05345 RAPID DETERMINATION OF TAFEL （05345年塔费尔的快速测定）.pdf

RAPID DETERMINATION OF TAFEL SLOPES BY AN INTEGRAL METHOD OF COULOSTATICALLY INDUCED TRANSIENTS ZHAO Yong-tao and CHEN Guang-zhang State Key Lab. for Marine Corrosion and Protection Qingdao 266071 P.R.C GUO Xing-peng and DONG Ze-hua Dep. of Chem. Huazhong University of Science and Technology Wuhan, 430074 P.R.C ABSTRACT A new numerical method, based on an integral formulation, for analyzing the coulostatically-induced transients is developed. This method can compute the Tafel slopes b and b and, on the grounds of their knowledge, evaluate the a c corrosion current, Ic. The examination of some numerical examples has shown the effectiveness and reliability of this new approach. The experimental application concerns the behavior of Q235 steel in natural seawater. Comparing the analysis of coulostatically-induced transient curves, CSPI (coulostatic strong polarization integral) method with the conventional method showed that the CSPI method requires a less rigorous restriction on the sampling of response potential, and therefore, it is considered an improved method. A good agreement was found between anodic and cathodic Tafel slopes obtained by traditional Tafel analysis and those obtained by new CSPI method. Furthermore, the cathodic Tafel slopes obtained by the CSPI method are closer to the theoretical values associated with the oxygen reduction reaction. Consequently, it is feasi