Design and experimental investigation of potential low-thermalconductivity high-entropy rare-earth zirconates  

作　　者：Lu Liu Hongying Dong Peng Zhang Shaokun Wang Haolei Qil Mengyu Ding Zhefeng Li Yu Bai Wen Ma 

机构地区：[1]School of Chemical Engineering,Inner Mongolia University of Technology,Hohhot 010051,China [2]Inner Mongolia Key Laboratory of Thin Film and Coatings,School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China

出　　处：《Journal of Advanced Ceramics》2024年第8期1132-1142,共11页先进陶瓷（英文）

基　　金：This work is supported by the National Natural Science Foundation of China(Nos.51865044,52062040);Science and Technology Projects of Inner Mongolia Autonomous Region(Nos.2021PT0008,2022ZD02,2022MS05003);Basic Scientific Research Expenses Program of Universities Directly under Inner Mongolia Autonomous Region(Nos.JY20220041,JY20220062).

摘　　要：Developing new high-entropy rare-earth zirconate(HE-RE_(2)Zr_(2)O_(7))ceramics with low thermal conductivity is essential for thermal barrier coating materials.In this work,the average atomic spacings,interatomic forces,and average atomic masses of 16 rare-earth elements occupying the A site of the cubic A_(2)B_(2)O_(7) crystal structure were calculated by density functional theory.These three physical qualities,as vectors,characterize the corresponding rare-earth elements.The distance between two vectors quantitatively describes the difference between two rare-earth elements.For greater differences between two rare-earth elements,the disorder degree of HE-RE_(2)Zr_(2)O_(7)is greater,and therefore,the thermal conductivity is lower.According to the theoretical calculations,the thermal conductivity of the ceramics gradually increases in the order of(SC_(0.2)Y_(0.2)La_(0.2)Ho_(0.2)Yb_(0.2))_(2)Zr_(2)0_(7),(SC_(0.2)Ce_(0.2)Nd_(0.2)Eu_(0.2)Gd_(0.2))_(2)Zr_(2)0_(7),(SC_(0.2)Y_(0.2)Tm_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)0_(7),and(Sc_(0.2)Er_(0.2)Tm_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7).Using the solution precursor plasma spray method and pressureless sintering method,four types of HE-RE2Zr2Oz powder and bulk samples were prepared.The samples all showed a single defective fluorite structure with a uniform distribution of the elements and a stable phase structure.The thermal conductivities of the sintered HE-RE_(2)Zr_(2)0_(7) bulk samples ranged from 1.30 to 1.45 Wm^(-1).K^(-1) at 1400℃,and their differences were consistent with the theoretical calculation results.Among the ceramics,(Sc_(0.2)Y_(0.2)La_(0.2)Ho_(0.2)Yb_(0.2))_(2)Zr_(2)O_(7) had the lowest thermal conductivity(1.30 W·m^(-1)·K^(-1),1400℃),highest thermal expansion coefficient(10.19×10^(-6) K^(-1),200-1400℃),highest fracture toughness(1.69±0.28 MPa·m^(1/2)),and smallest brttleness index(3.03μm^(1/2)).Therefore,(Sc_(0.2)Y_(0.2)La_(0.2)Ho_(0.2)Yb_(0.2))_(2)Zr_(2)0_(7)is considered to be an ideal candidate material for next-generation thermal barrier coat

关 键 词：high-entropy ceramics rare-earth zirconate(HE-RE_(2)Zr_(2)O_(7)) composition design thermal conductivity thermal barriercoatings(TBCs) 

分 类 号：TB383.3[一般工业技术—材料科学与工程]