Effects of lithium oxide on the crystallization kinetics of Na2O center dot 2CaO center dot 3SiO(2) glass

Autor(es)

Gallo, Leonardo Sant'Ana ^[1] ; Mosca, Tiago De Marchi ^[1] ; Teider, Bruno Henrique ^[1] ; Polyakova, Irina ^[2] ; Martins Rodrigues, Ana Candida ^[1] ; Zanotto, Edgar Dutra ^[1] ; Fokin, Vladimir M. ^[3]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Mat Engn, LaMaV DEMa, Vitreous Mat Lab, BR-13565905 Sao Carlos, SP - Brazil

^[2] Russian Acad Sci, IV Grebenshchikov Silicate Chem Inst, St Petersburg 199155 - Russia

^[3] SI Vavilov State Opt Inst, St Petersburg 193171 - Russia

• Tipo de documento: Artigo Científico
• Fonte: Journal of Non-Crystalline Solids; v. 408, p. 102-114, JAN 15 2015.
• Citações Web of Science: 7

Resumo

The crystal nucleation (1) and growth (U) rates of Na2O center dot 2CaO center dot 3SiO(2) glasses with increasing additions of Li2O were measured for the primary crystalline phase over wide and overlapping temperature intervals. A partial section of the phase diagram Na2O center dot 2CaO center dot 3SiO(2)-Li2O was constructed via DSC analysis and shows a narrow range of solid solution formation that is close to that of Na2O center dot 2CaO center dot 3SiO(2). In the four-component system (Na2O-Li2O-CaO-SiO2), a pseudo-binary eutectic system of Na2O center dot 2CaO center dot 3SiO(2)-Li2O center dot SiO2 exists. The role of Li2O in the formation of the crystalline phases was investigated using DSC and X-ray analyses. The addition of Li2O results in decreases in the glass transition (T-g) and liquidus (T-L) temperatures. With increasing Li2O content, both the reduced glass transition temperature T-gr (T-gr = T-g/T-L) and the fragility index, m, pass through a minimum. These findings extend and confirm the known inverse correlation between T-gr and I-max, (lower values of T-g, correspond to higher values of I-max) and provide evidence for a similar correlation between m and I-max. When using the low temperature data for the crystal growth rate (U) the viscosity (eta) and diffusivity (D) were decoupled at T< 1.1 T-g. Next, a parameter (U center dot eta at T-g) that characterized the decoupling phenomenon was proposed. (c) 2014 Elsevier B.V. All rights reserved. (AU)

• 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