Crystallization and glass transition kinetics in Cu+ ion substituted Cux–Ag1 − xI–Ag2O–V2O5 superionic glasses

Abstract

Crystallization kinetics and thermal properties in superionic glasses CuxAg1 − xI–Ag2O–V2O5 for x = 0.1–0.3 have been thoroughly investigated. X-ray diffraction and differential scanning calorimetry measurements confirm the precipitation of at least three compounds during crystallization, viz. AgI, Ag4V2O7 and Ag8I4V2O7. The activation energies for structural relaxation (Es) and crystallization (Ec) obtained using Moynihan and Kissinger formulation exhibit interesting trends with CuI substitution. The Es value decreases with CuI substitution in the system. Further, the Ec values corresponding to precipitation of Ag4V2O7 and Ag8I4V2O7 exhibit increasing trend, whereas, for that of AgI precipitation a decreasing trend with CuI content. The Avrami parameter calculated from Augis–Bennett method and Ozawa equation suggests predominantly surface crystallization in the glassy system. The electrical conductivity–temperature (σ–T) cycles interestingly demonstrate increasing precipitation of AgI with CuI content in the glass matrix.