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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2002
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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 |
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Silveira,Cristian Berto da Campos,Sílvia Denofre de Campos,Elvio A. de Oliveira,Antônio Pedro Novaes de |
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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 |
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Silveira,Cristian Berto da Campos,Sílvia Denofre de Campos,Elvio A. de Oliveira,Antônio Pedro Novaes de |
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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. |
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ABM, ABC, ABPol |
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2002 |
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http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392002000100004 |
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1756420265807446016 |