Silicon nitride is an inorganic substance with chemical formula Si3N4. It is an important structural ceramic material, hardness, itself has lubricity, and wear resistance, for atomic crystal; Oxidation resistance at high temperature. And it can resist hot and cold shock, heating in the air to more than 1000 degrees Celsius, sharp cooling and sharp heating, will not shatter. Because of its excellent properties, SI3N4 ceramics are often used to manufacture bearings, turbine blades, mechanical sealing rings, permanent molds and other mechanical components. If the heating surface of engine parts is manufactured with silicon nitride ceramics which are resistant to high temperature and not easy to heat transfer, the quality of diesel engine can be improved, fuel saving and thermal efficiency can be improved.

Silicon nitride is used as advanced refractory materials, such as Si3N4-SIC refractory materials combined with SIC for blast furnace body and other parts; If combined with BN as Si3N4-BN material, used for horizontal continuous casting separation ring. Si3n4-bn series horizontal continuous casting separation ring is a kind of fine structure ceramic material with uniform structure and high mechanical strength. Good heat shock resistance, and will not be wet by liquid steel, in line with the process requirements of continuous casting.