Molecular dynamics simulation of Sc2O3-Gd2O3-Y2O3 dopant effect on the crystal structure and thermophysical properties of zirconia-based ceramic materials

Abstract

This paper aims to provide an insight into the effects of different doping ratios on the crystal structure, thermal conductivity, ion diffusion, and high-temperature thermal expansion coefficient of Sc2O3-Gd2O3-Y2O3 co-doped ZrO2 (ScGdYSZ) materials. They were investigated by a non-equilibrium molecular dynamics method. The results show that with Gd2O3-Sc2O3-Y2O3 co-doping, the thermal expansion of the resulting materials is all relatively close to that of 8YSZ materials and linear with temperature. At 1473 K, 1 mol%Sc2O3–3 mol%Gd2O3–4 mol%Y2O3 stabilized ZrO2 (1Sc3Gd4YSZ) coating material has the smallest thermal conductivity, with a thermal conductivity of 5.66 W·(m·K)−1. The mean square displacement (MSD) of O2− was linear with the time when the sum of the doping ratio of Sc2O3 and Gd2O3 was 4 mol%, and the MSD of O2− in the material increased with the doping ratio of Sc2O3. increases, the MSD of O2− in the material increases, and the migration diffusion rate is accelerated.