Atomistic and experimental study on thermal conductivity of bulk and porous cerium dioxide

Abstract

Cerium dioxide (CeO 2 ) is a surrogate material for traditional nuclear fuels and an essential material for a wide variety of industrial applications both in its bulk and nanometer length scale. Despite this fact, the underlying physics of thermal conductivity ( k L ), a crucial design parameter in industrial applications, has not received enough attention. In this article, a systematic investigation of the phonon transport properties was performed using ab initio calculations unified with the Boltzmann transport equation. An extensive examination of the phonon mode contribution, available three-phonon scattering phase space, mode Grüneisen parameter and mean free path (MFP) distributions were also conducted. To further augment theoretical predictions of the k L , measurements were made on specimens prepared by spark plasma sintering using the laser flash technique. Since the sample porosity plays a vital role in the value of measured k L , the effect of porosity on k L by molecular dynamics (MD) simulations were investigated. Finally, we also determined the nanostructuring effect on the thermal properties of CeO 2 . Since CeO 2 films find application in various industries, the dependence of thickness on the in-plane and cross-plane k L for an infinite CeO 2 thin film was also reported.

Impact of irradiation induced dislocation loops on thermal conductivity in ceramics

“…Additionally, phonon lifetime measurements using neutron scattering supplemented by first principles calculations in UO 2 suggested that optical modes also contribute to thermal transport in materials with the fluorite crystalline structure . Recent atomic level conductivity calculations have confirmed similar behavior in CeO 2 . More accurate analysis using actual phonon dispersion will require reformulation of the phonon‐defect scattering rates for each phonon mode, but will not significantly change the conclusion of this work …”

“…The dislocation line model, which only includes the contribution from the extended strain field, is given bywhere γ ‐Gruneisen parameter, b ‐dislocation line Burgers vector, and N d ‐dislocation line density, defined as the number of lines per unit area, . Here, we use γ = 2.05 obtained from atomistic calculation of thermal conductivity in CeO 2 . While the scattering from platelet inclusion is:…”

“…69 Recent atomic level conductivity calculations have confirmed similar behavior in CeO 2 . 63 More accurate analysis using actual phonon dispersion will require reformulation of the phonon-defect scattering rates for each phonon mode, but will not significantly change the conclusion of this work. 1 These results provide a validation for one controversial observation that can be obtained from classical thermal transport models using relaxation time expression summarized by Klemens.…”

“…Here, we use γ = 2.05 obtained from atomistic calculation of thermal conductivity in CeO 2 . 63 While the scattering from platelet inclusion is 14 : Lastly, the scattering by stacking faults is given by 59 :…”

The effect of finite-temperature and anharmonic lattice dynamics on the thermal conductivity of ZrS2 monolayer: self-consistent phonon calculations

“…In ZrS2 ML system, the three-phonon SPS at 300 K increases upon increasing the phonon frequency (above 160 cm -1 as shown in Fig. S2, Supplemental Material [68]), which correspond to the subsequently lower 𝜅 9 [71,72] thereby increasing the scattering channels. The three phonon SPS values for absorption processes at 300 K reach to its minimum at higher frequencies (Fig.…”