Ionic Diffusion Oxidation Model of Uranium

A theory-driven model is formulated for the low-temperature oxidation of uranium exposed to oxygen. The model is based on diffusion of oxygen ions through the oxide film driven by the electrostatic potential generated between the metal and adsorbed oxygen ions. The model fits published experimental data well for temperatures between 20 degrees C and 200 degrees C and for oxide film thicknesses less than 300nm. The derived reaction rate coefficients for parabolic and inverse logarithmic growth regimes correspond well to the available published values and outperform the existing empirically derived forms. These reaction rate coefficients can be applied to the oxidation of any metal that is driven by the generated electrostatic potential.