Silicon nitride is an important structural ceramic material. It is a superhard substance, inherently lubricious, and wear-resistant, and is an atomic crystal; it resists oxidation at high temperatures. Moreover, it can also resist cold and heat shocks, and it will not shatter when heated to above 1000°C in the air, cooled rapidly and heated again sharply. Silicon nitride ceramics have high fracture toughness, compressive strength close to corundum, self-lubricating and anti-wear. High temperature resistance, low coefficient of thermal expansion, and excellent thermal conductivity. Use it to make bearings, gas turbine blades, mechanical seal rings, permanent molds and other mechanical components.

Silicon nitride ceramics is a kind of high-temperature resistant and high-strength structural ceramics with broad prospects. It occupies an important position in high-tech ceramics. It has high performance (such as high strength, high hardness, good thermal shock resistance, high fatigue toughness, High bending strength at room temperature, wear resistance and chemical corrosion resistance and good high temperature stability, oxidation resistance, etc.), compared with other ceramics, silicon nitride ceramics have a small specific gravity, low thermal expansion coefficient, good thermal shock resistance, fracture toughness High, is an ideal high-temperature structural materials and ceramic materials for high-speed cutting tools. Therefore, silicon nitride ceramics have a wide range of uses in aerospace, automobile engine, machinery, chemical industry, petroleum and other fields, and have also created a new situation for the development of new high-temperature structural materials. At present, the main problems of silicon nitride products are low toughness and high cost. In the future, the powder making, molding, and sintering processes and the compounding of silicon nitride and silicon carbide should be improved to develop silicon nitride ceramics with better performance.

The initial application of silicon nitride ceramics is mainly used in machinery, metallurgy, chemical industry, aviation, semiconductor and other industries, as parts of some equipment or products, and achieved good expected results. In recent years, with the development of manufacturing industry and testing and analysis technology, the reliability of silicon nitride ceramic products has been continuously improved, so the application area has been continuously expanded.