RT Journal Article A1 Zeyu Chen,Chucheng Lin,Wei Zheng,Xuemei Song,Caifen Jiang,Yaran Niu,Yi Zeng; AD 材料科学与光电子工程中心, 中国 ; 高性能陶瓷和超微结构国家重点实验室, 中国 ; 高性能陶瓷和超微结构国家重点实验室, 中国 ; 高性能陶瓷和超微结构国家重点实验室, 中国 ; 材料科学与光电子工程中心, 中国 ; 高性能陶瓷和超微结构国家重点实验室, 中国 ; 高性能陶瓷和超微结构国家重点实验室, 中国 ; 中国科学院无机涂层材料重点实验室, 中国 ; 高性能陶瓷和超微结构国家重点实验室, 中国 T1 Influence of average radii of RE3+ ions on phase structures and thermal expansion coefficients of high-entropy pyrosilicates YR 2023 IS 5 vo 12 OP 1090-OP 1104 K1 phase structure;environmental barrier coatings (EBCs);high-entropy pyrosilicates;thermal expansion coefficient (CTE) AB High-entropy pyrosilicate element selection is relatively blind, and the thermal expansion coefficient (CTE) of traditional β-type pyrosilicate is not adjustable, making it difficult to meet the requirements of various types of ceramic matrix composites (CMCs). The following study aimed to develop a universal rule for high-entropy pyrosilicate element selection and to achieve directional control of the thermal expansion coefficient of high-entropy pyrosilicate. The current study investigates a high-entropy design method for obtaining pyrosilicates with stable β-phase and γ-phase by introducing various rare-earth (RE) cations. The solid-phase method was used to create 12 different types of high-entropy pyrosilicates with 4–6 components. The high-entropy pyrosilicates gradually transformed from β-phase to γ-phase with an increase in the average radius of RE3+ ions ( r¯(RE3+)). The nine pyrosilicates with a small r¯(RE3+) preserve β-phase or γ-phase stability at room temperature to the maximum of 1400 ℃. The intrinsic relationship between the thermal expansion coefficient, phase structure, and RE–O bond length has also been found. This study provides the theoretical background for designing high-entropy pyrosilicates from the perspective of r¯(RE3+). The theoretical guidance makes it easier to synthesize high-entropy pyrosilicates with stable β-phase or γ-phase for the use in environmental barrier coatings (EBCs). The thermal expansion coefficient of γ-type high-entropy pyrosilicate can be altered through component design to match various types of CMCs. SN 2226-4108 LA EN