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Simulation and experimental study of the particle size distribution and pore effect on the crystallization of glass powders

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Autor(es):
Fernandes, Roger G. [1] ; Reis, Raphael M. C. V. [2] ; Tobar, Raul R. [1] ; Zanotto, Edgar D. [3] ; Ferreira, Eduardo B. [1]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Sao Carlos Sch Engn, Dept Mat Engn, 400 Trabalhador Sao Carlense Ave, BR-13566590 Sao Carlos, SP - Brazil
[2] Fluminense Fed Univ, UFF, Dept Met & Mat Engn, 420 Trabalhadores Ave, BR-27255125 Volta Redonda, RJ - Brazil
[3] Univ Fed Sao Carlos, UFSCar, Dept Mat Engn, Vitreous Mat Lab, Washington Luis Rd, Km 235, BR-13565905 Sao Carlos, SP - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: ACTA MATERIALIA; v. 175, p. 130-139, AUG 15 2019.
Citações Web of Science: 0
Resumo

Surface nucleation is a frequent phenomenon and plays an essential role in the crystallization of most glasses, especially glass powders used in sintered glass-ceramics, for example. A technique often employed to study the crystallization kinetics of glassy powders is Differential Scanning Calorimetry (DSC). However, the shape of the crystallization peak profile is usually very complex. For instance, in certain cases of surface nucleation, the crystal growth dimensionality may change during crystallization after crystal impingement, and a large density difference between the parent glass and the resulting crystalline phases may produce cavitation pores in the particle volume. Finally, crushed glass particles are not regularly shaped, as assumed in most models. Hence, to evaluate the crystallization kinetics of glass powders by DSC experiments, in this work, we modified and tested a particle crystallization model using the DSC crystallization peaks of jagged powders of a non-stoichiometric (0.95CaO center dot 0.73MgO center dot 2SiO(2)) diopside glass having different granulometries and a large crystal/glass density difference. The Reis-Zanotto model was adapted to include two complex variables: particle size distribution and crystallization-induced porosity. As predicted by the modified model, we confirmed the radical change of the DSC peak shape for some particle sizes as a result of crystal impingement and pore formation. This combined experimental-simulation study demonstrates that the adapted model can describe this type of complex and yet frequent crystallization case. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. (AU)

Processo FAPESP: 13/09234-4 - Estudo do fator de forma de partículas de vidros para sinterização através da cinética de cristalização determinada por calorimetria exploratória diferencial (DSC)
Beneficiário:Roger Gomes Fernandes
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
Beneficiário:Edgar Dutra Zanotto
Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs