Measurement of I-E Curve of Carbon Steel in Fresh Water

摘要

The electrochemical method to obtain the i-E curve of carbon steel in the fresh water has been developed. The electrochemical impedance spectra were measured during the measurement of potentiodynamic polarization curve. The precise solution resistance could be determined by the 3-D impedance plots, and the iR drop was compensated for the i-E curve. Furthermore, the variation of the solution resistance was monitored to discuss the variation of solution nature during the measurement of i -E curve. The Pd-H electrode was employed as a reference electrode, because the Pd-H electrode is stable in the aqueous solution and yields no contamination of the solution. Beside, the electrochemical cell in which the solution was impinged onto the working electrode was constructed in order to avoid the variation of the solution composition due to the working electrode reaction. The present method was applied to the measurement of i-E curve of carbon steel in the tap water, and the relationship between i-E curve and the corrosion mechanism of the carbon steel was discussed.