Size and temperature dependence of intrinsic thermal conductivity in bulk 8YSZ: An RNEMD study

Thermal barrier coatings (TBCs) has been extensively applied in aircraft engines and gas turbines to reduced heat transfer between hot gas and the metal. As a typical ceramic top-coat material, yttria-stabilized zirconia (YSZ) has attracted widespread attention due to its excellent high-temperature stability and low thermal conductivity. In this study, reverse non-equilibrium molecular dynamics (RNEMD) simulations were employed to calculate the thermal conductivity of 8 mol% yttria-stabilized zirconia (8YSZ) and to investigate the effects of temperature and size dependence. Thermal conductivity was evaluated over the service-relevant temperature range of 1173∼1473 K with 100 K increments using model with different lengths. The results indicate that 8YSZ exhibits low thermal conductivity within the investigated temperature range, with values affected by model size. Thermal conductivity decreases with increasing temperature, while the rate of reduction gradually diminishes. The prediction trends agree well with experimental results, suggesting the reliability of the proposed method.