2004 Volume 53 Issue 6 Pages 317-321
Unlike the liner polarization technique or the electrochemical impedance spectroscopy (EIS), the electrochemical noise method (ENM) enables to measure the polarization resistance (Rp) of an electrode under the conditions that are free from electrochemical perturbations caused by the application of current. However, as well as by the liner polarization, the measured Rp by the ENM affected by solution resistance (Rs) between the electrodes. Though this might produce a substantial error in the Rp measured in lower conductivity solutions, the effect of Rs on the Rp has been scarcely investigated. In this study, the Rp of a carbon steel electrode in dilute HCl solutions were measured by both the ENM and the EIS, under the same conditions. The error of the Rp by the ENM was evaluated by comparing the Rp by the EIS; the latter is regarded as free from the effect of Rs. The Rp by the ENM was higher than that by the EIS, and their differences were decreased with the concentration of the solution. However the degree of the differences was smaller than the Rs measured by the EIS. This advantage would be brought by the specific electrode configuration used for the experiments.