Ceramics-Silikáty 57, (1) 66 - 73 (2013) |
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THERMODYNAMIC MODEL AND VISCOSITY OF SELECTED ZIRCONIA CONTAINING SILICATE GLASSES
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Chromčíková Mária, Liška Marek, Gašpáreková Eleonóra,
Teplanová Magdaléna,
Karell Radovan
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Vitrum Laugaricio – Joint Glass Center of the Institute of Inorganic Chemistry, Slovak Academy of Sciences,
Alexander Dubček University of Trenčín, Faculty of Chemical and Food Technology, Slovak Technical University,
and RONA, j.s.c., Študentská 2, 911 01 Trenčín, Slovak Republic
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Keywords: Zirconia-silicate glasses, Thermodynamic model, Viscosity, Property-composition relationships
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The compositional dependence of viscosity, and viscous flow activation energy of glasses with composition xNa2O∙(15-x)
K2O∙yCaO∙(10-y)ZnO∙zZrO2∙(75-z)SiO2 (x = 0, 7.5, 15; y = 0, 5, 10; z = 0, 1, 3, 5, 7) was analyzed. The studied glasses
were described by the thermodynamic model of Shakhmatkin and Vedishcheva considering the glass as an equilibrium ideal
solution of species with stoichiometry given by the composition of stable crystalline phases of respective glass forming
system. Viscosity-composition relationships were described by the regression approach considering the viscous flow
activation energy and the particular isokome temperature as multilinear function of equilibrium molar amounts of system
components. The classical approach where the mole fractions of individual oxides are considered as independent variables
was compared with the thermodynamic model. On the basis of statistical analysis there was proved that the thermodynamic
model is able to describe the composition property relationships with higher reliability. Moreover, due its better physical
justification, thermodynamic model can be even used for predictive purposes. |
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