Understanding the improved stability and reduced thermal conductivity of yttria stabilized zirconia: A combined experimental and atomistic modeling study

Abstract

Y2O3 is often utilized to stabilize zirconia and reduce the thermal conductivity. However, the phenomena of improved stability and thermal insulation properties are not clarified yet. In this paper, different compensated and non-compensated 8YSZ systems are modeled and simulated using density functional theory (DFT). 8YSZ coatings with different processing parameters are prepared by atmospheric plasma spray (APS) technique to verify the theoretical findings. Moreover, a qualitative and quantitative relationship between the microstructure and thermal conductivity is developed. Based on the phonon scattering, the substitutional point defect (Y3+ dopant) plus oxygen vacancies are responsible for the improved stability and reduced thermal conductivity. Electron back scattered diffraction analysis verifies the molecular dynamics simulations results. Thermal conductivity values estimated from the calculations are consistent with the experimental observations.