Improvement of high-temperature oxidation resistance of Y-α-SiAlON with high nitrogen content by lowering Y/Si ratio

Oxidation behavior of highly transparent Y-α-SiAlON ceramics with high nitrogen content (n = 1.0) and lowered Y/Si ratio (0.041) at 1200-1400 °C within 32 h was investigated by measuring its phase assemblage, elemental composition and weight gain during oxidation process. Comparing to the reported Y-α-SiAlON, the obtained one has a lower oxidation rate at 1200 °C and 1300 °C. Oxidation rate at 1400 °C before 16 h is equivalent to the reported rate at 1300 °C. Improvement of oxidation resistance of the obtained Y-α-SiAlON characterized by single-crystalline phase and high density is attributed to its high nitrogen content and lowered Y/Si ratio.