Enhanced high-temperature performance of selected high-entropy rare earth disilicates

First-principles calculations were utilized to evaluate the synthesis feasibility of (Yb0.2Y0.2Lu0.2Ho0.2Er0.2)(2)Si2O7, (Yb0.2Tm0.2Lu0.2Sc0.2Er0.2)(2)Si2O7, (Yb0.2Tm0.2Lu0.2Sc0.2Gd0.2)(2)Si2O7, and (Yb0.2Y0.2Lu0.2Sc0.2Gd0.2)(2)Si2O7, followed by their fabrication using the solid-phase reaction method. This study investigates the thermal properties of four novel high-entropy rare earth disilicates and compares them with Yb2Si2O7, a material known for its high-temperature stability. The aim was to explore the influence of high configurational entropy and small grain size on enhancing material properties that are critical in high-temperature applications. Key findings demonstrated that these high-entropy materials exhibit lower thermal conductivity, higher specific heat capacity, an0d reduced coefficient of thermal expansion compared to Yb2Si2O7. Among them, (Yb0.2Tm0.2Lu0.2Sc0.2Er0.2)(2)Si2O7 and (Yb0.2Y0.2Lu0.2Ho0.2Er0.2)(2)Si2O7 have the lowest thermal conductivity and suitable CTE, making them the best choices for advanced thermal/environmental barrier coatings in high-temperature applications. Furthermore, the in-depth discussion in this study provides guidance for designing high-entropy rare earth disilicate materials with ideal CTE and thermal insulation properties.