THE EFFECT OF THE ANOMALOUS DISSOLUTION OF METALS - KINETICS OF IRON DISSOLUTION IN SULFURIC-ACID ELECTROLYTES UNDER CATHODIC POLARIZATION

The time dependences of the dissolution rate of iron cathodes with var iously treated surfaces are studied. The surface layer of a mechanical ly polished metal is shown to dissolve at an anomalously high rate, wh ich explains the potential independence of the mass losses measured fo r the same, relatively short time period. After removing the surface l ayer, the dissolution rate of iron depends on the potential close to t he Tafel equation with a slope of similar to 50 mV, and below -0.45 V, the dissolution practically stops. The surface-defective layer of iro n dissolves electrochemically, hydroxyls being involved in the process . The effect of hydrogen sorbed by iron on the dissolution rate is als o studied.