Corrosion Protection for Wind Power Plants – The Influence of the Application Conditions by Thermally Spraying on the Corrosion Behaviour of ZnAl Coatings

The aim of this study is to compare the quality of corrosion-resistant thermal spray coatings depending on where and how they are applied. ZnAl₁₅ coatings were applied to S235 steel substrates by wire arc spraying in keeping with standard (EN ISO 2063) practice. The coatings were sprayed under factory conditions and in a simulated onsite environment using manual and automated methods. As-sprayed and sprayed-and-sealed coating samples were subjected to climate-cycle and corrosion testing. Coatings applied onsite varied in quality to a much greater extent than those sprayed under workshop conditions. Poor quality, and implicitly a lower corrosion resistance, was widely detected in coatings where ZnAl was manually sprayed under simulated onsite conditions. The implications of the study are particularly relevant to the sustainability of coastal and offshore wind power generators due to maintenance challenges.