Lifetime Prediction of Organic Coatings on Steel

Abstract

ABSTRACTA review of methods for predicting the lifetime of protective organic coatings on steel is presented in terms of a model which includes the steps of defect formation, transport of corrodents, loss of adhesion, and corrosion. Electrochemical impedance methods and acoustic techniques have played important roles in characterizing how the four processes interact and depend on coating processes and environmental effects. A major result of this work has been the observation that both the anodic and cathodic partial processes of the corrosion reaction limit adhesion of organic coatings on steel by generating tensile stresses and polymer degradation, thereby limiting the life of the protective system.