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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57 Citations (Scopus)

Abstract

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
Volume358
Issue number12-13
DOIs
Publication statusPublished - 2012 Jul 1

All Science Journal Classification (ASJC) codes

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

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