Corrosion of aluminum oxynitride based ceramics by molten steel

Aluminum oxynitride (AlON) exhibits excellent stability, chemical and mechanical properties. Corrosion resistance to molten steel is an important performance index of ceramic refractories. While silicon carbide (SiC) particles have been proven to improve the mechanical properties and thermal shock resistance of AlON ceramic, the corrosion of AlON and SiC–AlON composites by molten steel were unknown. The aim of this investigation was to evaluate the corrosion resistance to molten steel and identify the underlying mechanisms of AlON ceramic and 8 wt% SiC–AlON composites at the temperature of 1550 °C for 30 min. Due to the reaction between AlON and molten steel, a solid product of Al2O3 is detected in the corrosion region. Besides, some round shaped pores form and increase toward the sample surface in the corrosion region. The thickness of corrosion region of AlON ceramic is about 150 μm, indicating that the AlON ceramic has an excellent corrosion resistance to molten steel. However, the corrosion resistance of 8 wt% SiC–AlON composites to molten steel can be characterized with a penetrated depth of approximately 250 μm. This is mainly attributed to the thermal dissociation of SiC and the reaction between SiC and molten steel.