Oxidation of β-SiAlONs prepared by a combination of combustion synthesis and spark plasma sintering

The oxidation of β-Si6−zAlzOzN8−zs (z = 1, 2, and 3) prepared by a combination of combustion synthesis (CS) and spark plasma sintering (SPS) was investigated. The oxidation experiments were conducted at temperatures of 1000, 1200, and 1400 °C in air for 100 h (360 ks). Their oxidation kinetics follow a parabolic rate law, and the deviation from that increases with a decrease in the z value. The results of XRD and EPMA show that the oxide formed on β-SiAlONs (z = 1 and 2) consists of silica and mullite, and on β-SiAlON (z = 3) of only mullite.