Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites

Journal of Advanced Ceramics

Yan Xing¹  Xiaojun Zhao²  Yanan Sun³  Fu-Zhi Dai⁴  Yanchun Zhou⁴  Huimin Xiang⁴  Xiaohui Wang⁵ 

[1] New Energy Technology Engineering Laboratory of Jiangsu Province, Nanjing University of Posts and Telecommunications, 210023, Nanjing, China;School of Materials Science and Engineering, Central South University, 410083, Changsha, China;School of Materials Science and Engineering, Central South University, 410083, Changsha, China;Science and Technology on Advanced Functional Composite Laboratory, Aerospace Research Institute of Materials & Processing Technology, 100076, Beijing, China;Science and Technology on Advanced Functional Composite Laboratory, Aerospace Research Institute of Materials & Processing Technology, 100076, Beijing, China;Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang, China;

关键词: high-entropy ceramics;    rare earth oxides;    low thermal conductivity;    thermal expansion coefficient;    CMAS resistance;   

DOI  :  10.1007/s40145-021-0461-6

来源: Springer

【 摘 要 】

Y2O3 is regarded as one of the potential environmental barrier coating (EBC) materials for Al2O3f/Al2O3 ceramic matrix composites owing to its high melting point and close thermal expansion coefficient to Al2O3. However, the relatively high thermal conductivity and unsatisfactory calcium-magnesium-aluminosilicate (CMAS) resistance are the main obstacles for the practical application of Y2O3. In order to reduce the thermal conductivity and increase the CMAS resistance, four cubic bixbyite structured high-entropy oxides RE2O3, including (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3, (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3, (Sm0.2Eu0.2Er0.2Y0.2Yb0.2)2O3, and (Sm0.2Eu0.2Lu0.2Y0.2Yb0.2)2O3 were designed and synthesized, among which (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 bulks were prepared by spark plasma sintering (SPS) to investigate their mechanical and thermal properties as well as CMAS resistance. The mechanical properties of (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 are close to those of Y2O3 but become more brittle than Y2O3. The thermal conductivities of (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 (5.1 and 4.6 W·m−1·K−1) are only 23.8% and 21.5% respectively of that of Y2O3 (21.4 W·m−1·K−1), while their thermal expansion coefficients are close to those of Y2O3 and Al2O3. Most importantly, HE RE2O3 ceramics exhibit good CMAS resistance. After being attacked by CMAS at 1350 °C for 4 h, the HE RE2O3 ceramics maintain their original morphologies without forming pores or cracks, making them promising as EBC materials for Al2O3f/Al2O3 composites.

【 授权许可】

CC BY