Electrodissolution Kinetics of Iron in Chloride Solutions: IV . Alkaline Solutions Containing Benzotriazole

Abstract

The anodic dissolution of iron in alkaline chloride solutions in the presence and absence of benzotriazole has been investigated by potentiostatic, galvano‐static, and potential sweep polarization. The steady‐state and transient polarization experiments indicate that iron dissolution occurs in the absence (active region) and presence (prepassive region) of a porous prepassive surface film. Anodic Tafel slopes of 60 mV/decade were obtained below (active region) and above (prepassive region) the formation potential of the prepassive film on both uninhibited and inhibited iron indicating the same mechanism of iron dissolution. The results suggest that the prepassive film merely decreases the effective surface area for iron dissolution. The effect of benzotriazole is to decrease further the effective surface area.