Non-isothermal crystallization of TeO2-Na2O-TiO2 glasses

Publication date: 15 November 2019Source: Journal of Non-Crystalline Solids, Volume 524Author(s): J.V. Gunha, A. Somer, A. Gonçalves, S. do R.F. Sabino, R. El-Mallawany, C. Jacinto, A. NovatskiAbstractGlass samples in the form 80TeO2-(20-x)Na2O-xTiO2 with x = 0, 5, 10, 15 and 20 mol%, were fabricated by the melting quenching technique. The thermal behavior of samples was analyzed considering their crystallization kinetics mechanism and microstructural analysis. Differential Scanning Calorimetry (DSC) was performed at 20 ml/min argon flux and heating rates of 10, 13, 15 and 20 K/min, from ambient temperature to 873 K, and these data were analyzed using a non-isothermal model of phase transformation. The activation energy for crystallization and Avrami exponent were determined for each sample. We observed that the crystallization process depends on the role assumed by the TiO2, a modifier (5 mol%) or former network (10 and 15 mol%). The crystallization process changes from superficial to internal or three-dimensional crystallizations with increasing TiO2 content.

Source: Journal of Non Crystalline Solids - September 5, 2019 Category: Chemistry Source Type: research