Calorimetric analysis of non-crystalline TeO2–V2O5–Sb2O3

Abstract

In the present report, thermal and physical characterization of 40TeO2–(60 − x)V2O5–xSb2O3 glasses, prepared by melt quenching method, has been investigated by differential scanning calorimetry (DSC) and so discussed in the compositional range 0 ≤ x ≤ 10 mol%. DSC plots of these ternary glasses have been studied within the temperature range of 150–500 °C at the heating rates φ = 3, 6, 9, 10 and 13 K min−1. In this work, thermal stability, glass-forming tendency, the temperature corresponding to the onset of crystallization (Tx), the crystallization temperature (TCr), the glass transition temperature (Tg), the activation energy of crystallization by using Ozawa and Kissinger methods, and the crystallization activation energy using Avrami index (n) have been measured and reported, to determine the relationship between Sb2O3 content and the thermal stability in order to interpret the structure of glass. In conclusion, from the obtained data, it was found that characteristic temperatures Tg, Tx and Tcr are increasing with increasing the antimony oxide content and also with increasing the heating rate; glass with x = 10 has the highest thermal stability and glass-forming tendency and so has very good resistance against thermal attacks; the sample S5 shows a sharp decrease in the crystallization activation energy, which can be resulted by the increase in non-bridging oxygens; the crystallization activation energy calculated from Kissinger’s model is more accurate, and the trend of activation energy values is similar in all of Ozawa, Kissinger and Avrami methods; also the obtained values of n show that it fluctuates around n ≈ 1, which can be attributed to surface or one-dimensional crystal growth of crystals.