Corrosion performance of thermal sprayed aluminum coating in offshore mooring chains

With 39% of mooring chain failures related to different corrosion mechanisms of Floating Production Units [6]. finding a solution to delay or avoid this degradation phenomenon has become one of the offshore industry main concerns. Thermal Sprayed Aluminum (TSA), aluminum based coating, has been used as corrosion protection in chains since 2001. However, its behavior and durability in different conditions remains a question. In the present work, corrosion behavior of the TSA is analyzed and compared to base steel material, simulating real seawater conditions, including atmospheric, splash and immersed zones. In order to evaluate TSA performance, the coating effectiveness was measured under different ageing processes and mechanical actions. Additionally, the capability of the coating to tolerate damages and its response under different cathodic potential levels were assessed. The analyses were conducted combining electrochemical techniques. One-year tests were performed on components both in laboratory, under controlled conditions, and in real environment, using 3D scanning methods to calculate corrosion rates afterward the exposition. Components results were aligned with the previously obtained results on samples. Results showed the benefits of applying TSA to offshore mooring chains by significantly enhancing corrosion resistance.