High-entropy ferroelastic(10RE_(0.1))TaO_(4) ceramics with oxygen vacancies and improved thermophysical properties  

作　　者：Jun Wang Xiaoyu Chong Liang Lv Yuncheng Wang Xiaolan Ji Haitao Yun Jing Feng 

机构地区：[1]Faculty of Material Science and Engineering,Kunming University of Science and Technology,Kunming 650093,China [2]AECC South Industry Co.,Ltd.,Zhuzhou 412000,China

出　　处：《Journal of Materials Science & Technology》2023年第26期98-106,共9页材料科学技术（英文版）

基　　金：financially supported by the Rare and Precious Metals Material Genetic Engineering Project of Yunnan Province(Nos.202102AB080019-1 and 202002AB080001-1);the Yun-nan Fundamental Research Projects(Nos.202101AW070011 and 202101BE070001-015).

摘　　要：The primary purpose of this work is to optimize the thermophysical properties of rare-earth tan-talate ceramics using the high-entropy effect.Here,the high-entropy rare-earth tantalate ceramic(Y_(0.1)Nd_(0.1)Sm_(0.1)Gd_(0.1)Dy_(0.1)Ho_(0.1)Er_(0.1)Tm_(0.1)Yb_(0.1)Lu_(0.1))TaO_(4)((10RE_(0.1))TaO_(4))is synthesized successfully.The lat-tice distortion and oxygen vacancy concentration are characterized firstly in the rare-earth tantalates.Notably,compared with single rare-earth tantalates,the thermal conductivity of(10RE_(0.1))TaO_(4) is reduced by 16%-45%at 100℃ and 22%-45%at 800℃,and it also presents lower phonon thermal conductivity in the entire temperature range from 100 to 1200℃.The phonon thermal conductivity(1.0-2.2 W m^(-1) K^(-1),100-1200℃)of(10RE_(0.1))TaO_(4) is lower than that of the currently reported high-entropy four-,five-and six-component rare-earth tantalates.This is the result of scattering by the ferroelastic domain,lattice distortion associated with size and mass disorder,and point defects,which target low-,mid-and high-frequency phonons.Furthermore,(10RE_(0.1))TaO_(4),as an improved candidate for thermal barrier coatings materials(TBCs),has a higher thermal expansion coefficient(10.5×10^(-6)K^(-1) at 1400℃),lower Young’s modulus(123 GPa)and better high-temperature phase stability than that of single rare-earth tantalates.

关 键 词：High-entropy rare-earth tantalate ceramic Ferroelastic domain Lattice distortion Oxygen vacancy Thermal conductivity Thermal barrier coatings materials 

分 类 号：TG139[一般工业技术—材料科学与工程]