Caloric Study of the Bulk Chalcogenide (Bi1Te15Se84-xPbx) Quaternary Alloy System

Bulk glasses of the composition Bi1Te15Se84-xPbx, where 0 ≤ x ≤ 8, were synthesized by conventional melt-quenching methods. The crystallization and thermal kinetics of these alloys were investigated through differential thermal analysis (DTA) at various heating rates of 5 K/min, 10K/min, 15 K/min, and 20 K/min. Key kinetic parameters, including the activation energies, were derived from models like Kissinger’s and Augis-Bennett’s using the functional relationship between heating rate and glass transition temperature (Tg). Interaction of glass transition and crystallization activation energies were tracked as a function of different heating rates and compositions. The amorphous-to-crystalline phase transition, glass-transition behavior, and glass-forming ability of the chalcogenide alloys are described in detail. Important thermal parameters: activation energy for crystallization and glass transition, fragility index, and Hruby’s parameter were calculated. The empirical methods were used to estimate Ec and Eg. The average activation energy for crystallization is (122.93±2.95) kJ/mol, whereas for glass transition, it is (203.45±4.12) kJ/mol. The reduced glass transition temperature (Trg) together with the fragility index (Fi) confirmed that the glassy alloy derived from a good glass-forming liquid. The focus of this manuscript is the preparation of glass using the conventional melt-quenching technique and the study of their structural and thermal properties, which is the fundamental basis for this research work.