Kinetics of phase transition and thermal stability in Se_(80-x)Te_(20)Zn_x (x 5 2, 4, 6, 8, and 10) glasses

摘要

Se_(80-x_Te_(20)Znx (x = 2, 4, 6, 8, and 10) glasses have been prepared using conventional melt quenching technique. The kinetics of phase transformations (glass transition and crystallization) have been studied using differential scanning calorimetry (DSC) under non-isothermal condition at five different heating rates in these glasses. The activation energy of glass transition (E_t), activation energy of crystallization (E_c), Avrami exponent (n), dimensionality of growth (m), and frequency factor (K_o) have been investigated for the better understanding of growth mechanism using different theoretical models. Theactivation energy is found to be highly dependent on Zn concentration. The rate of crystallization is found to be lowest for Se_(70)Te_(20)Zn_(10) glassy alloy. The thermal stability of these glasses has been investigated using various stability parameters. The values of these parameters were obtained using characteristic temperatures, such as glass transition temperature T_g, onset crystallization temperature T_c, and peak crystallization temperature T_p. In addition to this, enthalpy-released during crystallization has also been determined. The values of stability parameters show that the thermal stability increases with the increase in Zn concentration in the investigated glassy samples.