Effects of impact damages on the performance of offshore wind power coatings after accelerated ageing

Damages to multilayer organic coating systems due to impact loads can deteriorate the corrosion protection performance of the coatings under offshore exposure. The contribution is concerned with statistical investigations into the effects of load-based and coating-based factors on the protection performance of impinged coating systems for offshore wind power structures. Accelerated cyclic laboratory tests were performed on damaged multilayer coating systems, and the results were statistically analysed. Results of analysis of variance revealed that the effects on the integral corrosion protection performance of the coatings (anticorrosive effect, AE) were dominated by the factor ‘load intensity’ (impact energy). This factor could explain 34% of all effects. It also was the only significant factor. The load-based factor ‘damage area’ affected the coating delamination and was extremely significant, but it did not affect the AE. Coating-based factors, namely ‘coating system’, ‘total dry film thickness’ and ‘pull-off strength’, did not deliver effects to AE and were statistically insignificant. The factor ‘coating system’ was statistically insignificant for delamination and for AE. ‘Unknown’ effects, not considered in this study, delivered the highest contributions to the regression models (50% to 68%), indicating that additional parameters/factors of the coating systems must be considered when developing impact-resistant coatings.