Silver ionic conductivity of mixed cationic glasses

New families of glasses in the systems PbI2-Ag2O-TeO2, PbI2-Ag2O-P2O5 and AgI-Ag2O-TeO2 have been prepared and investigated. The glass forming region corresponding to each system has been identified. The amorphous domain of AgI-containing glasses was found to be more extended than that of glasses containing PbI2. Conductivity measurements revealed that the room temperature conductivity of PbI2-Ag2O-TeO2 glasses is close to that of PbI2 -Ag2O-P2O5, while that of glasses AgI-Ag2O-TeO2 is much lower. The conductivity of silver tellurite and silver phosphate glasses increases very rapidly when even a small amount of PbI2 is added to the host glass network. But this initial large increase in conductivity is not observed when AgI is added to the silver tellurite network. The similarity observed between values of conductivity in both phosphate and tellurite glasses containing lead iodide is attributed to the similarity in the characteristics of interstitial spaces, which form due to introduction of PbI2. This attribution is further confirmed by the observations based on the results of the activation energy for conduction, glass transition temperature and molar volume of the glasses. (C) 2000 Elsevier Science B.V. All rights reserved.