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Off-stoichiometry effects on crystal nucleation and growth kinetics in soda-lime-silicate glasses. The combeite (Na2O center dot 2CaO center dot 3SiO(2)) - devitrite (Na2O center dot 3CaO center dot 6SiO(2)) joint

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Autor(es):
Macena, Guilherme S. [1] ; Abyzov, Alexander S. [2, 3] ; Fokin, Vladimir M. [1] ; Zanotto, Edgar D. [2] ; Ferreira, Eduardo B. [1]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Sao Carlos Sch Engn, Sao Carlos, SP - Brazil
[2] Univ Fed Sao Carlos, Ctr Res Technol & Educ Vitreous Mat, Dept Mat Engn, Sao Carlos, SP - Brazil
[3] Natl Sci Ctr Kharkov Inst Phys & Technol, Kharkov - Ukraine
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: ACTA MATERIALIA; v. 196, p. 191-199, SEP 1 2020.
Citações Web of Science: 0
Resumo

To the present date, the vast majority of fundamental studies on glass crystallization has been carried out using stoichiometric compositions, whereas by far, the most common cases in glass technology are off-stoichiometric. In this work, we performed a comprehensive study on the nucleation and growth kinetics of combeite crystals in non-stoichiometric glasses of the combeite (Na2O center dot 2CaO center dot 3SiO(2)) - devitrite (Na2O center dot 3CaO center dot 6SiO(2)) system. Using cluster-size distribution functions based on a previously developed kinetic model of nucleation, we constructed the dependencies of the number N(T) of nucleated and grown crystals on the nucleation time, t, and estimated the nucleation rates, I(T) = dN(T)/dt. We then cross-checked the theoretical calculations versus experimental data. In these calculations, the critical nucleus-supercooled liquid specific interfacial energy, sigma, and the effective diffusion coefficient,D, were left as fitting parameters for the best possible description of experimental data. We show that as the precursor glass composition shifts from combeite to devitrite, and thus the difference of composition between the initial glass and the precipitated crystals increases, the interfacial energy increases, and the maximum steady-state nucleation rate, I-St(T-max), of combeite strongly drops. On the other hand, as a consequence of the composition shift, depending on the glass-forming system, the diffusion coefficient may increase or decrease. We also show a significant difference between D estimated from the nucleation experiments and Di, calculated from the growth rates. These results corroborate our previous studies on other systems and are relevant to elucidate the complex mechanisms of crystallization of non-stoichiometric glasses. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. (AU)

Processo FAPESP: 19/02396-5 - Simulações numéricas do efeito da composição e do relaxamento na nucleação de cristais em líquidos formadores de vidro super-resfriados
Beneficiário:Edgar Dutra Zanotto
Linha de fomento: Auxílio à Pesquisa - Pesquisador Visitante - Internacional
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