The lattice and grain-boundary diffusion coefficients of Yb, which substituted for Y, were determined in high-purity stoichiometric polycrystalline yttrium aluminum garnet at 1400 to 1550C, in air. Ytterbium oxide thin films were produced on the YAG surfaces by using a dipping method. After diffusion, the penetration profiles were established by means of secondary ion mass spectroscopy and the diffusion coefficients were deduced from the thin-film solution of Fick’s equation. The difference between the volume and grain-boundary diffusion coefficients was about 5 orders of magnitude within the above temperature range. The cation activation energies (about 550kJ/mol) were much higher than those for O (300 to 350kJ/mol).

Ytterbium Cation Diffusion in Yttrium Aluminum Garnet - Implications for Creep Mechanisms. M.Jiménez-Melendo, H.Haneda, H.Nozawa: Journal of the American Ceramic Society, 2001, 84[10], 2356-60