Thermal stability and activation energy of some compositions of Ge–Te–Cu chalcogenide system

Abstract

The present study investigates the influence of copper addition on the thermal stability, and the activation energy of the glass transition and crystallization for Ge₂₆Te_{74− x} Cu _x (x = 2.5, 5, 7.5, 10 and 12.5 at%) glasses. Differential scanning calorimetric (DSC) results under non-isothermal conditions for the Ge–Te–Cu system are reported and discussed. From the heating rate (α) dependence of the glass transition temperature (T _g) and the temperature corresponding to the maximum crystallization rate (T _p), the activation energy for both glass transition and crystallization for the studied glasses were obtained. The glass-forming ability of the Ge₂₆Te_{74− x} Cu _x glasses was evaluated using various thermal stability criteria based on characteristic temperatures. The K _r(T) criterion has also been considered for the evaluation of glass stability from DSC data. The activation energy for crystallization decreases and thermal stability increases with increasing copper content.

Keywords:

• thermal stability
• activation energy
• differential scanning calorimetry

Acknowledgement

The authors thank Al-Azhar University for financial support.