Glass Formation and Structure–Property–Composition Relations of the RE2O3–Al2O3–SiO2 (RE=La, Y, Lu, Sc) Systems

Authors

  • Shahriar Iftekhar,

    1. Physical Chemistry Division, Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
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  • Jekabs Grins,

    1. Inorganic Chemistry Division, Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
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  • Philips N Gunawidjaja,

    1. Physical Chemistry Division, Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
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  • Mattias Edén

    Corresponding author
    1. Physical Chemistry Division, Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm SE-106 91, Sweden
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  • D. J. Green—contributing editor

  • This work was financially supported by the Swedish Research Council (VR; contracts 2007-4967, 2009-7551) and the Faculty of Natural Sciences at Stockholm University. P.N.G. was supported by a postdoctoral grant from the Carl Trygger Foundation.

†Author to whom correspondence should be addressed. e-mail: mattias.eden@mmk.su.se

Abstract

We report the glass-forming regions of the ternary Lu2O3–Al2O3–SiO2 and Sc2O3–Al2O3–SiO2 systems. The density, molar volume, compactness, Vickers hardness, refractive index, as well as the glass transition (Tg) and crystallization temperature are compared for two series of RE–Al–Si–O (RE=La, Y, Lu, Sc) glasses that display a constant molar ratio nAl/nSi=1.00, whereas nRE/nSi is equal to either 0.62 or 0.94. Several glass properties scale roughly linearly with the cation field strength (CFS) of the rare-earth (RE3+) ion, except for the Tg values of the Sc-bearing glasses that are significantly lower than expected. Magic-angle spinning 29Si and 27Al nuclear magnetic resonance (NMR) reveal enhanced network disorder and increased relative populations of AlO5 and AlO6 polyhedra in the aluminosilicate glasses for increasing RE3+ CFS, but overall similar Si and Al local environments (chemical shifts and quadrupolar couplings) in all samples associated with a constant nRE/nSi ratio, except for unexpectedly shielded 29Si NMR signals observed from the Sc–Al–Si–O glasses.

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