Corrosion of engineering ceramic materials by molten iron part I: Silicon nitride and SiAlON

The corrosion resistance of two different polycrystalline materials (Si3N4, SiAlON) by molten iron at 1600 °C has been investigated. Silicon nitride reacts with molten iron very rapidly while SiAlON exhibited the improved corrosion resistance. Better corrosion resistance of SiAlON is caused by the formation of protective layer of Al2O3 in the initial stage of corrosion test. In the present work the influence of exposure time on the residual strength of the polycrystalline materials has also been estimated. The strength of the SiAlON after 8 h of corrosion was only 20% of the initial strength of the same material before corrosion.