Silicon carbide is a ceramic material with wide application prospects. It is composed of carbon and silicon element materials. It has a very high melting point and solidification degree, and also has excellent heat, electrical properties and chemical stability. With the development of science and technology, silicon carbide has been widely used in various fields, especially in high temperature, high pressure, high speed and strong corrosion environments with sudden performance. Grinding, machinery, semiconductor and other areas have important applications.
Advantage
| Advantage | Feature |
| High hardness | The hardness is 9.0~9.5, which is close to diamond, and has good scratch resistance and wear resistance. |
| High melting point | The melting point reaches about 2700°C, and it has good heat resistance in high temperature environments. |
| High corrosion resistance | It has good corrosion resistance to many chemical media, and is not easily corroded by acid, alkali and other media. |
| Excellent thermal stability | Capable of maintaining stable performance at high temperatures, not easily deformed or damaged. |
| Excellent electrical properties | It has good electrical insulation and semiconductor properties, and can still maintain good electrical properties in high temperature environments. |
| High thermal conductivity | The thermal conductivity is several times or even dozens of times that of traditional metal materials, making it have good heat dissipation at high temperatures. |
| Excellent mechanical properties | It has good tensile strength and compressive strength, but also has good toughness and fracture toughness. |
Disadvantage
| Disadvantage | Feature |
| Fragility | The high temperature and brittleness make it prone to fracture or breakage, so special care is required in the manufacturing process. |
| Difficult to process | Density and sensitivity make it difficult to process into complex shapes or small sizes. |
| Expensive Manufacturing Results | The manufacture of silicon carbide requires special conditions such as high temperature and high pressure, plus the need to prevent oxidation and other pollutants during the manufacturing process, resulting in higher manufacturing costs than other materials. |
| Insufficient raw materials | The manufacture of silicon carbide requires the use of high-purity silicon carbide and graphite. The supply of these raw materials is limited, so the cost of manufacturing silicon carbide is relatively high. |
Crystal structure
α-SiC
The crystal structure is similar to that of graphite, which is formed by alternating layers of carbon atoms and silicon atoms with a layered structure. Due to the longer bond length between carbon atoms and silicon atoms, α-type silicon carbide is more prone to defects than β-type silicon carbide, so its properties are not as stable as β-type silicon carbide.
β-SiC
The crystal structure is hexagonal, and its unit cell structure consists of two atoms of silicon and carbon. Silicon atoms and carbon atoms are alternately arranged to form a hexagonal closest-packed crystal structure. Due to the presence of carbon-silicon bonds, its structure is more stable than diamonds, and it has many excellent physical and chemical properties, such as high hardness, high melting point, High corrosion resistance etc.
Preparation
1. Chemical vapor deposition method
A method of preparing silicon carbide thin films and crystals by gas phase reaction. The silicon source and the carbon source are mixed together and reacted under high temperature and high pressure gas pressure so that they are deposited at the bottom to form silicon carbide crystals.
2. Carbothermal reduction method
A method of mixing carbon stone and silicon carbide and reacting at high temperature to make carbon hot stone and carbon carbon react to form silicon carbide. This method requires a high temperature and long reaction process, and the manufacturing cost is extremely high.
3. Silicon thermal reduction method
The method of mixing silicon dioxide and graphite and reacting at high temperature to make silicon dioxide and graphite react to form silicon carbide. This method requires high temperature and long-time reaction process, and the production cost is relatively high.
4. Sol-gel method
A method of forming carbonized silicon gel under a suitable strip through the interaction of sol and gel. Through processes such as dry firing and burning, the silicon carbide material is shaped.
Application in grinding
1. Abrasive
It can be made into various abrasive materials, such as sandpaper, grinding wheel and cutting disc, etc. Silicon carbide abrasive has high temperature, wear resistance and high temperature stability, so it can work under high speed, high temperature and high load grinding conditions.
2. Grinding liquid
Silicon carbide abrasive has high temperature stability and chemical properties, so it can be used in high temperature, high pressure and humic environments.
3. Grinding tools, ceramics
It has high temperature, high temperature grinding resistance and high temperature stability, so it can work under high speed, high temperature and high load grinding conditions, such as grinding heads, grinding sheets, grinding ingots, etc.
Other Application
| Industry | Feature | Apply to |
| Electronic | 1. High current conductivity, high electron mobility and high thermal stability and other characteristics. 2. Improve conversion efficiency and reduce device damage performance. | Semiconductor devices, functional modules, high-frequency devices and optoelectronic devices, etc. |
| Mechanical | Density and strength make it an important representative of high-performance ceramics. | Manufacture of highly loaded bearings, mechanical seal parts and cutting tools, etc. |
| Chemical Industry | Corrosion resistance and high temperature resistance make it an important corrosion-resistant material. | Chemical equipment, catalysts and electrochemical cells. |
| Aviation | Altitude, high temperature and high temperature resistance become a sane aerospace material. | Manufacture of incoming engine components, thermal structural materials and heat-resistant paint layers, etc. |
| Energy | High-temperature thermal conductivity and high-temperature stability make it a sensible material for high-temperature management. | Solar panels, thermal battery materials and nuclear reactors, etc. |
Conclusion
As an important advanced material, silicon carbide has been widely used in various fields. It has excellent characteristics such as high temperature, wear resistance, high temperature resistance, high temperature resistance, high chemical stability, etc., forming an ideal choice for high temperature, high speed, high load and corrosive environments. At the same time, silicon carbide also has excellent thermal conductivity and electrical conductivity, making it widely used in electronic equipment, solar cells and semiconductors. However, silicon carbide also has some disadvantages, such as high manufacturing difficulty and relatively high cost, which limit its application in some fields. It is believed that through continuous innovation and technological advancement, silicon carbide will play a more important role in the future.
Picture Resource:https://www.fsabr.com/abrasive-grains-silicon-carbide
