Determination of Tafel Slopes by an Integral Method

摘要

The mathematical model of a three parameter method, based on an integral formulation, for analyzing the coulostatically induced transients is developed. This method can compute the Tafel slopes b_a or b_c and corrosion current density i_c. Experimental data for the system carbon steel/ 0.5M H_2SO_4 are analyzed by the proposed method. The results obtained are very satisfactory. Firstly, the validity of the method is confirmed by the observation that the values of Tafel slope measured by coulostatic method are coincident with those obtained by Tafel lines extrapolation method with eliminating influence of IR drop. Secondly, comparison of results obtained by solution analysis and electrochemical measurements shows that the method provides a faithful representation of corrosion behavior. The integral method have the advantages over differential method due to its simplicity and higher signal/noise ratio, so that the numerical algorithm gives the possibility of higher precision of corrosion measurements