Abstract: A transient analysis method, based on the coulostatic impulse technique, is developed. This method can compute the polarization resistance and Tafel slopes by analyzing the coulostatically-induced transients with different amplitude over-potential decay and, on the ground of their knowledge, evaluate the corrosion current, icorr. The experimental application concerns the behavior of carbon steel in natural seawater. Experimental results for carbon steel exposed to natural seawater show good agreement between the proposed method and the steady-state polarization curves method with concentration polarization consideration. Additionally, the cathodic Tafel slopes obtained by the coulostatic strong polarization integral (CSPI) method are closer to the theoretical values associated with the oxygen reduction reaction. Therefore, the coulostatic method is very useful in evaluation of the electrochemical corrosion parameters in mixture controlled systems, which enable us to minimize the effect of concentration polarization.

Key words: Coulostatic, Tafel slopes, Mixture control, Carbon steel, Corrosion