| Full text | |
| Author(s): |
Fernandes, Roger Gomes
[1]
;
Valle, Paula Squinca
[1]
;
Franco, Douglas Faza
[1]
;
Nalin, Marcelo
[1]
Total Authors: 4
|
| Affiliation: | [1] Sao Paulo State Univ UNESP, Inst Chem, Araraquara - Brazil
Total Affiliations: 1
|
| Document type: | Journal article |
| Source: | Thermochimica Acta; v. 673, p. 40-52, MAR 2019. |
| Web of Science Citations: | 1 |
| Abstract | |
A series of germanium glasses in the systems (100-x){[}40GeO(2)-30Bi(2)O(3)-20PbO-10TiO(2)]-(x) AgCl with x = 0, 1, 3 and 5 (mol%) was prepared using the melt-quenching method and then characterized taking into account their crystallization kinetics mechanisms and microstructural analysis. Through Differential Scanning Calorimetry (DSC) performed in different linear heating rate programs, the experimental data obtained were based on non-isothermal models of phase transformation, since their versatility allows us to calculate kinetic parameters, for example, activation energy for crystallization (E-c) and Avrami index (n). Thus, it is possible to obtain information on the crystallization mechanism of these glasses. Independent of the model, the values of the Avrami index for each composition are the same, considering the uncertainty attributed to them. It is safe to affirm that bulk and surface nucleation contribute to the crystallization of compositions containing 0 and 1 mol% of AgCl, whereas internal and surface crystallization with one-dimensional growth occur in samples with 3 and 5 mol% of AgCl, respectively. These results were supported by a microstructural analysis from bulk samples that underwent non-isothermal heat treatment at different temperatures according to DSC crystallization peak. (AU) | |
| FAPESP's process: | 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass |
| Grantee: | Edgar Dutra Zanotto |
| Support Opportunities: | Research Grants - Research, Innovation and Dissemination Centers - RIDC |