High-entropy(Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3: A promising thermal/environmental barrier material for oxide/oxide composites

• 作者: Fu-Zhi Dai Heng Chen Huimin Xiang Kuang Sun Wei Xu Xiaohui Wang Yanchun Zhou Zhijian Peng Zifan Zhao
• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2020,（12）
• 页码范围: 45-51
• 页数: 7页
• 语种: 英文

摘要

Yttrium aluminum perovskite (YAlO3) is a promising candidate material for environmental barrier coatings (EBCs) to protect Al2O3f/Al2O3 ceramic matrix composites (CMCs) from the corrosion of high-temperature water vapor in combustion environments.Nevertheless,the relatively high thermal conductivity is a notable drawback of YAlO3 for environmental barrier coating application.Herein,in order to make REAlO3 more thermal insulating,a novel high-entropy rare-earth aluminate ceramic (Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3 was designed and synthesized,The as-prepared (Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3 ceramic possesses close thermal expansion coefficient (9.02× 10-6 /℃ measured from room temperature to 1200℃) to that of Al2O3.The thermal conductivity of (Y0.2Nd0.2Sm0.2Eu0.2Er0.2) AlO3 at room temperature is 4.1 W·m-1 K-1,which is almost one third of the value of YAlO3.Furthermore,to effectively prevent the penetration of water vapor from possible pores/cracks of coating layer,which are often observed in T/EBCs,a tri-layer EBC system REAlO3/RE3AlsO12/(Al2O3f/Al2O3 CMCs) is designed.Close thermal expansion coefficient to A12O3 and low thermal conductivity of (Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3,as well as the formation of dense garnet layer at (Y0.2Nd0.2Sm0.2Eu0.2Er0.2)AlO3/Al2O3 interface,indicate that this new type of high-entropy ceramic is suitable as a candidate environmental barrier coating material for Al2O3f/Al2O3 CMCs.