Thermal cycling behavior of Yb3+-Ce4+co-doped La2Zr2O7-based TBCs: Experimental and theoretical research

The thermal cycling behavior of Yb 3+ -Ce 4+ -La 2 Zr 2 O 7 /YSZ (LYZCO/YSZ) TBCs was systematically investigated via experiment and first -principles calculation. Results suggest that ceramic grain boundary cracking is the root cause of LYZCO/YSZ TBCs thermal cycle failure. Compared to La 2 Zr 2 O 7 /YSZ TBCs, LYZCO/YSZ TBCs own an outstanding thermal cycle life at 1100 degrees C, which is attributed to LYZCO's higher TEC (10.431x10 -6 /K, 1100 degrees C) and lower thermal conductivity (1.299 W/(m center dot K), 1100 degrees C). Furthermore, Griffith's separation work of the LYZCO/YSZ interface is merely -0.576 J/m 2 , implying that the LYZCO/YSZ TBCs are particularly prone to cracking at this interface. Weakly bonded La -O is the first site at this interface cracking.