Effect of Yb³⁺–Ce⁴⁺ content on mechanical, thermophysical, and CMAS resistance properties of La₂−xYbxZr₂−xCexO₇ ceramics

Mechanical, thermophysical, and CMAS resistance properties of La 2− x Yb x Zr 2− x Ce x O 7 ( x = 0.00, 0.25, 0.50, 0.75, 1.00) ceramics were studied. La 2− x Yb x Zr 2− x Ce x O 7 ( x ≠ 0.0) has higher Vickers hardness ( H V ) and fracture toughness ( K IC ) than La 2 Zr 2 O 7 . When the Yb 3+ –Ce 4+ concentration of La 2− x Yb x Zr 2− x Ce x O 7 grows, its thermal conductivity drops, thermal expansion coefficient increases, and CMAS corrosion resistance improves. LaYbZrCeO 7 has the smallest thermal conductivity (1200°C, 1.285 W/(m K)), the largest thermal expansion coefficient (1200°C, 10.554 × 10 −6 /K), and the best CMAS corrosion resistance (1300°C, 30 min, the reaction layer thickness is merely ∼5.1 µm). Its H V and K IC values were 10.10 GPa and 2.14 MPa m 1/2 , respectively, much higher than those of La 2 Zr 2 O 7 (8.20 GPa, 1.77 MPa m 1/2 ). Thus, LaYbZrCeO 7 shows good comprehensive performance.