Development of Corrosion Diagnosis Method of Copper in Fresh Water by Combining Amperometry and Potentiometry

Abstract

A new corrosion diagnosis method was proposed for the diagnosis of copper corrosion in fresh water combining amperometry and potentiometry. The procedure for the corrosion diagnosis was described as follows : The potentiostatic polarization of copper electrode is performed at 0.2 V vs. SSE for 600 s to record the current, i_0.2V, in the fresh water. The current of 500 µA cm^–2 is then applied to the copper electrode for 600 s to measure the potential, E_{500 µA cm–2}, in the fresh water. The three–dimensional diagram, called as the corrosion map 3D, composed of i_0.2V, E_{500 µA cm–2} and pH of the fresh water is developed. In the present study, the different concentrations of test solution were used for the above–mentioned measurement in order to obtain the i_0.2V, E_{500 µA cm–2} and pH of each test solution. The obtained results were applied to the corrosion map 3D, indicating that the corrosion morphology of copper in the various concentrations of test solution could be divided into three corrosion categories (general corrosion, pitting corrosion, no corrosion).