Silicon nitride is a gray ceramic with high fracture toughness, excellent heat shock resistance, and relatively impenetrable properties to molten metals.
Using these characteristics, it is applied to internal combustion engine parts such as automobile engine parts, welding machine blowpipe nozzles, etc., especially parts that need to be used in harsh environments such as overheating.
With its high wear resistance and high mechanical strength, its applications in bearing roller parts, rotating shaft bearings and semiconductor production equipment spare parts are constantly expanding.
Properties of silicon nitride ceramics
1, has a high strength in a large temperature range;
2, high fracture toughness;
3, good bending strength;
4, resistance to mechanical fatigue and creep;
5, light - low density;
6, high hardness and wear resistance;
7, excellent thermal shock resistance;
8, low thermal expansion;
9, electrical insulator;
10, good oxidation resistance;
11, good chemical corrosion resistance.
Silicon nitride ceramics have low thermal expansion coefficient and high thermal conductivity, so they have excellent heat shock resistance. The hot-pressed sintered silicon nitride will not break after being heated to 1000℃ and put into cold water. At not too high a temperature, silicon nitride has a high strength and impact resistance, but above 1200℃ will be damaged with the growth of use time, so that its strength is reduced, more prone to fatigue damage above 1450℃, so the use of Si3N4 temperature generally does not exceed 1300℃.
Therefore, silicon nitride has been widely used in:
1. Rotating ball and roller bearings;
2. Engine components: valve, rocker arm pad, sealing surface;
3. Induction heating coil bracket;
4. Turbine blades, blades, buckets;
5. Welding and brazing fixtures;
6. Heating element assembly;
7. Welding positioner;
8. Precision shafts and sleeves in high-wear environments;
9. Thermocouple sheath and tube;
10. Semiconductor process equipment.
