Abstract: 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 ba or bc and corrosion current density ic. 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, and the comparison of results obtained by solution analysis and electrochemical measurements shows that the method provides a faithful representation of corrosion behavior. The integral method has 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.

Key words: Coulostatic, Tafel slopes, Integral method, Carbon steel, Sulfuric acid solution