Nowadays silicon carbide is widely used in semiconductor products. Silicon carbide has appeared in many high-tech industries such as smart grid, rail traffic, electric automobile, cellphone, etc. While today the article plans to introduce the traditional applications of silicon carbide you may ignore.
Silicon carbide description
Silicon Carbide (SiC) is a typical polycrystalline compound. It is made of silica sand, petroleum coke, wood chips as raw materials smelted in a resistance furnace. There are α-Silicon Carbide and β-Silicon Carbide.
α-SiC is used as abrasive material, which is divided into black silicon carbide and green silicon carbide.
β-SiC is used as raw material for SiC ceramics.
4 astonishing applications of silicon carbide
Silicon carbide is widely used in the metallurgy industry, refractory industry, chemical industry, abrasive tool making, and so on.
1. Silicon carbide used in steel making
Silicon carbide is used as deoxidizing agent, purifying, and modifying agent in steelmaking. Silicon carbide resolved in the molten steel and react with oxygen to form CO and furnace slag. It can shorten the deoxidizing time, reduce the energy cost, improve the quality of steel, reduce the raw materials consumption, reduce environmental pollution and improve the working condition. Silicon carbide is a new type of deoxidizer, it replaces the traditional deoxidizer silicon-carbon powder. Compared with traditional technology, SiC chemical properties are more stable, and deoxidizing effect is good.
The advantages of silicon carbide in steelmaking are as follows.
- Silicon canbide can replace the ferrosilicon, and it is put in the furnace without occurring dust polution, rapid reaction speed and cost down. It is a new type during smelting steel.
- Silicon carbide can reduce the metallic oxide (Feo, MnO) in the molten steel, and reduce the lining wear and increase steel output.
- Silicon carbide releases heat when oxidized, which reduce the energy consumption.
- Lowest cost silicon unit and also has a carbon benefit.
2. Silicon carbide used in refractory industry
Silicon carbide is widely used as high-performance refractory material because it has the advantages of low thermal expansion coefficient, high thermal conductivity, high-temperature strength, etc. According to the different bonding phases, SiC products can be divided into oxide-bonded SiC, nitride-bonded SiC, self-bonded SiC, siliconized reaction sintered SiC, etc.
- Al2O3-SiC-C
In 1999, Wang Xitang and other scientists researched and developed Al2O3-SiC-C self-flowing castable refractory for blast furnace tapping channel. The castable has high strength, good corrosion resistance, and good thermal shock resistance and oxidation resistance.
The most common application of SiC in unshaped refractories is the liner of blast furnace tapholes. At present, Al2O3-SiC-C castables are widely used in larger blast furnaces all over the world, which greatly extends the service life of the tapping channels.
In addition, SiC-containing refractories are also widely used in molten iron pretreatment linings, cupolas and induction furnace linings in the iron and steel industry, combustion chamber sidewall linings and boiler tube protection linings of garbage incinerators; cement kilns in the cement industry Preheater lining; cyclone lining of the thermal power plant, combustion chamber, lining and high-temperature separator of circulating fluidized bed furnace, firing kiln slab and silicon outlet and aluminum outlet of ceramic industry, etc.
- Si3N4-SiC
Adding silicon carbide to clay clinker can improve thermal shock resistance, thermal conductivity, and strength. The greater the amount of silicon carbide powder added, the higher the thermal shock resistance.
Adding a suitable amount of phosphoric acid in the high-aluminum silicon carbide product(SiC30%), can improve the thermal shock resistance, thermal conductivity, and hardness. Adding a little SiC fine in corundum silicon carbide product can improve the thermal shock resistance. For example, using brown corundum as aggregate, adding 10% SiC fines and phosphoric acid, after high-pressure forming, and heat treatment at 1450℃, the slide brick for the rolling furnace is produced, the application effect is good.
3. Silicon Carbide Used For Abrasive Material
Silicon Carbide has high hardness, chemical stability, high toughness. Silicon Carbide is second only for a diamond in hardness. Its abrasive resistance is 5-20 times that of cast iron and rubber. So it is one of the most ideal materials for Airstrip, and it is used for making glass, ceramics, dimension stone, cast iron, ferrous or non-ferrous, hard ferroalloy, Ti ferroalloy, high-speed cutter, and grinding wheel, etc.
- In China, green silicon carbide is mainly used as an abrasive material. The abrasive tools made of green silicon carbide are mainly used to grind cemented carbide, titanium alloy, and optical glass. They are also used for the honing of cylinder liners and the fine grinding of high-speed steel tools.
- Black silicon carbide is used to produce abrasive tools, which are mainly used to cut and grind materials with low tensile strength, such as glass, ceramics, stones, and refractories. It is also used to grind cast iron components and nonferrous metals.
- Cubic silicon carbide abrasive tool usually used in the super grinding of micro bearing. The water turbine coating with the silicon carbide powder can improve the abrasive resistance of the impeller. The cubic silicon carbide powder pressed in the cylinder wall of the internal combustion engine can double the working life of the internal combustion engine.
4. Silicon carbide used in semiconductor industry
SiC semiconductor fit for “extreme environment”. Supposedly, the silicon carbide wafers even can withstand the high temperature near the Sun and Venus. Research shows that even under the condition of 560℃. Silicon Carbide wafer can run well without a cooling site.
Silicon carbide wafer has a broad prospect in communications. It makes it possible to let the HDTV transmitter provide a clearer signal and image. It is also used in the automobile, plane, and spacecraft.
Silicon carbide industry transformation
Silicon carbide is mainly used in refractory industry, steel industry, and abrasives, with low added value.
At present, “Made in China 2025” and the “13th Five-Year Plan” both clearly set the silicon carbide industry as a key support industry. The State Grid Corporation of China, CRRC, BYD AUTO, and Huawei will increase their investment in silicon carbide. Silicon carbide will be in the ascendant in smart grid, rail traffic, electric automobile, cellphone, etc.
The key to the development of the silicon carbide industry is to transform to deep-processing, high-value-added silicon carbide products in the future.