Alkaline-Earth Diffusion in Mixed Cation Glasses
Diffusion of alkaline-earth ions in mixed cation glasses of the composition xA2O•(3-x)MO•4SiO2 (x = 0.0, 0.1, 0.3, 0.4 and 1.0; A = Na, K; M = Ca, Ba) was investigated by means of the radiotracer diffusion technique below the respective glass transition temperatures. The mobility of alkaline-earth ions increases with the alkali content in all analyzed glass systems with no decrease in the diffusion activation energy, but a raise in the pre-exponential factor. A distinct dependency of the activation energy of the alkaline-earth ions on the type and content of the alkali ions in the glass is observed. Additional experiments with thin glass films derived by the sol-gel technique reveal an analogous diffusion behaviour. This demonstrates that the dynamic of alkaline-earth ions in mixed cation glasses does not depend on the way of glass preparation.
A. Agüero, J.M. Albella, M.P. Hierro, J. Phillibert and F.J. Pérez Trujillo
M. Grofmeier et al., "Alkaline-Earth Diffusion in Mixed Cation Glasses", Defect and Diffusion Forum, Vols. 289-292, pp. 615-620, 2009