Anion self-diffusion normal to (1¯1•2) was measured in single crystals at 1585 to 1840C, in vacuum, by using radiotracer methods. The diffusivity in pre-annealed crystals could be described by:

D (cm2/s) = 6.4 x 105 exp[-188(kcal/mol)/RT]

The diffusion was attributed to an extrinsic vacancy mechanism. Crystals with surface damage exhibited enhanced diffusion.

D.J.Reed, B.J.Wuensch: Journal of the American Ceramic Society, 1980, 63[1-2], 88-92