Advances in corrosion protection by organic coatings: What we know and what we would like to know

It is shown how heterogeneity leading to electrochemical variations is important both in polymer structure (i.e. local variation in polymer conductivity influenced by the external electrolyte) and in light alloys (e.g. 2nd phase particles act as local cathodes or anodes). The conclusion is that no single protective mechanism is operative in organic coatings. Long-term performance is predicated on a number of complementary processes working holistically. By developing an understanding of the mechanisms and critical factors behind long-term performance, a predictive toolkit for “how paint fails” might usefully be created.