Solvothermal-derived multicomponent rare-earth cerate ceramics toward remarkable thermophysical properties

The multicomponent rare-earth cerate (Y 0.2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2 Ce 2 O 7 (5RE 2 Ce 2 O 7 ) ceramics were successfully fabricated through solvothermal method and the following calcination process. The microstructure and phase composition of the as-obtained products were systematically characterized via SEM, TEM and XRD techniques. The results showed that the as-synthesised 5RE 2 Ce 2 O 7 has a single-phase fluorite-type crystal structure with the particle size of approximately 200 nm. Furthermore, the as-synthesised 5RE 2 Ce 2 O 7 demonstrated lower thermal conductivity (1.9–1.26 W m −1 ·K −1 at 25–1000 °C), higher thermal expansion coefficients (CTEs, 12.48 × 10 −6  K −1  at 1000 °C), and outstanding mechanical properties including large Young's modulus (248.0 ± 0.35 GPa) and high fracture toughness (2.4 ± 0.21 MPam 1/2 ). The excellent properties of the as-synthesised 5RE 2 Ce 2 O 7 demonstrates its potential application as a new type of next-generation TBCs .