New methods were developed for determining self-diffusion coefficients in oxides. These involved the use of Raman spectroscopy, combined with the 16O-18O exchange technique. Here, the method was applied to tetragonal polycrystals of material which contained 2.8mol% of Y2O3. It was found that the results could be described by:

D (cm2/s) = 0.182 exp[-139.3(kJ/mol)/RT]

at temperatures of between 700 and 950C. The diffusivity was also measured by using a gas-monitoring method during the isotopic exchange reaction. The data which was described in this manner could be described by:

D (cm2/s) = 0.0114 exp[-117.5(kJ/mol)/RT]

at temperatures of between 700 and 1165C. Good agreement was found between the data which were obtained by using the 2 methods.

B.K.Kim, S.J.Park, H.Hamaguchi: Journal of the American Ceramic Society, 1994, 77[10], 2648-52