KINETICS OF GROWTH OF ANODIC OXIDE-FILMS ON NIOBIUM

Kinetics of growth of anodic oxide films on niobium in mixed solution of aqueous electrolyte (disodium hydrogen phosphate) with diethylene g lycol at different temperatures and different current density sets hav e been obtained. Various parameters of anodic oxidation have been eval uated using Dewald's theory. The entrance barrier energy has been foun d less than the corresponding diffusion barrier energy and this sugges ts that the rate controlling step in the kinetics of growth of anodic film is the ionic movement across the film and not at the metal/oxide interface.