MODELING THE EFFECT OF INHIBITORS ON THE ELECTROCHEMICAL REACTION-KINETICS DURING THE ACID CORROSION OF IRON

A model for the electrochemical corrosion of iron in acid solutions in the presence of inhibitors is presented. It is assumed that the catho dic reaction occurs by a delayed discharge mechanism and that the anod ic reaction occurs by a Bokris mechanism. Inhibition of both the catho dic and anodic reactions in the presence of inhibitors is due to a blo cking effect. The degree to which the surface is covered by the surfac tant molecules depends on the potential and the pH of the electrolyte. Using a computer-controlled experiment, it was shown that changes in the values of the anodic and cathodic Tafel constants b(c) and b(a) an d that changes in the order of the cathodic and anodic processes are n ot associated with changes in the mechanisms of these processes in the presence of inhibitors.