The O self-diffusion coefficient for samples which contained between 12 and 16mol%MgO was determined by using the isotope exchange technique and an 18O tracer. The results for single-phase cubic material containing 12mol%MgO could be described by:

D (cm2/s) = 1.02 x 10-4 exp[-15(kcal/mol)/RT]

With decreasing temperature, the O self-diffusivity tended to deviate to lower values with increasing apparent activation energy. The temperature dependence of the diffusion coefficients below 1400C indicated that the activation energy here was equal to about 150kJ/mol.

K.Ando, Y.Oishi, H.Koizumi, Y.Sakka: Journal of Materials Science Letters, 1985, 4[2], 176-80