A thermodynamic and kinetic investigation of amorphous (1−x)As2Se3 · xSb2Se3 alloys

TLDR: In this article, the authors measured changes in microhardness, small-angle X-ray scattering and heat capacity with time of annealing at several temperatures ranging from room temperature to 413 K.

Abstract: The heats of formation of amorphous (1− x )As 2 Se 3 · x Sb 2 Se 3 ( x = 0 to 0.4) referred to crystalline As 2 Se 3 and Sb 2 Se 3 were measured by liquid metal solution calorimetry. The values of heats of formation of amorphous (1− x )As 2 Se 3 · x Sb 2 Se 3 decreased from 1.39 ± 0.03 kcal · (g-at) −1 at x = 0 to 1.27 ± 0.04 kcal · (g-at) −1 at x = 0.4. The glass transition temperature and the temperatures of the maximum rates of crystallization and fusion were measured by differential scanning calorimetry. The glass transition temperature increased and the temperatures of the maximum rates of crystallization and fusion decreased with increasing Sb 2 Se 3 content. The relaxation process in amorphous (1− x )As 2 Se 3 · x Sb 2 Se ( x = 0.3) was investigated by measuring changes in microhardness, small-angle X-ray scattering and heat capacity with time of annealing at several temperatures ranging from room temperature to 413 K. With increasing annealing time the microhardness, the height and the temperature of the glass transition peak increased whereas the intensity of small-angle X-ray scattering decreased. These changes reflect relaxation towards a more stable structure of smaller molecular mobility. The changes in the enthalpy with annealing time and the activation energy spectra for relaxation were derived from the heat capacity data. The effects of temperature and time of annealing on the various properties are explained in terms of structural changes and relaxation kinetics.