Self-diffusion was measured in cubic monocrystals which were doped with 9.5mol%Y2O3. The O diffusion coefficients were deduced from profiles which were obtained by gas/solid 18O/16O isotopic exchange. Two volume diffusion mechanisms were detected. One of these was a fast O diffusion process which was noted here for the first time. It could be described by:

D (cm2/s) = 6.54 x 10-1 exp[-28.3(kcal/mol)/RT]

at 310 to 1100C. There was also a slow O diffusion process for which the coefficients were similar to those previously published. The slow process could be described by:

D (cm2/s) = 3.77 x 10-4 exp[-18.6(kcal/mol)/RT]

at 500 to 1100C. The majority defects were O vacancies which compensated the charge deficiency that was introduced by Y. Connected micro-domains which contained complex defects appeared to be responsible for the faster diffusion. The slower diffusion was explained in terms of free O vacancy migration in the disordered crystal.

H.Solmon, C.Monty, M.Filal, G.Petot-Ervas, C.Petot: Solid State Phenomena, 1995, 41, 103-12

The best linear fit to the solute diffusion data ([468] to [470]) yields:

O: Ln[Do] = 0.27E – 11.7 (R2 = 0.27)