COMPUTER-ASSISTED DC AND AC TECHNIQUES IN ELECTROCHEMICAL INVESTIGATIONS OF THE ACTIVE PASSIVE TRANSITION

The interrupter technique presented, using a computer assisted data acquisition and calculation method, allows the determination of the ohmic potential drop (IR-drop) in potentiostatic experiments. The results obtained for the passivation of a 304 stainless steel in low conductivity ethanol/water solutions containing hydrogen chloride show the importance of the accurate correction of the IR-drop to calculate the correct kinetic parameters. Impedance measurements give the same values for the ohmic resistance as the computer-assisted interrupter technique described in this paper. The complex plane plots of the impedance show three capacitive loops before the current density reaches its maximum