The corrosion protection performance of repair coatings for offshore wind power constructions after long-term splash zone site exposure

Four organic repair coatings are applied to low-carbon steel samples prepared with rotating wire blasting, and the samples are exposed to the splash zone in an offshore environment (Helgoland, North Sea) for 57 months. The relationships between aging procedure, coating type, and corrosion protection performance are systematically investigated with statistical methods. Design of experiments and analysis of variance are used to rank the parameter effects. Response parameters are the degree of coating delamination and pull-off strength. Extremely significant interactions are found between aging procedure and delamination and between coating type and pull-off strength. An extremely significant interaction between the factors aging procedure and coating type is found for the pull-off strength only. The degree of delamination is alternatively discussed in terms of the delaminated area. Acceleration factors, calculated from results of the site exposure tests and of accelerated cyclic laboratory test, range between 5.2 and 8.6.