Oxidation behavior of Al3BC3 powders at 800–1400 °C in ambient air

Abstract

The non-isothermal and isothermal oxidation behavior of Al3BC3 powders at 800–1400 °C in the air was studied. The results revealed that the oxidation resistance of Al3BC3 powders was better than that of “Al8B4C7” powders. At 800–1100 °C, the sintering accelerated the adhesion between the aluminum borate layer and the Al3BC3 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 Al18B4O33 micro-rods made the surface of oxidized powder porous. Therefore, the oxygen diffused quickly into Al3BC3 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 Al3BC3 powder was equal to 212.76 kJ/mol at 800–1100 °C.

Keywords

• Al3BC3
• Ternary carbides
• Oxidation
• Thermal stability
• Volatilization