Thermal Conductivity and Expansion Coefficient of (Sm1−xYbx)2Ce2O7 Ceramics for Thermal Barrier Coatings

In the current paper, the (Sm1−xYbx)2Ce2O7 ceramics were prepared via sol–gel and high-temperature solid reaction methods. The phase composition, microstructure, thermal conductivity, and expansion coefficient were investigated. Results indicate that pure (Sm1−xYbx)2Ce2O7 ceramics with single defect-fluorite structure are synthesized successfully. Owing to the phonon scattering caused by Yb addition, the thermal conductivity of (Sm1−xYbx)2Ce2O7 ceramics decreases with increasing Yb2O3 content at identical temperatures, which is lower than that of YSZ. Due to the relatively low ionic radius of Yb3+ ions, the addition of Yb2O3 decreases the thermal expansion coefficient of (Sm1−xYbx)2Ce2O7 ceramics, which is higher than that of 8YSZ. The synthesized (Sm1−xYbx)2Ce2O7 ceramics can be explored as candidate materials for thermal barrier coatings.