Silicon Nitride (Si₃N₄) Applied to Ceramic Product
Silicon nitride ceramics are highly resistant to heat, shock and impact. Excellent heat resistance and impact resistance coupled with high strength make silicon nitride a priority for high temperature, high load applications.
Common applications of silicon nitride ceramics: Semiconductor processing equipment, General industrial machinery, Heat-resistant parts.
Silicon nitride is an important structural ceramic material. It is a super-hard atomic crystal material with lubricity, and wear resistance. It features anti-oxidation at high temperature and resistance to thermal shocks. When heated to 1000°C or above in the air, rapid cooling before heating rapidly will not cause fragmentation of it. It is because of the excellent characteristics of silicon nitride ceramic, people often use it to make bearings, turbine blades, mechanical seals, permanent molds and other mechanical components. If the heating surfaces of engine components are made of silicon nitride ceramics that are resistant to high temperatures and not easy to transfer heat, it can improve the quality of the diesel engine, save the fuel and improve thermal efficiency. China, the United States, Japan and other countries have already developed such diesel engine.
Production of Silicon Nitride Ceramics
The production technology of silicon nitride ceramics has developed rapidly in the past few years. The production technologies mainly focus on the reaction sintering method, hot pressing sintering method, atmospheric sintering method and air pressure sintering method. The main types of silicon nitride production are air pressure sintering. Air pressure sintered silicon nitride is a high-performance scientific and technological ceramic material with ultra-high hardness and outstanding thermal shock resistance. Silicon nitride is far superior to other ceramic materials in terms of high temperature resistance, and at the same time it has excellent properties such as oxidation resistance, strength and creep resistance. In addition, silicon nitride has its own low thermal conductivity and high wear resistance so that it can be applied to the most demanding environments. In terms of acid and alkali corrosion resistance, in addition to hydrofluoric acid, it does not react with other inorganic acids with strong anti-corrosion ability and anti-oxidation under high temperature.
Characteristics
In addition to hydrofluoric acid, it does not react with other inorganic acids (the reaction equation: Si₃N₄ + 12 HF3 SiF4 ↑ + 4 NH3 ↑) with strong anti-corrosion ability.
- Silicon nitride ceramic materials features precision ceramic materials with high temperature strength and great thermal shock resistance.
- Excellent mechanical strength and high temperature resistance.
- Small thermal expansion coefficient and better thermal shock resistance.
- Chemical stability, wear resistance, excellent corrosion resistance.
- It can be stably used when heated to 1200 degrees in acid gas environment.
Application Of Silicon Nitride
Silicon nitride is used as advanced refractory materials. For example, it's used for blast furnace and other parts with SIC as Si₃N₄-SIC refractory material; and used for horizontal continuous casting separation ring combined with BN as Si₃N₄-BN material. Si₃N₄-BN series horizontal continuous casting separation ring is a fine structure ceramic material with uniform structure and high mechanical strength. It enjoys good thermal shock resistance and will not be wetted by liquid steel, which is in line with the casting technology requirements.
Main Performance Data of Silicon Nitride Ceramic
| Material | - | Si₃N₄ |
|---|---|---|
| Sintering Method | - | Gas Pressure Sintered |
| Density | g/cm³ | 3.22 |
| Color | - | Dark Grey |
| Water Absorption Rate | % | 0 |
| Young Modulus | Gpa | 290 |
| Vickers Hardness | Gpa | 18 - 20 |
| Compressive Strength | Mpa | 2200 |
| Bending Strength | Mpa | 650 |
| Thermal Conductivity | W/m.K | 25 |
| Thermal Shock Resistance | Δ (°C) | 450 - 650 |
| Maximum Operating Temperature | °C | 1200 |
| Volume Resistivity | Ω·cm | > 10 ^ 14 |
| Dielectric Constant | - | 8.20 |
| Dielectric Strength | kV/mm | 16 |
* Tests under room temperature environment;
* The above information is offered for comparison only. Exact
Silicon Nitride (Si₃N₄)
Gallery
Silicon Nitride (Si₃N₄) Precision Ceramic Processing
Silicon Nitride (Si₃N₄) Precision Ceramic Processing
Silicon Nitride (Si₃N₄) Precision Ceramic Processing
Silicon Nitride (Si₃N₄) Precision Ceramic Processing