The influence of ionic composition on the electrodissolution and passivation of iron electrodes in potassium carbonate-bicarbonate solutions in the 8.4–10.5 pH range at 25°C

Abstract

The influence of ionic composition on the electrodissolution and passivation of iron electrodes in potassium carbonate/bicarbonate buffers is studied over the concentration range of anions compatible with the regulating capacity of the buffer, at 25°C, by using voltammetric and rotating disc electrode techniques. Data are discussed on the basis that the interaction between Fe²⁺ and HCO₃⁻ ions plays an important role at the outer part of the passivating layer where the local pH resulting from the thickening of the passivating layer is determined by the coupling of different ionic equilibria.