The Ag from AgNO3 melts was exchanged, for the Na+ ions in commercial glass slabs, at temperatures ranging from 250 to 375C. Samples which had been ion-exchanged at 300C for 1h were treated isothermally for 1 to 5h, at temperatures ranging from 350 to 600C. The resultant concentration profiles were measured by using electron microprobe techniques, and were used to calculate Ag interdiffusion coefficients via the Matano-Boltzmann equation. The results indicated that the Ag interdiffusion coefficient was concentration-independent when up to 28% of the total number of Na ions in the glass had been exchanged for Ag ions. At higher concentrations, the coefficient became concentration-dependent. The dependences of the interdiffusion coefficient and activation energy upon temperature suggested that, at temperatures of up to 470C, these values corresponded to the diffusion of Ag ions whereas the higher-temperature values corresponded to the diffusion of both Ag ions and atoms; which coexisted simultaneously at 470C.

A.A.Ahmed, E.W.Abdallah: Physics and Chemistry of Glasses, 1997, 38[1], 42-50