It was demonstrated that (H+, e-) ambipolar diffusion in the γ-phase gave rise to an appreciable internal (Nernst) field. It was found that proton diffusion was accelerated, while electrons were slowed down, by this field. However, they diffused into the dioxide with a common velocity. The γ-phase chemical formula of Ruetschi's model was used. The initial concentration of (H+, e-) played an important role. The effective ambipolar diffusion coefficient was twice that for proton diffusion, and the latter was of the order of 10-9cm2/s. By using the present diffusion model, it was possible to interpret various aspects of the chemical and electrochemical reactivity of the γ-phase. On the other hand, the β-phase - with its zero initial proton concentration - did not give rise to such a beneficial internal field.

H.Kahil: Journal of Physics - Condensed Matter, 1995, 7[17], 3227-35