Kinetics of Tantalum Corrosion in Aqueous Electrolytes, II

Abstract

Transients of the voltage between a tantalum foil and an aqueous electrolyte have been induced by application of d‐c current or else a ‐c voltage steps during the growth of a thin protective oxide film. These transients were analyzed in terms of the dependences on voltage and oxide thickness of (a) the ionic current causing the oxide growth and (b) the current required for charge neutralization. Certain discrepancies between the theoretical model used to analyze the transients and the experimental data indicate a more complex behavior of the oxide than that of an ideal capacitor shunted by a voltage dependent resistor responding instantaneously to changes in the voltage.