Silicon Nitride Ceramic
Featured Product from Xiamen Unipretec Ceramic Technology Co., Ltd.
Silicon Nitride ceramic offers both outstanding mechanical strength and extraordinary thermal shock resistance. So it’s an ideal material when dynamic stress and thermal rigor are required. Compared with most metals, Silicon Nitride can withstand higher temperature, resist oxidation and corrosion, and has properties of high wear resistance. With all this combination of properties, Silicon Nitride is broadly used for high-temperature and high-stress applications which require great mechanical strength along with excellent corrosion and wear resistance.
Material Properties
- High fracture toughness;
- High strength at high temperature;
- Good flexural strength;
- Exceptional hardness, abrasion resistant;
- Low density-low weight compared with steel;
- Excellent thermal shock resistance;
- Low thermal expansion;
- Electrical resistivity;
- Chemical inertness.
There are several different methods used to produce Silicon Nitride. Materials produced by different method are slightly different. Here introduced two popular methods: gas over-pressure sintering and hot isostatic pressing.
Gas Over-Pressure Sintered Silicon Nitride Ceramics
This is the most popular method to produce Si3N4 components with high toughness, high strength and various complex shapes. This method sinters silicon nitride compact in 5-12MPa nitrogen at 1800-2100°C. Due to the high-pressure nitrogen atmosphere, the decomposition temperature of Si3N4 is increased, which is conducive to the selection of sintering aids that can form intergranular phases with high refractoriness to improve the high temperature performance of the material.
Hot Isostatic Pressed Silicon Nitride Ceramics
The mixture powder of silicon nitride and sintering aid is packaged in a metal or glass sheath, and sintered at high temperature through high-pressure gas after vacuuming. The commonly used pressure is 200MPa and the temperature is 2000°C. Hot isostatic pressing of silicon nitride can remove any pores from the material and reach the theoretical density, which results in greater hardness and toughness. But this process is complicated and costs high.
Applications
Turbines and high-end bearing balls
Ball valve components
Mechanical seal faces
Induction heating coil supports
Welding guide Pins, welding fixture
Heating Element components
Metal tube welding roller cam roller
TIG welding nozzle, plasma welding nozzle
High wear rod and shaft
Thermocouple protection sheath, riser tube
Insulating heat dissipation substrate
Crucibles
