The self-diffusion of O in undoped alumina monocrystals was investigated by using the gas-solid isotope exchange technique. After diffusion annealing, the profiles of 18O were determined by means of secondary ion mass spectrometry. This revealed 2 parts, in which the behavior close to the initial surface was attributed to bulk self-diffusion while the diffusion tails were attributed to migration in dislocation walls. At 1500 to 1720C, the O diffusivity in sub-boundaries could be described by:

D (cm2/s) = 3.1 x 1014 exp[-213(kcal/mol)/RT]

D.Prot, C.Monty: Philosophical Magazine A, 1996, 73[4], 899-917

The best linear fits to the solute diffusion data ([430] to [437]) yield:

O: Ln[Do] = 0.20E – 24.5 (R2 = 0.99); O(gb): Ln[Do] = 0.37E – 45.4 (R2 = 0.96)