Self-diffusion of oxygen in single crystal alumina

Abstract

The self-diffusion coefficient of oxygen in (polished slices of a Verneuil) single-crystal alumina was determined in the temperature range 1500–1770 °C by means of the gas–solid isotope exchange technique. The results were represented by D=1.12×103 exp (−155×103/RT) cm2/s. The activation energy was interpreted to be for intrinsic diffusion. By comparison of the results with the oxygen self-diffusion coefficients previously reported for crushed particles of a Verneuil alumina and a vapor-grown alumina, the extrinsic diffusion exhibited by the crushed particles was confirmed to be due to a dislocation enhancement process.