A novel approach for the composition design of high-entropy fluorite oxides with low thermal conductivity  

作　　者：Guangjin Chen Cuiwei Li Huaiming Jia Yuwei Zhang Bo Gong Xue Li Tianyu Liu Kepi Chen 

机构地区：[1]School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China [2]School of Energy,Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China

出　　处：《Journal of Advanced Ceramics》2024年第9期1369-1381,共13页先进陶瓷（英文）

基　　金：supported by the Fundamental Research Funds for the Central Universities(Nos.2023YJS062 and 2022JBZY025);the State Key Laboratory of New Ceramic and Fine Processing,Tsinghua University(No.KFZD201902);the Beijing Government Funds for the Constructive Project of Central Universities.

摘　　要：High-entropy fluorite oxides(HEFOs)show significant potential for thermal protection applications due to their advantageous combination of low thermal conductivity and high Yong’s modulus.However,the factors influencing its formation have not been well studied,and a systematic method for compositional design has not yet been established.In this paper,the effects of oxygen vacancy concentration(O_(vac))and mean cation radius(r¯)on formability of HEFOs were investigated to develop a compositional design approach.The results indicate that an appropriate r¯and Ovac is crucial for promoting the formability of single-phase(Ca_(x)Ce_(y1)Zr_(y2)Hf_(z)Sn_(z)Ti_(z))O_(2−δ)HEFOs.High mass/size disorder and an appropriate Ovac(10%)result in(Ca_(0.2)Ce_(0.1)4Zr_(0.1)2Hf_(0.18)Sn_(0.18)Ti_(0.18))O_(2−δ)exhibiting the lowest thermal conductivity of 1.24 W·m^(−1)·K^(−1).Building upon these insights and employing a valence combination strategy,three new single-phase HEFOs with low thermal conductivity were successfully designed and synthesized,namely,(La_(0.28)Y_(0.28)Ce_(0.18)Zr_(0.18)W_(0.08))O_(2−δ),(La_(_(0.3))Y_(_(0.3))Ce_(0.2)Nb_(0.1)Ta_(0.1))O_(2−δ),and(Yb_(0.52)Ce_(0.12)Zr_(0.12)Sn_(0.12)Nb_(0.12))O_(2−δ).This design approach will provide a valuable reference for the design of other high-entropy oxides.

关 键 词：composition design high-entropy fluorite oxides oxygen vacancy phonon scattering thermal conductivity 

分 类 号：TQ174.1[化学工程—陶瓷工业]