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 ℃, which is attributed to LYZCO's higher TEC (10.431×10 −6 /K, 1100 ℃) and lower thermal conductivity (1.299 W/(m·K), 1100 ℃). 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.
A new type of SiCf/TiC-Ti3SiC2composite was prepared by the Spark Plasma Sintering (SPS) method in this work. The phase transformation and interface cracking of this composite under ion irradiation (single Xe, Xe + He, and Xe + He + H ions) and subsequent annealing were analyzed using transmission electron microscopy (TEM), mainly focusing on the interface regions. Xe ion irradiation resulted in the formation of high-density stacking faults in the TiC coatings and the complete amorphization of SiC fibers. The implanted H ions exacerbated interface coarsening. After annealing at 900 °C for 2 h, the interface in the Xe + He + H ion-irradiated samples was seriously damaged, resulting in the formation of large bubbles and cracks. This damage occurred because the H atoms reduced the surface free energy, thereby promoting the nucleation and growth of bubbles. Due to the absorption effect of the SiCf/TiC interface on defects, the SiC fiber areas near the interface recovered back to the initial nano-polycrystalline structure after annealing.
危险品化学品经营许可证（带存储）