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2009
Journal Article
Title
Investigating corrosion protection of offshore wind towers: Pt.2: Results of the site tests
Abstract
Fouling did not seem to affect the corrosion protection performance of the coating systems. From the point of view of effects on the habitat in the vicinity of the towers, fouling in the UZ and the IZ may become an issue in running offshore wind energy towers in the North Sea. The results of the long-term site tests gave the following ranking of the protection capability of the coating systems: 3, 4, 2, 1. Thus, Zn/Al metallization, followed by two intermediate layers of EP-based paint, is a good choice. The assessment is based mainly on the results obtained from the artificially damaged IZ samples. In the SZ, the flange connection was a critical structural part in terms of corrosion. Notable crevice corrosion was observed at places. Therefore, a suitable sealant between abutting faces may be considered for additional protection against corrosion. The corrosion zones showed no effect on the performance of the coating systems. In contrast to plain steel, which showed accelerated corrosion in the SZ of offshore structures,14,15 the coatings performed equally well, as long as the undamaged areas of the samples were considered. Mechanical damage to the coating initiates paint delamination and corrosion. A recommended coating system, therefore, should be either very resistant to impact or able to compensate for corrosion of the steel. Cathodic protection of uncoated sections in the UZ is an interesting alternative to passive coating systems.