Thermophysical performances of (La1/6Nd1/6Yb1/6Y1/6Sm1/6Lu1/6)2Ce2O7 high-entropy ceramics for thermal barrier coating applications

In this study, a novel high-entropy oxide of (La1/6Nd1/6Yb1/6Y1/6Sm1/6Lu1/6)(2)Ce2O7 was prepared using a sol-gel and high-temperature sintering technology. Additionally, its lattice structure, micro-morphology, elemental composition, and thermophysical and mechanical properties were evaluated. The results revealed that the obtained oxide powder has a typical fluorite-type lattice with particle sizes in the range of similar to 30-100 nm. The bulk sample has a dense microstructure and uniform elemental distribution. Owing to its low lattice order, the thermal expansion coefficient of (La1/6Nd1/6Yb1/6Y1/6Sm1/6Lu1/6)(2)Ce2O7 is greater than that of Sm2Ce2O7, which also exhibits excellent lattice stability up to 1200 degrees C. Further, owing to phonon scattering due to lattice distortion, oxygen vacancy, and cation substitution, the thermal conductivity of (La1/6Nd1/6Yb1/6Y1/6Sm1/6Lu1/6)(2)Ce2O7 is lower than that of Sm2Ce2O7, while its mechanical performance is inferior to that of 7YSZ.

Automated summary

A novel high-entropy oxide of (La1/6Nd1/6Yb1/6Y1/6Sm1/6Lu1/6)(2)Ce2O7 was prepared with a typical fluorite-type lattice structure and particle sizes in the range of 30-100 nm; due to its low lattice order, it exhibits a higher thermal expansion coefficient and excellent lattice stability at high temperature; influenced by lattice distortion, it has a lower thermal conductivity compared to other oxides.