Liew Siao Li, Rafiq Nafisah Bte Mohd, Ni Xi Ping, Sng Anqi, Lim Poh Chong, Zhou Jun, Wang Shijie
Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore 138634, Republic of Singapore.
Inorg Chem. 2025 Feb 3;64(4):1726-1733. doi: 10.1021/acs.inorgchem.4c03942. Epub 2025 Jan 19.
High-entropy ceramics hold promise for application as thermal barrier coating materials. However, a key challenge in practical applications lies in the low fracture toughness compared to that of yttria-stabilized zirconia (YSZ). Herein, we designed (Hf,Zr,Ce,)O-AlO (M = Y, Ca, and Gd) ceramic composites by following a set of fundamental guidelines. First-principles calculations predicted that the inclusion of AlO in compositions containing the other four binary oxides decreased the propensity for single high-entropy phase formation. Instead, it increased the potential for AlO to form a second phase within the high-entropy ceramic matrix, compared to compositions without AlO. Ceramic composites consisting of the AlO second phase in a high-entropy fluorite oxide (Hf,Zr,Ce,)O matrix were synthesized in situ via conventional solid-state reactions from the five constituent binary oxides. Both the hardness and fracture toughness of the ceramic composites were enhanced due to toughening mechanisms from the discrete AlO particles, microcracks, and crack deflections. Additionally, the ceramic composites exhibited coefficients of thermal expansion and thermal conductivities comparable with those of YSZ. Our findings demonstrated the potential of the high-entropy (Hf,Zr,Ce,)O-AlO ceramic composites for advanced thermal barrier coating materials and offered a possible approach to reinforce other high-entropy oxide-based ceramic systems.
高熵陶瓷有望用作热障涂层材料。然而，实际应用中的一个关键挑战在于与氧化钇稳定的氧化锆（YSZ）相比，其断裂韧性较低。在此，我们遵循一系列基本准则设计了（Hf,Zr,Ce）O-AlO（M = Y、Ca和Gd）陶瓷复合材料。第一性原理计算预测，在含有其他四种二元氧化物的成分中加入AlO会降低形成单一高熵相的倾向。相反，与不含AlO的成分相比，它增加了AlO在高熵陶瓷基体中形成第二相的可能性。通过传统的固态反应，由五种二元氧化物原位合成了在高熵萤石氧化物（Hf,Zr,Ce）O基体中含有AlO第二相的陶瓷复合材料。由于离散的AlO颗粒、微裂纹和裂纹偏转等增韧机制，陶瓷复合材料的硬度和断裂韧性均得到了提高。此外，陶瓷复合材料的热膨胀系数和热导率与YSZ相当。我们的研究结果证明了高熵（Hf,Zr,Ce）O-AlO陶瓷复合材料作为先进热障涂层材料的潜力，并为增强其他高熵氧化物基陶瓷体系提供了一种可能的方法。
