Three sets of polymer coated steel were exposed to Pacific ocean water (NS) and artificial (AS) sea water. Each set had a different primer - metallic zinc, IVD-Al or phosphate. Within each set one group of samples had an epoxy coating, the other set had an additional layer of polyurethane as a topcoat. Degradation of the protective properties of the polymer coating was followed by recording impedance spectra and electrochemical potential and current noise data as well as by visual observation. Statistical analyses concerning the effects of the nature of the primer, presence of a topcoat and exposure medium (biotic vs. abiotic) were performed based on the breakpoint frequency ...
Keywords: polymer coatings, natural seawater, microbial corrosion, EIS, ENA, laboratory tests, surface analysis.