High-temperature oxidation behaviors of dense TMC (TM= Ta, Nb, Ti and Zr) ceramics in air
This study investigated the high-temperature oxidation behaviors of TMC ceramics. The results indicate that the high-temperature oxidation curves of the four TMC ceramics follow a parabolic law, suggesting a diffusion-controlled process. The activation energies for the oxidation of TaC, NbC, TiC, and ZrC ceramics are 105.4, 124.3, 169.3, and 78.7 kJ/mol, respectively, with oxidation rate constants at 1000 °C of 16.84, 40.45, 0.18, and 14.43 mg 2 /cm 4 ·h for each ceramic, respectively. The temperatures at which the ceramics disintegrate into fragments in high-temperature air are 800, 800, >1000, and 600 °C, respectively. The anti-oxidation performance of the four TMC ceramics ranks as follows: TiC > TaC > NbC > ZrC. In comparison to the reported high-entropy carbide ceramics, the TiC ceramic in this study demonstrates superior anti-oxidation performance due to dense TiO 2 layer formation, characterized by significantly low oxidation rates and excellent structural stability.
危险品化学品经营许可证(带存储)