Oxygen tracer diffusion was studied in rutile at 1273K, and in Magnéli phases, TinO2n-1 (n = 3 to 8) at 1413K. Mass spectrometry was used to analyse a gas atmosphere enriched in 18O. Pure oxygen atmospheres were used to study rutile, while studies of the Magnéli oxides involved hydrogen/water buffers to set up suitable oxygen gas potentials. For a rutile particle size of 75 to 150µ, under an O pressure of 1.98kPa at 1273K, the diffusivity was 2.15 x 10-16m2/s. For a particle size of 150 to 300µ, under an O pressure of 2.14kPa at 1269K, the diffusivity was 6.79 x 10-17m2/s. Anion diffusion was slower in the lower oxides (table 6) than in rutile.

Oxygen Tracer Diffusion in the Magnéli Phases TinO2n-1. Bagshaw, A.N., Hyde, B.G.: Journal of Physics and Chemistry of Solids, 1976, 37[9], 835-8

Table 6

Tracer diffusion of O in TinO2n-1 at 1413K