling capability for different practical requirements in marine engineering through facilely tailoring coating composition.

Automated summary

The Cu-Ti coating with varying copper content showed influence on its micro-galvanic dissolution behavior and antifouling performance, with higher copper content leading to increased copper ions release rate and antifouling duration against bacterial survival. Electrochemical tests revealed that the amount of micro-galvanic cells, rather than the dissolution rate of each single micro-cell, played a more prominent role in deciding the total copper dissolution rate and antifouling capabilities.