Oxidation behaviour of nano-sized SiC particulate reinforced Alon composites

Silicon carbide (SiC)–aluminium oxynitride (Alon) ceramic composites exhibited improved mechanical properties, but the high temperature oxidation behaviour was unknown. The aim of this investigation was to identify oxidation characteristics and kinetics of 8 wt% SiC–Alon composites over a temperature range between 700 °C and 1200 °C in air. The Alon matrix and SiC particles near the surface were oxidized to form Al2O3 and SiO2, respectively. The starting oxidation temperature of Alon was observed to be about 1000 °C. While the addition of nano-sized SiC particles resulted in a reduced starting oxidation temperature due to the large cumulative surface area and high total surface energy, the oxidation resistance at higher temperatures of 1100 °C and 1200 °C was remarkably enhanced. The oxidation kinetics changed from a linear weight gain for pure Alon into a logarithmic weight gain for the composites due to the formation of a dense protective oxidation layer arising from the presence of SiO2.