What are the applications of silicon nitride ceramics

---

Silicon nitride ceramic is a kind of covalent bond compound composed of silicon and nitrogen, which has a series of excellent properties such as high temperature resistance, corrosion resistance, wear resistance, high toughness and high bending strength, and has a wide range of applications in many fields.

Machinery field

• Bearings: Silicon nitride ceramic bearing balls are one of the most widely used in the field of machinery. Compared with steel balls, silicon nitride ceramic bearing balls have the outstanding advantages of low density, high temperature resistance, self-lubrication, corrosion resistance, etc., and can be used in high-speed machine tool electric spindle high-speed bearings, aerospace engines, wind turbine bearings, automotive engine bearings and other equipment.
• Tools: Silicon nitride ceramics can be used to make high-speed cutting tools. Its high hardness and wear resistance enable it to maintain good performance during cutting, reduce tool wear, and improve machining efficiency and accuracy.
• Other mechanical components: Silicon nitride ceramics can also be used to make turbine blades, mechanical seal rings, permanent molds, etc. These components have excellent performance in high temperature and corrosive environments, which can improve the reliability and service life of mechanical equipment.

Aerospace

• Transparent material: Porous silicon nitride ceramics have relatively high flexural strength and lower density, as well as creep resistance, which can improve the stability of the structure at high temperatures. This material is used as a transparent material to make radome and antenna window. For example, Ceridan has shaped the silicon nitride radome on the PAC-3 missile.
  Engine components: Silicon nitride ceramics have higher strength, better creep strength and oxidation resistance than nickel-based heat-resistant alloys at temperatures above 1000 ° C, and have a small specific gravity, only 40% of that of heat-resistant alloys, which can meet the requirements of future aero-engines to reduce weight and fuel consumption.

semiconductor field

• Ceramic substrates: Silicon nitride ceramics have high thermal conductivity (typical values for commercial products are 80 to 90 W/mK). Compared with alumina substrates or ZTA substrates, their thermal conductivity is more than three times higher, and the thermal expansion coefficient (2.4 ppm/K) is small, close to semiconductor chips (Si, SiC), with good heat matching. In addition, silicon nitride ceramic substrates have excellent mechanical properties, taking into account high bending strength and high fracture toughness. Therefore, the current carrying capacity is high and the heat transfer performance is very good.
  Due to the excellent performance of silicon nitride substrates, they have a good application prospect in power modules (IGBT/SiC power modules) such as rail transit, wind power, photovoltaics, and new energy vehicles.

Bioceramics

• Implants: Silicon nitride ceramics have good biocompatibility and are widely used in implants such as biosensors, spine, orthopedics, dentistry, etc. For example, Amedica has developed a unique silicon nitride implant with very high comprehensive properties. According to official reports, taking SINTX in the United States as an example, silicon nitride spine materials have grown at a rate of 20% since 2012.
• medical apparatus: silicon nitride ceramics can also be used in the manufacture of medical apparatus, such as silicon nitride beads in islet transplantation machines. These beads improve the efficiency of pancreatic digestion, while preventing the pancreas from moving synchronously with the chamber system, and also increase the dispersion of pancreatic tissue within the chamber system.

Metallurgical field

• Thermal radiation protection tubes, burners, crucibles: Dense silicon nitride ceramics are mainly used in the metallurgical industry as thermal radiation protection tubes, burners, crucibles, etc. Its excellent high temperature resistance and corrosion resistance enable it to work stably for a long time in harsh metallurgical environments.

Ultrafine grinding field

• Grinding ball: Silicon nitride ceramics are covalent compounds, and their bonding mainly depends on the covalent bond between atoms. The prepared material itself has high hardness and wear resistance. In the ultra-fine powder and food processing industries, the performance of silicon nitride ceramic grinding ball is higher than that of traditional grinding ball, which has higher hardness and better wear resistance.

With its excellent properties, silicon nitride ceramics have shown great application potential and value in many fields. With the continuous improvement of preparation processes and the reduction of costs, its application range is expected to be further expanded, providing more powerful support for the development of various industries.