Investigation of thermal transport behavior in YSZ and LZ/YSZ coupled system between 1273 and 1473 K using molecular dynamics simulation

Abstract

This paper presents thermal properties in both yttria-stabilized zirconia (YSZ) and the coupled system based on lanthanum zirconate (LZ) and YSZ through molecular dynamics (MD) simulation. Mean square displacement (MSD), thermal transport behavior and thermal conductivity of both YSZ and LZ/YSZ systems were calculated at temperatures ranging from 1273K to 1473K. Typical oxygen ion vibration in both YSZ and LZ/YSZ coupled system were studied. Radial distribution functions (RDFs) of Y ions were investigated in both systems. The oxygen ion hopping in YSZ explains the movements of oxygen ions among vacancies in the YSZ easier than in LZ/YSZ coupled system. The vibrational density of state (VDOS) of scattered phonons explains the trends in thermal conductivity for both systems. In the case of LZ/YSZ coupled-system, LZ keeps more ions vibrated on their original position and reduces the hopping of oxygen ions among vacancies in the YSZ unit, while also providing thermal resistance to ensure lower thermal conductivity of the coupled system.