Silicon carbide is virtually impossible to find naturally in nature and is reported to exist only in meteorites.It is reported that silicon carbide can only be found in meteorites. Silicon carbide was synthesized in the United States in 1891, when the mineral was first synthesized on an industrial scale.In 1891, the United States was the first country to synthesize the mineral on an industrial scale. Silicon carbide has a high degree of hardness and has been used for more than 100 years as the main raw material for abrasives.
For more than 100 years, silicon carbide has been widely used as the main raw material for abrasives. The crystalline structure of silicon carbide, which is similar to that of diamond, determines its high hardness.The crystallographic structure of silicon carbide is similar to that of diamond, which determines its high hardness and strength. In addition, silicon carbide ceramic has semi-conductivity, high thermal conductivity,In addition, silicon carbide ceramic has excellent properties such as semi-conductivity, high thermal conductivity, good creep resistance at high temperatures, and very good oxidation and corrosion resistance. These properties make silicon carbide as high-temperature structural materials which are widely used in heat-resistant, wear-resistant, corrosion-resistant, and other severe chemical environments.Structural components are applied in other harsh chemical environments, such as ceramic engine tappets, ceramic guide wheels, sealing rings, sputtering targets and so on.
The relative molecular weight of silicon carbide is 40.09, of which 70.04% is silicon and 29.96% is carbon, and the true density is 3.21g/cm3. silicon carbide ceramic does not melt at low temperatures, but when the temperature is higher than 2760℃, SiC starts to decompose into silicon vapor and carbon. In fact, SiC from 2200 ℃ -2300 ℃ decomposition, to 2700 ℃ above has been significantly decomposed. In addition, silicon carbide has a small coefficient of thermal expansion and high thermal conductivity. SiC in the reducing atmosphere or neutral medium, until 2200 ℃ high temperature is still very stable. In oxidizing atmosphere, it can be oxidized at high temperature. The oxidation resistance of SiC is still very good up to 1550°C. In fact, SiC particles at 1140 ℃ or more, especially in 1300 ℃ ~ 1500 ℃ has been significantly oxidized, but at this time the generation of SiO2 with the oxidation temperature gradually converted to dense square quartz covered in SiC surface, forming a layer of protective film, preventing the further oxidation of oxygen. Protective film, hindering the further diffusion of oxygen, slowing down the rate of oxidation, so the antioxidant capacity is strengthened.? silicon carbide ceramic which is produced in industrially has yellow or yellowish color due to the presence of free carbon, silicon, iron and other impurities. However, due to the presence of free carbon, silicon, iron and other impurities in the industrially produced silicon carbide, the products are available in different colors such as yellow, black, dark green, light green and so on.