Silicon nitride (Si3N4) ceramics have special use value in the working environment of high temperature, high speed and strong corrosive medium due to its advantages of high specific strength, high specific modulus, high temperature resistance, oxidation resistance, wear resistance and thermal shock resistance. In recent years, domestic and foreign countries have competed to research and develop it, and its application range has been continuously expanded.

Because silicon nitride ceramics have such excellent properties, it is often used to make mechanical parts such as bearings, steam turbine blades, mechanical seal rings, and permanent molds. If silicon nitride ceramics are used to make engine parts, it can not only improve the quality of internal combustion engines and save fuel, but also my country, the United States, Japan and other countries have developed high refractory materials for diesel engines, such as Ni-SI3N4-BN materials and SI- SIC material is used for blast furnace shaft and other parts, while Ni-SI3-SN-SN is used for diesel engine furnace body, used for horizontal continuous casting separator, used for separator of molten steel, used for high strength, high precision, high Reliable, high-tech continuous casting.

Silicon nitride ceramics can be used in aerospace manufacturing. Aviation manufacturing is the most concentrated high-tech field in the manufacturing industry. It belongs to advanced manufacturing technology and is a leader in new materials, new processes and new technologies. Taking the turbine engine of an aircraft as an example, the application of silicon nitride in aviation manufacturing is explained. The application of aircraft Take the turbojet engine as an example. The temperature of the compressor components is below 650°C. At present, titanium alloy, aluminum alloy and heat-resistant steel are mainly used in the combustion chamber. The temperature in the combustion zone is as high as 1800-2000°C. Above 900 °C, it is usually made of high-temperature alloy (nickel-based and cobalt-based alloy) plates. In order to prevent gas erosion, thermal corrosion and heat insulation, a protective layer is often sprayed. Now, dispersion-strengthened alloys are used to prepare combustion chambers resistant to 1200 °C without coating. Mechanism ceramic silicon nitride is heat-resistant and can still have high strength and stiffness at 1400°C (but the mechanical strength will decrease when it exceeds 1200°C), but it is relatively brittle. Reinforced ceramics reinforced with continuous fibers can be applied to turbine components, especially It is the ceramic blade of the small engine, the outer ring of the turbine and the air bearing. In addition, the specific density of the silicon nitride ceramic is only 41% of that of the steel bearing, which can effectively reduce the weight of the aircraft engine and reduce fuel consumption.