Effect of CaF 2 , B 2 O 3 and the CaO/SiO 2 mass ratio on the viscosity and structure of B 2 O 3 -containing calcium-silicate-based melts

Gi Hyun Kim, Il Sohn

Research output: Contribution to journalArticle

Abstract

The relationship between the viscosity and structure of B 2 O 3 -containing calcium-silicate-based mold fluxes and the effects of fluidizers including CaF 2 , CaO, and B 2 O 3 on the viscosity and their correlation with the structural aspects were studied using a rheometer with Fourier transformation infrared and Raman spectroscopy. The viscosity decreased with increasing CaF 2 addition up to 28 wt% at a fixed CaO/SiO 2 ratio of 0.3, which was related to depolymerization. Furthermore, CaF 2 addition also affected the apparent activation energy for viscous flow, which decreased with increasing CaF 2 content to 105.1 from 151.1 kJ/mol. At higher C/S ratios, the viscosity decreased in the presence of greater Ca 2+ and O 2− supplied from CaO, which subsequently increased the activation energy to 149.7 from 122.0 kJ/mol. With regard to the B 2 O 3 -melt, polymerization of the network structure was observed by comparing the B 2 O 3 -free to 4.4 wt% B 2 O 3 content. However, the viscosity was relatively constant with increasing B 2 O 3 addition. However, the viscosity decreased due to greater simplification of the network structure above 4.4 wt% B 2 O 3 . The break temperature decreased with greater B 2 O 3 addition as the crystallization was inhibited. Furthermore, the apparent activation energy decreased as depolymerization of the network structures occurred above 4.4 wt% B 2 O 3 .

Original languageEnglish
JournalJournal of the American Ceramic Society
DOIs
Publication statusPublished - 2019 Jan 1

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Calcium silicate
Viscosity
Depolymerization
Activation energy
Rheometers
Viscous flow
Crystallization
Raman spectroscopy
calcium silicate
Infrared spectroscopy
Polymerization
Fluxes

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

Cite this

@article{e456f103ae324374a36fe828373012df,
title = "Effect of CaF 2 , B 2 O 3 and the CaO/SiO 2 mass ratio on the viscosity and structure of B 2 O 3 -containing calcium-silicate-based melts",
abstract = "The relationship between the viscosity and structure of B 2 O 3 -containing calcium-silicate-based mold fluxes and the effects of fluidizers including CaF 2 , CaO, and B 2 O 3 on the viscosity and their correlation with the structural aspects were studied using a rheometer with Fourier transformation infrared and Raman spectroscopy. The viscosity decreased with increasing CaF 2 addition up to 28 wt{\%} at a fixed CaO/SiO 2 ratio of 0.3, which was related to depolymerization. Furthermore, CaF 2 addition also affected the apparent activation energy for viscous flow, which decreased with increasing CaF 2 content to 105.1 from 151.1 kJ/mol. At higher C/S ratios, the viscosity decreased in the presence of greater Ca 2+ and O 2− supplied from CaO, which subsequently increased the activation energy to 149.7 from 122.0 kJ/mol. With regard to the B 2 O 3 -melt, polymerization of the network structure was observed by comparing the B 2 O 3 -free to 4.4 wt{\%} B 2 O 3 content. However, the viscosity was relatively constant with increasing B 2 O 3 addition. However, the viscosity decreased due to greater simplification of the network structure above 4.4 wt{\%} B 2 O 3 . The break temperature decreased with greater B 2 O 3 addition as the crystallization was inhibited. Furthermore, the apparent activation energy decreased as depolymerization of the network structures occurred above 4.4 wt{\%} B 2 O 3 .",
author = "Kim, {Gi Hyun} and Il Sohn",
year = "2019",
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language = "English",
journal = "Journal of the American Ceramic Society",
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T1 - Effect of CaF 2 , B 2 O 3 and the CaO/SiO 2 mass ratio on the viscosity and structure of B 2 O 3 -containing calcium-silicate-based melts

AU - Kim, Gi Hyun

AU - Sohn, Il

PY - 2019/1/1

Y1 - 2019/1/1

N2 - The relationship between the viscosity and structure of B 2 O 3 -containing calcium-silicate-based mold fluxes and the effects of fluidizers including CaF 2 , CaO, and B 2 O 3 on the viscosity and their correlation with the structural aspects were studied using a rheometer with Fourier transformation infrared and Raman spectroscopy. The viscosity decreased with increasing CaF 2 addition up to 28 wt% at a fixed CaO/SiO 2 ratio of 0.3, which was related to depolymerization. Furthermore, CaF 2 addition also affected the apparent activation energy for viscous flow, which decreased with increasing CaF 2 content to 105.1 from 151.1 kJ/mol. At higher C/S ratios, the viscosity decreased in the presence of greater Ca 2+ and O 2− supplied from CaO, which subsequently increased the activation energy to 149.7 from 122.0 kJ/mol. With regard to the B 2 O 3 -melt, polymerization of the network structure was observed by comparing the B 2 O 3 -free to 4.4 wt% B 2 O 3 content. However, the viscosity was relatively constant with increasing B 2 O 3 addition. However, the viscosity decreased due to greater simplification of the network structure above 4.4 wt% B 2 O 3 . The break temperature decreased with greater B 2 O 3 addition as the crystallization was inhibited. Furthermore, the apparent activation energy decreased as depolymerization of the network structures occurred above 4.4 wt% B 2 O 3 .

AB - The relationship between the viscosity and structure of B 2 O 3 -containing calcium-silicate-based mold fluxes and the effects of fluidizers including CaF 2 , CaO, and B 2 O 3 on the viscosity and their correlation with the structural aspects were studied using a rheometer with Fourier transformation infrared and Raman spectroscopy. The viscosity decreased with increasing CaF 2 addition up to 28 wt% at a fixed CaO/SiO 2 ratio of 0.3, which was related to depolymerization. Furthermore, CaF 2 addition also affected the apparent activation energy for viscous flow, which decreased with increasing CaF 2 content to 105.1 from 151.1 kJ/mol. At higher C/S ratios, the viscosity decreased in the presence of greater Ca 2+ and O 2− supplied from CaO, which subsequently increased the activation energy to 149.7 from 122.0 kJ/mol. With regard to the B 2 O 3 -melt, polymerization of the network structure was observed by comparing the B 2 O 3 -free to 4.4 wt% B 2 O 3 content. However, the viscosity was relatively constant with increasing B 2 O 3 addition. However, the viscosity decreased due to greater simplification of the network structure above 4.4 wt% B 2 O 3 . The break temperature decreased with greater B 2 O 3 addition as the crystallization was inhibited. Furthermore, the apparent activation energy decreased as depolymerization of the network structures occurred above 4.4 wt% B 2 O 3 .

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