Silicon nitride is a durable and strong ceramic material with many unique characteristics. It has vast applications in many industrial tools and equipment.
The most impactful uses of silicon nitride are in the automotive industry, aerospace engineering, bearing manufacturing, electronic industry, biomedical equipment, dental implants, etc.
The outstanding physical and chemical properties have made it the best replacement for the traditional materials in those fields. Let’s dive in and explore the silicon nitride uses in detail.
What is Silicon Nitride?
Silicon nitride is a thermodynamically stable, solid, chemically inert, white color, non-metallic chemical compound. It consists of three silicon and four nitrogen atoms. The silicon nitride formula is Si3N4. It is one of the most important industrial nitrides.
The silicon nitride is made from the chemical reaction of powdered silicon kept in a nitrogen atmosphere at around 1400 degrees centigrade temperature. The chemical reaction is:
3Si+ 2N2= Si3N4
The compound was first introduced in 1857 and the first synthetic silicon nitride was innovated by Deville and Wohler after two years of the compound’s introduction in 1859.
It was used as structural ceramic in the 1970s and internal combustion engines and gas turbines in the 1980s.
The properties, processing, and synthesis of Si3N4 were vastly studied throughout several years after that. As a result, commercial silicon nitride use has increased significantly in recent years.
There are different types of silicon nitride-based materials available such as:
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RBSN (reaction-bonded silicon nitride),
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HPSN (hot-pressed silicon nitride ),
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SRBSN (sintered reaction-bonded silicon nitride),
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SSN(sintered silicon nitride), PSSN(partial pressure sintered silicon nitride)
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and HIPSN (hot isostatically pressed silicon nitride).
Key Silicon Nitride Properties: Silicon nitride ceramic has amazing properties that make it suitable for different advanced engineering applications. Learning about these properties will help you understand the uses of it. The major silicon nitride properties are:
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Low density
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High mechanical strength and toughness
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High thermal shock resistance
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Excellent thermal stability
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Excellent wear resistance
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Low coefficient of thermal expansion
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Superior thermal shock resistance
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Good oxidation resistance
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And fracture toughness.
Top Silicon Nitride Uses in Modern Industries:
Silicon nitride is one of the most used structural ceramics materials for different equipment, appliances, and parts. The most influential applications of silicon nitride are:
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Engine Manufacturing: Silicon nitride is used widely in manufacturing different reciprocating engines, spark-ignited engines, and diesel engine parts. It is also used in the automobile engine industry where failure is not severe.
The silicon nitride-made diesel engine parts are glow plugs, precombustion chambers(or swirl chambers), and turbochargers. The SiN4 diesel engine turbocharger has lower inertia that reduces the engine lag and exhaust emissions.
The silicon nitride spark-ignited engine parts are rocker arm pads, turbochargers, and exhaust gas control valves. This exhaust gas control valve increases the acceleration and the rocker arm pad reduces the wear of the engine.
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Bearings Industry: The fully densified silicon nitride material is wear-resistant, less frictional,highly stiff, and stable in high temperatures. Hence, the HPSN(hot-pressed silicon nitride) is commonly used in bearing production. These dense Si3N4 boost the operational performance of lubrication-less ball and roller bearings.
The ceramic bearing is not affected by electric fields, magnetic fields, and corrosion. These bearings have a longer life, higher corrosion resistance, and better speed than conventional materials like steel bearings. Ceramic bearings are used in the machines and junctions where metal-made bearings are prohibited.
Most of the silicon nitride bearings are hybrid ball bearings of steel races and ceramic balls. These hybrid bearings are used for vacuum pumps, dental drills, and machine tool spindles.
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Aerospace Industry: Conventional materials like composites and metals have been used in aircraft production for a long time. However, they are not sustainable in extreme temperature, pressure, and corrosion of hypersonic flight vehicles.
Hence, the advanced aerospace industry requires more robust, lightweight, high-strength, corrosion-resistant, temperature-resistant, and stable materials like ceramics.
The mechanical strength and robustness of the ceramic silicon nitride make it suitable for RF windows, ball bearings, and radomes. More research, development, and customization are required to use the material vastly in aerospace.
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Electronic Appliances Manufacturing: Silicon nitride has unique electrical properties, making it a popular material for the microelectronics industry as a chemical barrier and insulator. It is used in Integrated Circuits (ICs) and the protective packaging of highly sensitive electronic devices.
Silicon nitride does not take part in the chemical reactions with the sodium ions and water. It works as a passive layer and diffusion barrier in microelectronic devices.
Ceramic silicon nitride is also used as the electrical insulator in the capacitors of the analog chip. It has applications in optic signal processing, biochemical and biomedical optics, biophotonics, data communication, and telecommunication due to its broadband nature.
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Welding Industry: The silicon nitride si3n4 is replacing the use of conventional steel in electric resistance welding. The silicon nitride-made welding rollers are popular in the welding industry. The hardness, strength, and thermal shock resistance have made it an essential material for this industry.
Silicon nitride-made welding tools are efficient, long-lasting, and need less maintenance than other metal-made tools. If you want improvements in your welding equipment, use the Si3N4 products.
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Biomedical Industry: Silicon nitride has special properties like biocompatibility, anti-bacterial characteristics, chemical sterilization, radiolucency, lightweight, wear and corrosion resistance, and mechanical strength. These properties have made it an ideal material for biomedical use.
The biocompatibility ensures the silicon nitride does not show any side effects when implemented in the human body. It has excellent resistance to biofilm formation and bacterial growth that prevents infections around the implants.
The osteoconductivity of silicon nitride helps to form the bone. That is why, the material is used in dental, orthopedic implants, and wound care. It is also used in fracture fixation devices.
The exceptional mechanical strength of silicon nitride allows for enduring high stresses and heavy loads as a replacement for the spine and joints. The resistance to wear and corrosion ensures the longevity of the implants. It also reduces the ions and debris-releasing possibility in the body.
The radiolucency of the silicon nitride allows better postoperative monitoring through X-rays and CT scans. Because it does not obstruct those imaging processes like the metal implants.
After all, silicon nitride elements help medical professionals detect and heal potential complications more effectively.
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Biosensor: The silicon nitride application in biosensor technology has solved the problems associated with the sensitivity, stability, and size of optical biosensors.
It can further develop the efficacy of in-vivo and in-vitro diagnostics. The top-grade mechanical and electrical properties of silicon nitride have made it an excellent material for the biosensor industry.
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Dental Uses: Different influential properties have made Si3N4 perfect for dental use.
The American Ceramic Society has marked silicon nitride as the “killer ceramic material” for its antibacterial properties. It can suppress porphyromonas gingivalis bacteria raised in the oral cavities. This bacteria is the reason for gum disease.
The silicon nitride can break up the biological structure of the bacteria and can damage them by destroying the molecules, DNA, and protein of the cells.
The silicon nitride-made dental crowns, bridges, and veneers have appearances like a real tooth. These Si3N4 dental elements can endure repeated contact with other teeth and mechanical stress.
The chemical stability of the silicon nitride dental elements resists their degradation in the oral environments from saliva, acids, and other chemicals. They don’t react or corrode like materials and ensure longevity.
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Possible Future Uses: There are huge chances of using ceramic silicon nitride in different industries. The most likely fields are advanced aerospace applications, nuclear energy, healthcare, biomedicine, high-power electronics, electric vehicles, renewable energy, and 3D printing.
More extensive research and development on silicon nitride materials will make that use possible soon.
FAQs
Some frequently asked questions will assist you more in learning about the silicon nitride uses. The most common questions on the topic are:
Q1: What is the use of silicon nitride in CMOS fabrication?
Silicon nitride is used as the dielectric layer, oxidation barrier, passivation layer, etch stop layer, stress engineering, spacer material, hard mask, etc in CMOS (Complementary Metal-Oxide-Semiconductor) fabrication.
Q2: What is the work function of silicon nitride?
The work function of a material means the minimum energy required to move an electron from the material surface. The work function of the silicon nitride is not fixed. It varies on the manufacturing environment and the materialistic properties.
The work function of silicon nitride is between 4.2 eV to 5.2 eV.
Q3: What are the uses of nitride?
Nitride materials are widely used for their chemical resistance, high hardness, and thermal stability. Some of the most used nitride materials are silicon nitride, boron nitride, lithium nitride, titanium nitride, and gallium nitride.
These nitrides are used in electronics, semiconductors, abrasives, cutting tools, protective coatings, light emitting devices, aerospace, and automotive industry.
Q4: What is the density of silicon nitride?
The density of silicon nitride is 3.17 g/cm3 (gram per cubic centimeter). It can vary between 2.37 to 3.25 g/cm3 for the production process. The density of the Si3N4 is an important parameter for many applications like nuclear physics.
Conclusion: So, friends, it’s time to sum up! We have covered the important uses of silicon nitride in different fields. I hope you enjoyed reading the article and gathered the knowledge, that will assist in your professional activities.
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