Abstract
Chemically homogeneous amorphous powders were prepared by sol-gel method from alkoxide mixtures in the silica-rich region of the alumina-silica-zirconia system. A glass with the same composition was obtained by quenching in water from the melt. The evolution with temperature in the range up to 1625 °C was studied by means of X-ray diffraction, infrared and UV-Raman spectroscopy, scanning electron microscopy and energy-dispersive X-ray analysis. Zircon crystallization and stability at temperatures higher than the liquidus temperature were confirmed in both melt-quenched and gel-glasses. Crystallization of cristobalite from the amorphous gel-glasses was observed above 1200 °C. The crystallization of zircon particles was observed after thermal treatment at 1550 °C. At 1625 °C zircon was the only stable crystalline phase due to the complete melting of the silica-rich matrix. The XRD pattern of the ternary gel treated at 1625 °C shows clearly the disappearance of the cristobalite phase, while at 1550 °C there is already partial melting. These results can help to determine the phase equilibrium in the ternary system.
Original language | English |
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Pages (from-to) | 5663-5669 |
Number of pages | 7 |
Journal | Journal of Non-Crystalline Solids |
Volume | 352 |
Issue number | 52-54 |
DOIs | |
Publication status | Published - 2006 Dec 15 |
Keywords
- Crystallization
- FTIR measurements
- Optical properties
- Oxidation reduction
- Oxide glasses
- Phases and equilibria
- Raman spectroscopy
- Silica
- Sol-gel, aerogel and solution chemistry
- Solution chemistry
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry