The kinetics of iron dissolution and passivation depending on temperature and ionic strength

The anodic behaviour of pure, recrystallized iron in weak acid sulphate solutions in the potential range between the active and the passive state of the metal was investigated. The influences of the temperature and the ionic strength on the kinetic data were studied. The results establish the iron dissolution and passivation mechanism previously proposed from measurements in sulphate and perchlorate solutions of high ionic strength and at room temperature. This mechanism is characterized by the formation of different intermediates [Fe(OH)_n]_ads with n = 1, 2, 3 depending on the potential.