The formation and growth of thin anodic films on In in slightly alkaline borate bulk solutions was studied by using galvanostatic and cyclic voltammetric techniques. Under galvanostatic conditions, oxide film growth occurred via activation-controlled ionic conduction (with a high electric field across the film) according to the exponential law. The kinetics of film growth were examined with regard to the electric field strength (which was of the order of 106V/cm), the reciprocal capacity, the constants in the exponential law, the height of the energy barrier to ion transport in the oxide, the effective activation distance for ionic jumps over the energy barrier, and the pre-polarization oxide thickness. By using cyclic voltammetry, evidence was presented for the primary passivation of In under dynamic conditions. It was found that the oxide film formation occurred under ohmic resistance control. Changes in the latter resistance were caused by the nucleation and spread of the oxide as a layer on the metal surface.

S.Omanovic, M.Metikoš-Hukovic: Solid State Ionics, 1995, 78[1-2], 69-78