Ultra-low lattice thermal conductivity in tungsten-based scheelite ceramics

Hicham Ait Laasri; Eliane Bsaibess; Fabian Delorme; Guillaume F. Nataf; Fabien Giovannelli

doi:10.1016/j.jallcom.2023.170167

paper

Ultra-low lattice thermal conductivity in tungsten-based scheelite ceramics

arXiv:2305.09576 · doi:10.1016/j.jallcom.2023.170167

Abstract

$B aW O_{4}$ , $C e_{2/3} □_{1/3} W O_{4}$ and $L a_{2/3} □_{1/3} W O_{4}$ polycrystalline ceramics were synthesized by conventional solid-state reaction route. The effect of cation-deficiency on the crystallographic structure, microstructure and thermal properties of these scheelite-type compounds were investigated. X-ray diffraction was used to identify the single-phase scheelite structure of the studied ceramics. Scanning Electron Microscopy technique has revealed a homogenous and dense microstructure with a few micro-cracks. The thermal conductivity of $B aW O_{4}$ scheelite decreases from $1.3 \pm 0.2$ to $1.0 \pm 0.1 W m^{- 1} K^{- 1}$ in the range 373 K - 673 K. The cation-deficient scheelites $C e_{2/3} □_{1/3} W O_{4}$ and $L a_{2/3} □_{1/3} W O_{4}$ ceramics display an ultra-low thermal conductivity of $0.3 \pm 0.04 W m^{- 1} K^{- 1}$ and $0.2 \pm 0.03 W m^{- 1} K^{- 1}$ at 673 K, respectively. These materials exhibit among the lowest known values of thermal conductivity in crystalline oxides, in this temperature range. Therefore, they appear as very attractive for thermal barrier coating and thermoelectric applications.

18 pages, 4 figures

References in corpus (1)

Glass-like thermal conductivity in SrTiO3 thermoelectrics induced by A-site vacancies