THE INFLUENCE OF OXYGEN-CONTAINING OXIDANTS ON THE RATES OF CATHODIC EVOLUTION AND PENETRATION OF HYDROGEN INTO THE METAL

The oxidants were shown to have a dual effect on the rates of hydrogen evolution and penetration into the metal. Reduction of oxygen and oxo anions gives rise to an increase in solution pH near the electrode and therefore lowers the rate of hydrogen-ion discharge. The values of cr itical oxidant concentration that correspond to a minimal rate of hydr ogen penetration into iron were determined. Dependences of the rates o f hydrogen evolution and penetration into the metal on the oxoacid con centration exhibit peaks with magnitudes that are determined by the el ectrode potential, solution pH, and the degree of metal surface hydrop hily. The interrelations between the reactions of oxidant reduction an d hydrogen-ion discharge were explained in terms of spatial separation of the reactants in the compact part of the electrical double layer.