Crystallization and glass transition kinetics in Cu + ion substituted Cu x–Ag 1 − xI–Ag 2O–V 2O 5 superionic glasses

Abstract

Crystallization kinetics and thermal properties in superionic glasses Cu x Ag 1 − x I–Ag 2O–V 2O 5 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, Ag 4V 2O 7 and Ag 8I 4V 2O 7. The activation energies for structural relaxation (E s) and crystallization (E c) obtained using Moynihan and Kissinger formulation exhibit interesting trends with CuI substitution. The E s value decreases with CuI substitution in the system. Further, the E c values corresponding to precipitation of Ag 4V 2O 7 and Ag 8I 4V 2O 7 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.