Silicon nitride ceramics have been widely used in aerospace and military industry, mechanical engineering, communications, electronics, automobiles, energy, chemical biology and other fields because of their high temperature resistance, corrosion resistance, wear resistance and unique electrical properties.
Especially in the field of high temperature structural ceramics, silicon nitride ceramics are new materials with the best comprehensive properties, most possibly to replace nickel-based alloys.
Application in Aerospace & Military Industry
Taking the turbojet engine of an aircraft as an example, the temperature of the compressor parts is below 650 ℃, and currently titanium alloys, aluminum alloys and heat-resistant steels are mainly used. The temperature in the combustion zone of the combustion chamber is as high as 1800-2000 °C. After the introduction of air cooling, the wall temperature of the combustion chamber is still above 900 °C. , The protective layer is often sprayed, and the dispersion-strengthened alloy can be used to prepare a 1200 ℃ natural burning chamber 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. The use of continuous fiber reinforced reinforced ceramics can be used in turbine components, especially It is the ceramic blades of the small engine, the outer turbine ring and the air bearing. In addition, the specific density of silicon nitride ceramics is only 41% of that of steel bearings, which can effectively reduce the weight of aircraft engines and reduce fuel consumption.