Oxidation behavior of Al3BC3 powders at 800–1400 °C in ambient air
Bo Dong, Chengji Deng, Jinghui Di, Jun Ding, Qingyou Zhu, Hao Liu, Hongxi Zhu, Chao Yu
Abstract
The non-isothermal and isothermal oxidation behavior of Al 3 BC 3 powders at 800–1400 °C in the air was studied. The results revealed that the oxidation resistance of Al 3 BC 3 powders was better than that of “Al 8 B 4 C 7 ” powders. At 800–1100 °C, the sintering accelerated the adhesion between the aluminum borate layer and the Al 3 BC 3 core. No micro-crack was observed on both surface and cross-section, thus effectively blocking the diffusion of oxygen and volatilization of reactant gases. The oxidation behavior changed due to the oxidation products growing into a rod shape higher than 1200 °C. The interlocking structure of Al 18 B 4 O 33 micro-rods made the surface of oxidized powder porous. Therefore, the oxygen diffused quickly into Al 3 BC 3 through the porous structure on its surface, leading to rapid oxidation. Jander model could deal with oxidation kinetics and be in good agreement with the experimental data. The calculated apparent activation energy of Al 3 BC 3 powder was equal to 212.76 kJ/mol at 800–1100 °C.