Brief introduction of silicon carbide products

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Introduction to silicon carbide products
Silicon carburide also known by the names moissanite or emery is an inorganic material with a formula of SiC. It is produced by melting quartz sand with wood chips, coke or petroleum coke. In nature, silicon carbide is found in the rare mineral moissanite. It is the most popular and cost-effective refractory material among the non-oxide materials like C, N, and B. It can also be called refractory or gold steel. In China, silicon carbide is made up of two types: green and black. They are both hexagonal crystals and have a specific gravity ranging from 3.20 to 3.25.

Both black silicon carburide and green silica carbide belong to the aSiC. Black silicon carbide has a SiC content of 95% and is more durable than green silicon carbide. It is used to process materials that have low tensile strengths, like glass, ceramics or stone. Green silicon carbide has a SiC content of over 97% and is self-sharpening. It is used primarily for the processing of cemented carbide (a titanium alloy), optical glass and titanium alloy. Also, it can be used for honing and fine grinding tools made from high-speed steel and for cylinder liners. There is also a cubic silicon-carbide, which is yellow-green crystals prepared through a special method. The abrasive tools used to make them are suitable for superfinishing bearings. Surface roughness is processed between Ra320.16microns and Ra0.040.02 microns.

Aside from being an abrasive, silicon carbide can be used in many other ways. This is due to its chemical stability, high thermal conductivity (low thermal expansion coefficient), and wear resistance. The powder of silicon carbide can be used to coat a specific impeller, cylinder or other part of a turbine. The inner wall of the refractory can be improved to increase its resistance to abrasion and its life span by upto 2 times. Low-grade Silicon carbide (containing about 85% SiC), which is a deoxidizer of excellent quality, can improve the steelmaking process and speed. It also allows for better control over chemical composition. Besides, silicon is used in the manufacture of silicon carbide for electric heater elements.
It is the second hardest substance in the world, after diamonds (10). It has excellent heat conductivity and is a semi-conductor.

There are at least 70 crystal forms of silicon carbide. Allomorphs of silicon carbide are the most common. It has a hexagonal crystalline structure and is formed above 2000 degC at high temperatures. Below 2000 degC b Silicon Carbide with cubic crystals, similar to Diamond, is formed. On the page is a network. It is eye-catching due to its larger surface area unit than the a catalyst type, even though heterogeneous catalyst support is used. A type of silicon carburide called m-silicon is more stable, and it produces a pleasing sound when it collides. However, until now these two types had not been used commercially.
Due to its high sublimation temp (approximately 27°C) and 3.2g/cm3 specific weight, silicon carbide makes a great raw material for bearings and high-temperature ovens. It does not melt at any pressure, and it has a very low chemical activity. Its high thermal conductivity and breakdown electric field strength as well as its high maximum current densities have led many to try and use it in place of silicon for high-power semiconductor components. It has a high coupling effect to microwave radiation.
The color of pure silicon carbide, however, is black or brown when produced industrially. This is due to iron impurities. The silica coating on the surface of the crystal gives it a rainbow-like appearance. To

Pure silicon carbide is a transparent, colorless crystal. The impurities in industrial silicon carbide cause it to be light yellow or green. It can also be blue, black, or dark brown. Its clarity varies according to its purity. The cubic silicon carburide (called cubic silica carbide) and hexagonal rhombohedral or hexagonal a-SiC crystal structures are the two main types of silicon carbide. The different stacking of silicon and carbon atoms creates a variety of a SiC variants. Over 70 types have been identified. Above 2100degC bSiC turns into aSiC. Industrial silicon carbide is produced by refining petroleum coke and high-quality sand in a resistance oven. The silicon carbide blocks that have been refined are crushed and then subjected to acid-base washing, magnetic separation, sieving, or water selection.
It is artificial because silicon carbide has a low natural content. The standard method involves adding wood chips and salt to coke. It is then heated to 2000degC in an electric kiln.
Its excellent hardness has made it an indispensable abrasive, but its range of application is much wider than that of general abrasives. Due to its thermal conductivity and high-temperature resistance, it is a popular choice for kiln furniture in tunnel kilns. The electrical conductivity of this material makes it a vital electric heating element. SiC products can be prepared by first preparing SiC smelt block [or SiC Pellets, as they contain C but are very hard and were previously called: emery. It is not natural emery, also known as garnet. In the industrial production of SiC, quartz, petroleum coal, etc. is usually used. As raw materials, as auxiliary recovery material, or as spent materials. After grinding or other processes, the materials are blended to a charge that has a reasonable particle size and ratio to adjust its gas permeability. An appropriate amount must be added. To prepare green silicon carbide at high temperatures, you need to add the correct amount of sodium chloride. Special silicon carbide electric heaters are used for the thermal equipment to prepare SiC smelting at high temperatures. Its main components are the bottom of furnace, end wall with electrodes inside, removable sidewalls and furnace core body. Both ends are electrode-connected. This electric heater uses what is known as buried-powder firing. As soon as you turn it on, the heating begins. The furnace core is at 2500degC (or even higher, between 2660-2700degC). SiC is produced when the charge reaches approximately 1450degC (but SiC forms mainly at temperatures >=1800degC). SiC decomposes when the temperature is >=2600. The decomposed si, however, will form SiC and C in the charged.
Each electric heater is equipped with transformers. Even so, during production only one electric heater is operated to adjust voltage according to electrical load characteristics in order to maintain constant electricity. The high-power electric furnace needs to be heated for about 24 hours. After a power failure, the reaction of generating SiC is over. After a cooling period, the sidewall can be removed, and then the charge is gradually taken out. Silicon carbide products can be divided into many categories and are divided into different categories according to different use environments and generally used on machinery more. For example, when used on mechanical seals, it can be called a silicon carbide seal ring, which can be divided into the static ring, moving ring, flat ring and so on. We can also produce various shapes of silicon carbide products according to customers’ special requirements, such as silicon carbide special-shaped parts, silicon carbide plates, silicon carbide rings, etc.
Silicon carbide ceramics, one of the silicon carbide products, has the characteristics of high hardness, high corrosion resistance, and high-temperature strength, which makes silicon carbide ceramics widely used.
Applied to seal ring: Silicon carbide ceramic has good chemical resistance, high strength, high hardness, good wear resistance, low friction coefficient, and high-temperature resistance, so it is an ideal material for manufacturing sealing rings. When paired with a graphite material, its friction coefficient is smaller than that of alumina ceramics and cemented carbide, so it can be used for high PV values, especially in the working conditions of transporting strong acids alkalis. The SIC-1 silicon carbide atmospheric sintered products produced by our company have the characteristics of high density, high hardness, large production batches, and the ability to make products with complex shapes. They are suitable for high-performance seals, exceptionally high PV values and Resistant to strong acids and alkalis. The SIC-3 silicon carbide ceramic works produced by our company are graphite-containing silicon carbide materials. Since the silicon carbide matrix contains many dispersed fine graphite particles when paired with other materials, its friction coefficient is minimal. It has good self-lubricating properties, which is especially suitable for making air-tight dry-friction seals. It is used in the medium so that the seal’s service life and the work’s reliability are improved.

The furnace charge after high-temperature calcination is unreacted material (for heat preservation in the furnace), silicon carbide oxycarbide (semi-reactive material, the main components are C and SiO. ), the binder layer (for bonding Very tight material layer, the main element is C, SiO2, 40% to 60% SiC and Fe, Al, Ca, Mg carbonate), amorphous material layer (the main component is 70% to 90% SiC, and it is Cubic SiC is b-sic, and the rest are C, SiO2 and carbonates of Fe, Al, Ca, and Mg), second grade SiC layer (the main component is 90%-95% SiC, the coating has formed hexagonal SiC, namely the mouth One SiC, but the crystal is small and fragile, and cannot be used as an abrasive), the first-class SiC layer (SiC content <96%, and it is hexagonal SiC that is a coarse crystal of SiC), furnace core graphite. Among the layers as mentioned above, the unreacted material and a part of the oxycarbide layer material are usually collected as spent material, and the other part of the oxycarbide layer material is collected together with the amorphous material, the second-grade product, and part of the bonded material as recycled material. Charges and some bonds with tight bonding, large lumps and many impurities are discarded. The first-grade product is classified, coarsely crushed, finely crushed, chemically treated, dried and sieved, and magnetically separated into black or green SiC particles of various sizes. To make silicon carbide powder, it must go through a water selection process; to make silicon carbide products, it must go through forming and sintering.

( Tech Co., Ltd ) is a professional Silicon carbide manufacturer with over 12 years of experience in chemical product research and development. If you are looking for high-quality Titanium dioxide, please feel free to contact us and send an inquiry.