The diffusion of 48V in disordered crystals was measured by using a serial-sectioning technique, at 1100 to 1500C, for x = 0.78 to 1.28. The temperature dependence of the cation tracer diffusivity at each fixed composition was characterized by an Arrhenius behavior at 1100 to 1500C. The Arrhenius parameters decreased rather sharply near to the stoichiometric composition, as the composition increased from the metal-rich to the metal-deficient regime. The activation energy for diffusion decreased from about 71kcal/mol to about 48kcal/mol, and the frequency-factor decreases by nearly 2 orders of magnitude: from about 5cm2/s to about 0.05cm2/s. It was concluded that the significant difference in the cation self-diffusion behaviors between the metal-rich and metal-poor VOx could be attributed to the significant differences in the defect structures within the two regimes. It was concluded that the experimental results for the entire composition range were consistent with diffusion occurring via the migration of monovacancies in equilibrium with defect clusters; the nature of the clusters being different for x < 1 and x > 1.

Cation Self-Diffusion in Disordered VOx. S.Kumarakrishnan, N.L.Peterson, T.O.Mason: Journal of Physics and Chemistry of Solids, 1985, 46[9], 1007-14