The basic structure of silicon nitride ceramics is [SiN4] tetrahedron, which is a solid two-continuous network structure, and is an inorganic ceramic material that does not shrink during sintering. Silicon nitride ceramics have the characteristics of high strength, low density and high temperature resistance.
Silicon Nitride Ceramics
Advantages of silicon nitride ceramics:
Silicon nitride ceramic is a super hard substance and an insulating material. It has lubricity, wear resistance, strong corrosion resistance, and oxidation resistance at high temperature. It can also resist thermal shock. According to the experimental results: silicon nitride ceramics are heated to above 1,000 ℃ in the air, and then rapidly cooled and then heated rapidly, and they will not break. It can be seen that silicon nitride ceramics have high strength, wear resistance, oxidation resistance and corrosion resistance. Silicon nitride ceramics have low density and light weight characteristics.
Disadvantages of silicon nitride ceramics:
The fracture toughness coefficient is low, and the mechanical strength in ceramics is medium and low, and it is easily cracked and brittle. Compared with aluminum oxide and aluminum nitride, it is not easy to transfer heat. The thermal conductivity is worse than that of aluminum nitride, and the heat transfer performance is worse than that of alumina.
Application of silicon nitride ceramics:
1. High temperature bearings, mechanical seal rings, pipes and valves of electromagnetic pumps for conveying molten aluminum;
2. Mechanical components such as gas turbine blades, mechanical seal rings, permanent molds, etc.;
3. Diesel engine ignition device, engineering structural ceramics, etc.
4. Nitride ceramic copper clad substrate, used in automotive inverters, reducers, shock absorbers and other applications.
Si3N4 silicon nitride ceramics have excellent comprehensive properties and are an ideal high-temperature structural material with wide application fields and markets. At the same time, silicon nitride ceramics are ceramic materials with wear resistance, corrosion resistance and high temperature resistance that are difficult to compare with general metal materials. , oxidation resistance, thermal shock resistance and low specific gravity. It can withstand the harsh working environment that metal or polymer materials are incapable of, and has a wide range of application prospects.