The Silicon nitride product is the new material which produces under the specific high temperature high pressure, its essential component is Silicon nitride, it occupies  75% --80% of the total Ingredient,  surplus the  ingredient  of Free iron occupies the  ingredient of total is 12% --17%. The Silicon nitride fine ceramics is a kind of 'hard as diamond, better as steel, lightly as aluminum' the new inorganic nonmetallic material. Silicon nitride has the small pellet, thermostable, toughness, the wearability warm, anti-corrosive, the anti- oxidation, anti- shock, the anti- non-ferrous metal fuses, good self lubricating ability, the electric insulation and so on the fine performance. Silicon nitride is the modern ceramics impels ideal of material the seal.