Critical assessment of DTA-DSC methods for the study of nucleation kinetics in glasses

Autor(es)

Fokin, Vladimir M. ^[1] ; Cabral, Aluisio A. ; Reis, Raphael M. C. V. ^[2] ; Nascimento, Marcio L. F. ^[2] ; Zanotto, Edgar D. ^[2]

Afiliação do(s) autor(es)

^[1] SI Vavilovs State Opt Inst, St Petersburg 193171 - Russia

^[2] Univ Fed Sao Carlos, DEMa, Vitreous Mat Lab LaMaV, BR-13560 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Non-Crystalline Solids; v. 356, n. 6-8, p. 358-367, MAR 1 2010.
• Citações Web of Science: 44

Resumo

Microscopy methods are usually employed to estimate the number density of super critical nuclei and the resulting crystal nucleation rates, I(T). These traditional techniques rely on a double-stage treatment, i.e. the development of the nuclei at a temperature higher than the previous nucleation temperature up to a size large enough to be visible with optical or electron microscopy. These methods can give reliable results for I(T), but are rather laborious and time-consuming. On the other hand, non-isothermal (DTA/DSC) methods are, in principle, much faster. In this paper, we experimentally test two non-isothermal methods by comparison with a traditional optical microscopy method. We found that, if they are properly employed, non-isothermal methods can give useful kinetic information, which includes the crystal number density and nucleation rates, but to get accurate quantitative data they need some preliminary information about nucleation and growth rates in the studied glass and, in addition, are as laborious as the traditional microscopy methods! (C) 2009 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 08/00475-0 - Vladimir Mikhailovich Fokin | S.I. Vavilov State Optical Institute - Rússia
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional
• Processo FAPESP: 07/08179-9 - Processos cinéticos em vidros e vitrocerâmicas
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Temático