SEDL / STP / STP727-EB / STP28040S

Direct Measurement of the Corrosion Current for Oxygen-Reduction Corrosion

Postlethwaite, J
Professor, University of Saskatchewan, Saskatoon,

Pages: 13    Published: Jan 1981

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Abstract

The polarization-resistance technique has received considerable attention in the past decade as a means of determining the rate of corrosion. In aerated solutions of pH greater than 4, where oxygen reduction is the major cathodic reaction, there is a much simpler and more direct method of determining the corrosion current. The method involves the deaeration of the solution while the corroding specimen is held potentiostatically at its previously determined corrosion potential (E^corr). The current supplied by the potentiostat when the solution is deaerated is the corrosion current (i^corr). This method is suitable for laboratory and pilot-plant scale testing when the solution can be deaerated. The application of the method for the measurement of corrosion rates under controlled hydrodynamic conditions in pilot-plant pipelines carrying water and aqueous slurries is discussed along with the limitations of the method.