Studies on nitrogenization reaction in liquid-phase sintering of SiC ceramic

SiC ceramic was sintered through liquid phase by using SiO2 as the sintering additive. Mixed N-2 and CO gas was used as the sintering atmosphere. The microstructure of the densified SiC ceramic was observed by using transmission electron microscopy (TEM), Bar-like ting crystal was found to distribute in the intergranular phase. The crystal was identified by spatially-resolved electron energy-loss spectroscopy (EELS) to be Si2N2O. It is suggested that nitrogen, coming from the sintering atmosphere, attends the chemical reaction in SiC ceramic at sintering temperature and is responsible for the appearance of the Si2N2O crystalline.