Oxidation behavior and kinetics of Mg _0.27 Al _2.58 O _3.73 N _0.27 transparent ceramic at high temperatures

Abstract The oxidation behavior, optical properties, and oxidation mechanism of Mg 0.27 Al 2.58 O 3.73 N 0.27 (MgAlON) transparent ceramics in the air at high temperatures were systematically investigated in this work. Above 1000°C, the rapid optical loss of MgAlON transparent ceramics can be attributed to the scattering and refraction of light caused by the generated α ‐Al 2 O 3 second phase, cracks, and pores. Non‐isothermal and isothermal oxidation methods were employed to study the oxidation kinetics of MgAlON transparent ceramics, which obeyed the parabolic law. The oxidation rates at 1300°C, 1400°C, and 1500°C were determined to be 0.048, 1.097, and 7.421 mg 2 /cm 4 ·h, respectively, and the apparent activation energy of oxidation was calculated to be 586.63 kJ/mol. This work revealed the oxidation mechanism of MgAlON transparent ceramics, which guides its practical applications.