An Atomistic-Scale Study for Thermal Conductivity and Thermochemical Compatibility in (DyY)Zr2O7 Combining an Experimental Approach with Theoretical Calculation

Abstract

Ceramic oxides that have high-temperature capabilities can be deposited on the superalloy components in aero engines and diesel engines to advance engine efficiency and reduce fuel consumption. This paper aims to study doping effects of Dy3+ and Y3+on the thermodynamic properties of ZrO2 synthesized via a sol-gel route for a better control of the stoichiometry, combined with molecular dynamics (MD) simulation for the calculation of theoretical properties. The thermal conductivity is investigated by the MD simulation and Clarke’s model. This can improve the understanding of the microstructure and thermodynamic properties of (DyY)Zr2O7 (DYZ) at the atomistic level. The phonon-defect scattering and phonon-phonon scattering processes are investigated via the theoretical calculation, which provides an effective way to study thermal transport properties of ionic oxides. The measured and predicted thermal conductivity of DYZ is lower than that of 4 mol % Y2O3 stabilized ZrO2 (4YSZ). It is discovered that DYZ is thermochemically compatible with Al2O3 at 1300 °C, whereas at 1350 °C DYZ reacts with Al2O3 forming a small amount of new phases.

Enhanced doping effects of multielement on anisotropic thermal expansion in ZrO2 with new compositions

“…MD simulation is effective in terms of calculating the dynamic properties of Dy 3+ , Al 3+ , and Ce 4+ ‐doped YSZ based on Newton's second law of motion 20 . It enables the intrinsic transport properties which are sensitive to microstructural features to be calculated without the influence of lattice imperfections 21,22 . Theoretical material properties including the lattice energy and anisotropic CTE are calculated by MD simulation, with an in‐depth understanding on the effects of doping on lattice structure and thermal expansion in ZrO 2 that would greatly facilitate the materials design.…”