Abstract: Clay bonded SiC ceramic materials were prepared with clay and SiC fine powder as main raw materials. The effects of sintering atmosphere (air, buried carbon and nitrogen) on its phase composition, microstructure, bulk density, apparent porosity, compressive strength and other properties were studied. The results show that the main components of the samples burned in three kinds of atmosphere are SiC and glass phase, but a small amount of cristobalite and silicon oxynitride are formed in the samples burned in air and nitrogen atmosphere respectively；The high partial pressure of O2 and CO will have an adverse effect on the material. Large area "bubbling" phenomenon appears on the surface of the sample sintered in air atmosphere, and the uniformity of the macro and micro structure of the material is not good; The sintering property and strength of the samples sintered in carbon atmosphere are the worst and the lowest; The samples sintered in nitrogen atmosphere have uniform structure, the highest strength and the best comprehensive properties.

Key words: Clay bonded SiC, Sintering atmosphere, Properties