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Pierre LucasUniversity of ArizonaStructure And Dynamics Of Tetrahedral Ionic Glass-forming Liquids Angell International Symposium on Molten Salt, Ionic & Glass-forming Liquids: Processing and Sustainability (7th Intl. Symp. on Molten Salt, Ionic & Glass-forming Liquids: Processing and Sustainability). Back to Plenary Lectures » |
Abstract:Molten halide salts are of interest for applications as heat transport fluids (HTF) in concentrated solar power plants due to their excellent resilience at high temperatures. Application as HTF requires a combination of properties including high heat capacity, low vapor pressure and low viscosity to optimize fluid flow through heat-exchanger networks. A fundamental understanding of viscous behavior in halide salts in relation to their structure is therefore of interest for optimizing HTF formulations. Here we perform a combination of modeling (ab-initio molecular dynamics) [1] and spectroscopic analysis (Raman) [2] of tetrahedral zinc chloride melts as a function of temperature. It is found that the ratio of edge- to corner-sharing tetrahedra varies with temperature and that it can be correlated with the viscous behavior through configurational entropy considerations. More interestingly, it is observed that a fragile-to-strong transition occurs at high temperature which can also be correlated with a change in structural behavior [3]. This behavior is compared with that of other tetrahedral melts and found to be related to changes in multiple physical properties such as heat-capacity, density, compressibility etc. References:[1] A.Q. Alsayoud, M. Venkateswara Rao, A.N. Edwards, P.A. Deymier, K. Muralidharan, B.G. Potter, K. Runge, P. Lucas, Structure of ZnCl2 Melt. Part I: Raman Spectroscopy Analysis Driven by Ab Initio Methods, J. Phys. Chem. B, 120 (2016) 4174-4181. |
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