Thermal conductivity of halide solid solutions: measurement and prediction

Area of Science:

• Materials Science
• Solid-State Physics
• Thermodynamics

Background:

• Lattice thermal conductivity is crucial for materials performance.
• Understanding its behavior in solid solutions is complex.
• NaCl-KCl solid solutions serve as a model system.

Purpose of the Study:

• To measure the composition and temperature dependence of lattice thermal conductivity in NaCl-KCl solid solutions.
• To develop and validate a theoretical model for predicting thermal conductivity in these systems.
• To establish a general method for predicting thermal conductivity in halide solid solutions.

Main Methods:

• Preparation of NaCl-KCl solid solution samples with varied compositions.
• Measurement of thermal diffusivity using the laser flash technique (373 K - 823 K).
• Application of a theoretical model based on the Debye approximation of phonon density of state.

Main Results:

• Experimental data on lattice thermal conductivity as a function of composition and temperature were obtained.
• The theoretical model accurately predicted the thermal conductivity for both stoichiometric compounds and disordered solid solutions.
• Excellent agreement was observed between the model predictions and experimental measurements.

Conclusions:

• The developed theoretical model effectively predicts lattice thermal conductivity in NaCl-KCl solid solutions.
• The findings provide a reliable method for estimating thermal conductivity in various halide systems.
• This research contributes to the understanding of thermal transport in mixed ionic crystals.