Mechanisms of degradation of organic coatings

An overview of protection mechanisms of organic coatings for metallic constructions and products is given. The barrier effect of coatings and protection in local defects are discussed. Basic degradation mechanisms of organic coatings such as anodic and cathodic delamination in vicinity of defects, osmotic and cathodic blistering, mechanical stress assisted blistering, loss of adhesion and chalking are described. Appropriate laboratory tests are proposed for each degradation mode.