Effect of Al 2O 3 on the viscosity and structure of calcium silicate-based melts containing Na 2O and CaF 2

Gi Hyun Kim, Il Sohn

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104 Citations (Scopus)


The effect of Al 2O 3 on viscosity in the calcium silicate melt-based system containing Na 2O and CaF 2 was investigated and correlated with the melt structure using FTIR (Fourier transform infrared) spectroscopy, XPS (X-ray photoelectron spectroscopy), and Raman spectroscopy. Substituting SiO 2 with Al 2O 3 modified the dominant silicate network into a highly structured alumino-silicate structure with the aluminate structure being particularly prevalent at 20 mass% of Al 2O 3 and higher. As the melts become increasingly polymerized with higher Al 2O 3 content, the fraction of symmetric Al-O 0 stretching vibrations significantly increased and the viscosity increased. XPS showed a decrease in the amount of non-bridged oxygen (O -) but an increase in bridged oxygen (O 0) and free oxygen (O 2-) with higher Al 2O 3. Although changes in the structure and viscosity with higher CaO/(SiO 2 + Al 2O 3) were not significant, the symmetric Al-O 0 stretching in the [AlO 4] 5--tetrahedral units decreased. The apparent activation energy for viscous flow varied from 118 to 190 kJ/mol.

Original languageEnglish
Pages (from-to)1530-1537
Number of pages8
JournalJournal of Non-Crystalline Solids
Issue number12-13
Publication statusPublished - 2012 Jul 1

Bibliographical note

Funding Information:
This study was partially supported by the Brain Korea 21 (BK21) Project at the Division of the Humantronics Information Materials, the National Science Foundation of Korea Project No. 2010-8-0581 , and the Ministry of Knowledge Education Project No. 2010-8-0972 .

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Materials Chemistry


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