Abstract This paper aims to provide an insight into thermophysical properties of series tetragonal Sc2O3-Y2O3 co-stabilized ZrO2 (ScYSZ) materials. Phonon density of states and point-defect scattering model were employed to explain the variation of thermal conductivity of ScYSZ materials. The results suggested that the smaller interionic distance of Sc3+–O2− than Y3+–O2− provided larger atomic attraction, which created an effective migration barrier to ensure the better structural stability of ScYSZ. Compared with Y2O3 stabilized ZrO2 (YSZ), ScYSZ had lower phonon group velocity and thermal conductivity, which gradually decreased with the increase of Sc3+ content. Thermal expansion coefficient of ScYSZ was comparable to that of YSZ due to the combined effect of temperature, structural density, lattice defect and chemical composition. The substitution of Sc3+ for Y3+ played a minor role in the change of thermal expansion coefficient of YSZ. ScYSZ with good thermophysical properties is a prospective candidate material for high-temperature TBCs application.

中文翻译：

---

Sc 取代对四方 ScYSZ 热物理性质的影响：分子动力学模拟

摘要 本文旨在深入了解系列四方 Sc2O3-Y2O3 共稳定 ZrO2 (ScYSZ) 材料的热物理性质。声子态密度和点缺陷散射模型被用来解释ScYSZ材料热导率的变化。结果表明，Sc3+–O2− 的离子间距比 Y3+–O2− 更小，提供了更大的原子吸引力，从而形成了有效的迁移屏障，以确保 ScYSZ 更好的结构稳定性。与Y2O3稳定的ZrO2（YSZ）相比，ScYSZ具有较低的声子群速度和热导率，随着Sc3+含量的增加而逐渐降低。由于温度、结构密度、晶格缺陷和化学成分的综合影响，ScYSZ 的热膨胀系数与 YSZ 相当。Sc3+对Y3+的替代对YSZ热膨胀系数的变化影响较小。ScYSZ 具有良好的热物理性能，是高温 TBC 应用的潜在候选材料。