Kinetic studies of oxidation of MgAlON and a comparison of the oxidation behaviour of AlON, MgAlON, O'SiAlON-ZrO2, and BN–ZCM ceramics

Abstract

Abstract The kinetics and morphology of the oxidation process of magnesium-aluminium oxynitride (MgAlON), aluminium oxynitride (AlON), O'SiAlON–ZrO2, and BN-ZCM have been studied in the temperature range 1373–1773 K. Oxidation experiments with powder and plate samples of the above materials have been carried out in air. MgAlON shows the best resistance to oxidation at lower temperatures (<1473 K), whereas at higher temperatures (∼773 K), AlON shows the best resistance. O'SiAlON–ZrO2 shows very good oxidation resistance up to 1673 K. But its oxidation rate increases strongly above 1673 K, presumably due to the formation of liquid phase. BN–ZCM has the poorest oxidation resistance due to the evaporation of B2O3. The activation energies for the chemical oxidation reaction of AlON, MgAlON, and O'SiAlON–ZrO2 are 214, 330 and 260 kJ/mol, respectively. The overall diffusion activation energies for AlON, MgAlON, O'SiAlON–ZrO2 and BN–ZCM are 227, 573, 367 and 289 kJ/mol, respectively.