THE COMPARATIVE ROLES OF OXYGEN AND INHIBITORS IN THE PASSIVATION OF IRON. II. THE PERTECHNETATE ION

Galvanostatic and potentiostatic polarizations of passive iron electrodes have been made in solutions of a phthalate or pertechnetate and mixtures of them. By measuring the polarizations both in oxygen and in essentially oxygen-free helium the relative contributions of oxygen and the reducible inhibitor to the total cathodic current have been determined. An acceleration of the cathodic processes by the reduction product of the pertechnetate ion was demonstrated. It was shown also that, in all cases, reduction of oxygen is the principal cathodic process at passive potentials.