The self-diffusion of 18O was measured, using secondary ion mass spectroscopy, in monocrystals and polycrystals of Y2O3-doped α-Al2O3 at 1110 to 1630C. Two mechanisms were involved in the case of monocrystals. These were a bulk diffusion mechanism and a sub-boundary one. Both mechanisms were observed at high temperatures while, at lower temperatures, bulk diffusion predominated. The lattice diffusion coefficients could be described by:

D (cm2/s) = 6.7 x 101 exp[-141(kcal/mol)/RT]

It was concluded that Y slightly increased O bulk diffusion.

M.Le Gall, B.Lesage, N.Brun, A.M.Huntz, M.Miloche, C.Monty: Materials Science Forum, 1993, 126-128, 411-4