Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses

Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses

Differential thermal analysis and scanning electron microscopy were used to determine the influence of the addition of BaO on the crystallization mechanism of Li2O-ZrO2-SiO2 systems. As the concentration of BaO in the samples increased, a transition occurred in the predominant crystallization mechanism, which passed from superficial to volumetric. To determine the maximum nucleation rate, the crystallization kinetics of the sample containing 20 mole % BaO, which showed the most uniform crystallization, was studied by counting the nuclei with an image analyzer. The first nuclei appeared at the first endothermic inflection point (at the start of Tg, at 440 °C), while the maximum number of nuclei was counted at the midpoint of the glass transition region (446 °C). These results are similar to those observed for other materials that crystallize in volume, and confirm scanning electron microscopy data.

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Main Authors: Silveira,Cristian Berto da, Campos,Sílvia Denofre de, Campos,Elvio A. de, Oliveira,Antônio Pedro Novaes de
Format: Digital revista
Language:English
Published: ABM, ABC, ABPol 2002
Online Access:http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392002000100004
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spelling oai:scielo:S1516-143920020001000042004-10-20Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 GlassesSilveira,Cristian Berto daCampos,Sílvia Denofre deCampos,Elvio A. deOliveira,Antônio Pedro Novaes de glass ceramics barium oxide crystallization Li2O-ZrO2-SiO2 glass Differential thermal analysis and scanning electron microscopy were used to determine the influence of the addition of BaO on the crystallization mechanism of Li2O-ZrO2-SiO2 systems. As the concentration of BaO in the samples increased, a transition occurred in the predominant crystallization mechanism, which passed from superficial to volumetric. To determine the maximum nucleation rate, the crystallization kinetics of the sample containing 20 mole % BaO, which showed the most uniform crystallization, was studied by counting the nuclei with an image analyzer. The first nuclei appeared at the first endothermic inflection point (at the start of Tg, at 440 °C), while the maximum number of nuclei was counted at the midpoint of the glass transition region (446 °C). These results are similar to those observed for other materials that crystallize in volume, and confirm scanning electron microscopy data.info:eu-repo/semantics/openAccessABM, ABC, ABPolMaterials Research v.5 n.1 20022002-03-01info:eu-repo/semantics/articletext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392002000100004en10.1590/S1516-14392002000100004
institution SCIELO
collection OJS
country Brasil
countrycode BR
component Revista
access En linea
databasecode rev-scielo-br
tag revista
region America del Sur
libraryname SciELO
language English
format Digital
author Silveira,Cristian Berto da
Campos,Sílvia Denofre de
Campos,Elvio A. de
Oliveira,Antônio Pedro Novaes de
spellingShingle Silveira,Cristian Berto da
Campos,Sílvia Denofre de
Campos,Elvio A. de
Oliveira,Antônio Pedro Novaes de
Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses
author_facet Silveira,Cristian Berto da
Campos,Sílvia Denofre de
Campos,Elvio A. de
Oliveira,Antônio Pedro Novaes de
author_sort Silveira,Cristian Berto da
title Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses
title_short Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses
title_full Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses
title_fullStr Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses
title_full_unstemmed Crystallization Mechanism and Kinetics of BaO-Li2O-ZrO2-SiO2 Glasses
title_sort crystallization mechanism and kinetics of bao-li2o-zro2-sio2 glasses
description Differential thermal analysis and scanning electron microscopy were used to determine the influence of the addition of BaO on the crystallization mechanism of Li2O-ZrO2-SiO2 systems. As the concentration of BaO in the samples increased, a transition occurred in the predominant crystallization mechanism, which passed from superficial to volumetric. To determine the maximum nucleation rate, the crystallization kinetics of the sample containing 20 mole % BaO, which showed the most uniform crystallization, was studied by counting the nuclei with an image analyzer. The first nuclei appeared at the first endothermic inflection point (at the start of Tg, at 440 °C), while the maximum number of nuclei was counted at the midpoint of the glass transition region (446 °C). These results are similar to those observed for other materials that crystallize in volume, and confirm scanning electron microscopy data.
publisher ABM, ABC, ABPol
publishDate 2002
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392002000100004
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