High-entropy perovskite RETa3O9 ceramics for high-temperature environmental/thermal barrier coatings

Four high-entropy perovskite (HEP) RETa3O9 samples were fabricated via a spark plasma sintering (SPS) method, and the corresponding thermophysical properties and underlying mechanisms were investigated for environmental/thermal barrier coating (E/TBC) applications. The prepared samples maintained low thermal conductivity (1.50 W center dot m(-1)center dot K-1), high hardness (10 GPa), and an appropriate Young's modulus (180 GPa), while the fracture toughness increased to 2.5 MPa center dot m(1/2). Nanoindentation results showed the HEP ceramics had excellent mechanical properties and good component homogeneity. We analysed the influence of different parameters (the disorder parameters of the electronegativity, ionic radius, and atomic mass, as well as the tolerance factor) of A-site atoms on the thermal conductivity. Enhanced thermal expansion coefficients, combined with a high melting point and extraordinary phase stability, expanded the applications of the HEP RETa3O9. The results of this study had motivated a follow-up study on tantalate high-entropy ceramics with desirable properties.

Automated summary

Four high-entropy perovskite (HEP) RETa3O9 samples with excellent mechanical properties and thermal properties were fabricated using a spark plasma sintering method. The results showed that the HEP ceramics exhibited low thermal conductivity, high hardness, appropriate Young's modulus, and enhanced fracture toughness. The analysis of different parameters influencing the thermal conductivity can expand the applications of HEP materials.