Voltammetric Analysis on the Formation of Fe(OH)2 and FeCO3, and on the Reactivity of Passivation of Steel in Carbonate Solutions

This paper examines the simultaneous dissolution and the formation of Fe(OH)2 and FeCO3 in carbonate solutions. It re-evaluates some of the early findings on Fe(OH)2 outlining that it forms with kinetics interfering with that of FeCO3. The formation and electroreactivity of FeCO3 are investigated in detail. The electrochemical significance of the thickness and reactivity of the passive films are linked to the carbonate concentration, cyclic voltammetry scans, and the cathodic reduction of oxygen and water. The cathodic currents were indicative of the thickness and reactivity of the passive films, which increased with the carbonate concentration and higher cycling.