ABO3钙钛矿氧化物结构稳定性与力/热学性能的第一性原理计算研究

First-Principles Calculations of Structural Stability and Mechanical/Thermal Properties of ABO3 Perovskites

摘要:

热障涂层是一种用于航空发动机等极端环境的热防护功能涂层，其可保证装备的热力学性能及结构的稳定，对于高速飞行器安全可靠的服役具有战略性的意义。随着航空发动机服役温度逐代提升，现役Y₂O₃稳定的ZrO₂热障涂层已不能满足需求而无法继续安全服役，急需开发新型涂层材料。ABO₃（A=Ca、Sr、Ba，B=Ti、Zr、Hf、Sn、Ce）钙钛矿型氧化物因优异的物理化学性能，以及宽泛的成分空间和丰富的构型空间，近年来受到了广泛的关注。目前，对于ABO₃类材料的研究多聚焦于单一晶相钙钛矿氧化物的性能表征方面，而不同晶相间的力学/热学性能、构效关系的对照研究及内在关联机制尚未系统阐明。因此，围绕系列钙钛矿型氧化物ABO₃展开了第一性原理研究，对其中的正交相及立方相钙钛矿氧化物进行了力学/热学性能预测，综合考虑其不同晶相间的性能差异，建立材料成分与力/热性能之间的影响关系。结果表明，当B位元素为Ce时，由于其原子半径较大而造成化学键各向异性显著，使得铈酸盐在获得最低热导率的同时力学性能明显弱化，与之相比，锆酸盐和铪酸盐兼具较高的力学性能及较低的热导率。基于此调控规律，采用适当的掺杂和固溶体设计，进一步进行微观结构形态的调控，有望获得高温行为更稳定的新型钙钛矿基高温材料。该研究为多晶相钙钛矿材料的性能平衡设计提供了理论指导，对于进一步优化和设计具有优良性能的新型钙钛矿氧化物陶瓷具有重要意义。

Abstract:

Thermal barrier coating is a thermal protection functional coating used in extreme environments such as aircraft engines， which has significance for the safe and reliable operation of high-speed aircraft. With the increase in service temperature of next generation engines， the current Y₂O₃-stabilized ZrO₂ cannot meet the demand， and thus new materials are needed. ABO₃ perovskite oxides， possessing designable properties for their various cation options and structural diversity， have received considerable attention. Currently， existing research has mainly focused on the performance characterization of specific phases of perovskite oxides， while comparative studies between different crystal phases and their structure-property relationships have rarely been systematically elucidated. In this work， first-principles calculations were conducted on a series of perovskite-type oxides ABO₃（A=Ca， Sr， Ba； B=Ti， Zr， Hf， Sn， Ce）. The mechanical/thermal properties of orthorhombic-phase and cubic-phase perovskites were predicted. The relationship between material composition and mechanical/thermal properties was developed based on phase comparisons. When Ce occupied the B-site， its large atomic radius caused significant chemical bond anisotropy， resulting in low thermal conductivity but compromised mechanical properties. In comparison， zirconates and hafnates demonstrated balanced performance with superior mechanical properties and relatively low thermal conductivity. These findings provided critical insights into the performance balance of multiphase perovskites. Appropriate doping and solid solution design may be adopted to further optimize the high-temperature properties of perovskite-based thermal barrier material. Moreover， the methods and results used in this work are of great significance for further optimization and design of novel perovskite oxide ceramics with excellent performance.