Impedance of a passive iron electrode in a solution containing a reducing agent

Frequency dependences of impedance of a passive iron electrode in 0.5 M Na2SO4 solutions with and without 0.01 M K-4[Fe(CN)(6)] are obtained by a pulsed method and the Fourier transform. At 1-1000 Hz, the results in 0.5 M Na2SO4 satisfactorily agree with our previous results obtained by a lock-in method. With the [Fe(CN)(6)](4-) ions present, the impedance decreases faster at lower frequencies. The impedance of the oxide film/solution interface relaxes longer the film impedance. These conclusions are similar to those obtained earlier.