Abstract: The equation of transient response for the system with Rs(C₁(R₁(C₂(R₂(C₃R₃))))) equivalent circuit was presented, and some other transient response equations to a small amplitude coulostatic perturbation for multi-time constant electrode processes were also deduced. In the present work, impedance spectra were obtained by transforming coulostatic transient data in time domain into the frequency domain. Using this method, the number of time constant can be determined easily, and the kinetic parameters of the studied electrode process can be estimated correctly. The validity of the proposed method is demonstrated by calculation results based on equivalent circuit and one real corrosion system.

Key words: Coulostatic, Laplace transform, Parameter determination, Time constant