The Effect of Alternating Current on the Rate of Dissolution of Carbon Steel in a Chloride Electrolyte. Part II. Cathode Potentials

Abstract

Under the action of alternating current, the steel dissolution rate increases significantly in a 3.5% NaCl solution at the potentials of cathodic protection of structures. A characteristic “potential–current” dependence corresponding to metal passivation at cathode potentials is obtained. The conditions for forming local corrosion defects under the action of alternating current are determined. It is shown that the dependence of the cathode current on the peak value of the potential differs significantly from those predicted based on the effect of Faraday rectification of the alternating current. The main difference is the appearance of a maximum or an inflection on the “current–peak potential” curves, which can be explained by metal passivation.