Diffusion of Oxygen in Near-Stoichiometric α-Nb2O5

Abstract

Oxygen diffusion coefficients have been determined for near‐stoichiometric α‐Nb₂O₅ over the temperature range of 850° to 1200°C and the oxygen pressure range of 10⁻² to 1 atm. At a constant temperature, the diffusion coefficient is found to be proportional to pO₂^−1/4. Temperature dependence of the diffusion coefficient at a constant oxygen pressure is expressed (in square centimeters per second) by D=1.72×10⁻²× exp[— (49.4±3.3 kcal) / RT]. Results are discussed in terms of an oxygen‐vacancy model of nonstoichiometric disorder.