Thermal conductivity of halide solid solutions: Measurement and prediction

Abstract

The composition dependence of the lattice thermal conductivity in NaCl-KCl solid solutions has been measured as a function of composition and temperature. Samples with systematically varied compositions were prepared and the laser flash technique was used to determine the thermal diffusivity from 373 K to 823 K. A theoretical model, based on the Debye approximation of phonon density of state (which contains no adjustable parameters) was used to predict the thermal conductivity of both stoichiometric compounds and fully disordered solid solutions. The predictions obtained with the model agree very well with our measurement. A general method for predicting the thermal conductivity of different halide systems is discussed.

Thermal transport properties of halide solid solutions: Experiments vs equilibrium molecular dynamics

“…tion as functions of temperature and composition. The EMD prediction of the thermal conductivity of pure NaCl at 900 K is in very good agreement with the critically assessed value reported by Gheribi et al, 17 with a di↵erence of about 5%. Unlike the NaCl case, the accuracy of about 25% obtained for KCl is relatively poor.…”

“…For all compositions, we have observed that (⌧) reaches a plateau before 10 ps and the thermal conductivity values were calculated by averaging (⌧) for ⌧ 10 ps. 17 The EMD simulations (filled stars symbols) have been performed only at 900 K. The critically assessed values 17 of the thermal conductivity of pure NaCl and KCl compounds at 900 K are also reported (filled square). Point interpolation were splined (dashed lines).…”

“…It is rather more suitable to refer to the thermal conductivity degradation as proposed in a prior work. 17 The thermal conductivity degradation, D , is a measure of the relative deviation from a linear dependence of with x and is defined as The thermal conductivity degradation is a proper way to define the composition-thermal conductivity relationship. Such a definition clearly points out the strong deviation from the linearity of the thermal transport properties relations.…”

“…The experimental thermal conductivity of the (Na,K)Cl rocksalt solid solution as a function of both temperature and composition has already been presented in a previous work. 17 FIG. 1.…”

“…1. The coherent NaCl-KCl phase diagram along with the set of composition-temperature points for which the thermal di↵usivity has been measured by laser flash method 17 (solid red square) and calculated by EMD simulations (solid blue circle). Outside the miscibility gap, the SS is stable and inside the miscibility gap, phase separation into two distinct solid solutions SS1 and SS2 occurs.…”