Advances in understanding atmospheric corrosion of iron. II. Mechanistic modelling of wet dry cycles

Abstract With the aim of predicting the long term atmospheric corrosion behaviour of iron, the mechanisms occurring inside the rust layer during a wet–dry cycle are considered as well as the characteristics of the rust layer formed during this process. A first step in modelling the behaviour is proposed, based on the description of the cathodic reactions associated with iron oxidation: reduction of a part of the rust layer (lepidocrocite) and reduction of dissolved oxygen on the rust layer. The blocking of the anodic sites is considered to describe the extinction of electrochemical corrosion during the drying. The modelling, by including some composition and morphological data of the rust layer as parameters is able to account for the metal damage after one wet–dry cycle.