Thermodynamic calculation, preparation and properties of Y2(Zr1/6Ti1/3Ge1/6Hf1/12Sn1/4)2O7 high-entropy pyrochlore ceramics.

Many factors impact the formability of single phase high-entropy pyrochlore ceramics (HEPCs) which become a research hotspot owing to their excellent properties. To investigate the effect of size disorder, two combinations with same mixing entropy and different size disorder were designed, thermodynamic analysis of first-principles calculations and experimental research were conducted in this paper. The calculation results reveal that the enthalpy change decreases significantly with the decrease of size disorder, promoting the synthesis of single-phase high-entropy pyrochlore. The experimental results prove that the combination with lower size disorder leads to single-phase HEPCs, and the prepared material exhibits low thermal conductivity (1.68 W/(m·K)) and low theoretical density (5.73 g/cm3). [ABSTRACT FROM AUTHOR]