Metallic Coatings for Mitigating Marine Corrosion

Thermally sprayed aluminium (TSA) coatings are increasingly used to mitigate corrosion of offshore pipelines and structures. With the increase in the use, the knowledge related to their performance is growing. However, it would appear that the increased engineering applications is not supported by extensive research and in many cases due to improper application or lack of quality control, some issues are beginning to emerge. The data available in literature on the low and high temperature performance of these coatings is limited. To address the issues highlighted above, TWI carried out several research projects, including JIPs, collaborative projects and PhD projects, to quantify the effect of coatings damage in simulated service conditions at various temperatures. The research thus far indicate that TSA is capable of protecting steel at various temperatures in seawater even when a small through-thickness defect in the coating is present. The presentation will disseminate the results of various projects carried out at TWI and summarize the requirements that needs to be considered while selecting these coatings for offshore service.