Application of environmental relaxation model to the transport behavior of glass‐forming melts

Abstract

SynopsisThe environmental relaxation model was applied successfully to explain the temperature dependence of viscosity, conductance, and the Walden product of molten Ca(N0&-3.91H20 + NiCI:! system in the non-Arrhenius region. This model was applied to pure melts, binary molten salt systems with ideal solutions marked by the absence of complex ions, and systems in which octahedral or tetrahedral complexes are formed. The values of the glass transition temperature obtained from the free volume and environmental relaxation models are in good agreement. The values of apparent activation energies for viscous and conductance flows derived from these two models are also comparable.Arrhenius region. The molten Ca(N03)2-3.91HzO + NiCl2 system was chosen for a detailed study of the applicability of ERM. Ni2+ forms an octahedral complex species, Ni(H20)&12, in molten calcium nitrate tetrahydrate.6 The reported viscosities 7 and equivalent conductances A of this system in the temperature range 298-343 K and composition range 0.0-6.49 mole % of Ni2+ (the maximum solubility of anhydrous NiCl2 in molten calcium nitrate tetrahydrate) were considered here for data analysis. This analysis was also made for pure melt, ideal molten salt mixture, and nonideal melts that contain octahedral or tetrahedral complex ions.