| Full text | |
| Author(s): |
Total Authors: 5
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| Affiliation: | [1] Tech Univ Clausthal, Inst Nonmetall Mat, Zehntner Str 2A, D-38678 Clausthal Zellerfeld - Germany
[2] Univ Fed Sao Carlos, Ctr Res Technol & Educ Vitreous Mat CeRTEV, BR-565905 Sao Carlos, SP - Brazil
Total Affiliations: 2
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| Document type: | Journal article |
| Source: | Journal of Non-Crystalline Solids; v. 474, p. 1-8, OCT 15 2017. |
| Web of Science Citations: | 6 |
| Abstract | |
Nucleation kinetics of glass-ceramics is frequently determined using Tammann's double-stage heat-treatment. This method requires a complex deconvolution of the experimentally observed induction time (t(ind)), i.e. the intercept of the linear part of the crystal number density curve with the nucleation time axis, into two components. In this paper, double-stage heat treatments were performed, with heating rates between the nucleation and development temperatures covering two orders of magnitude, in samples of a homogeneously nucleating glass-forming system, lithium disilicate. Our results show that t(ind) increases with increasing heating rates with cubic root dependence. In accordance with the theory, t(ind) was split into the intrinsic time required to establish a steady-state cluster size distribution, tau (time-lag) at the nucleation temperature and an incubation time (t(i)), which is a size, heating rate and development temperature (T-d) dependent growth time. We demonstrate that the Collins-Kashchiev nucleation model performs poorly if t(i) is approximated by the time needed to experimentally detect the first crystal. In contrast, the Shneidman approach is consistent with theory. We found that at any given nucleation temperature, t(i) is a strong function of the heating rate, and is proportional to t(ind), whereas tau is a constant, as expected. (AU) | |
| FAPESP's process: | 15/13314-9 - Development and Characterization of Tough Bioactive Glass-ceramics |
| Grantee: | Maziar Montazerian |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| 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 |
| FAPESP's process: | 16/11650-4 - Heating rate effects in nucleation of glasses: from lab to practice |
| Grantee: | Edgar Dutra Zanotto |
| Support Opportunities: | Research Grants - Visiting Researcher Grant - International |