| Autor: |
Weber, Richard, Benmore, Chris J., Siewenie, Joan, Urquidi, Jacob, Key, Thomas S. |
| Zdroj: |
Physical Chemistry Chemical Physics (PCCP); 2004, Vol. 6 Issue: 9 p2480-2483, 4p |
| Abstrakt: |
Pulsed neutron and high energy X-ray diffraction experiments on single- and two-phase Al2O3–Y2O3and single-phase Al2O3–La2O3glasses suggest that a polyamorphic phase transition occurs viachanges in the Y–O coordination and connectivity. The transformation from a high temperature to a low temperature amorphous phase is mainly associated with the formation of YO8polyhedra at the expense of YO7polyhedra. The transition produces a more ordered network structure with increased oxygen connectivity, while maintaining the overall metaloxygen stoichiometry. It is estimated that for the two-phase sample studied ∼12 of the Y ions had transformed to the higher coordinate form in the supercooled liquid as the onset of the glass transition was reached. |
| Databáze: |
Supplemental Index |
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