Development of Novel Coating Systems for Mitigating Corrosion of Offshore Wind Turbines

Offshore wind turbines are subjected to harsh and extremely corrosive environments. Seawater, UV radiation, temperature variations, seaborne debris and floating objects make the atmospheric, the tidal and especially the splash zone the worst of all. Usually, cathodic protection is used for corrosion protection in metallic structures. Due to lack of continuous electrolyte (seawater) layer between the structure and the anode, this method proves to be inefficient in these zones. Hence, another approach for mitigating corrosion is applied, which is studied in this research. This work examines the behaviour of protective epoxy-based paint coating, which rely on its barrier properties. To ensure wind turbines’ long-term protection, this coating is enriched with components, which can protect them from corrosion when damaged. To manage this, commercially available marine epoxy paint is modified to autonomous system via addition of encapsulated corrosion inhibitors/self-healing agents, silanes. The idea is that once the coating is damaged, the capsules will rupture and release the core material and eventually stop the propagation of the scratch. Polymerisation reactions lead to solidification of the liquid core, filling the scratch. During the completion of the polymerisation reaction the substrate metal is exposed to a corrosive environment, thus the use of a sacrificial Zn/Al coating is also investigated. The combination of the enriched paint and of the sacrificial thermal spray coating allows for further development of coating systems. The final aim of this research is to present the “Development of novel coating systems for mitigating corrosion of offshore wind turbines”. This development will have an impact on the reduction of their maintenance and replacement costs. Hence, it will ensure protection against corrosion, extension of their service life and reduction of catastrophic incidents that could have devastating social, environmental and financial consequences.