At least 70 species of silicon carbide crystal type. Alpha silicon carbide is one of the most common allomorph, formed under the high temperature higher than 2000 ° C, has a hexagonal system crystal structure (wurtzite). Beta - silicon carbide, cubic crystal system structure, similar to diamond, in less than 2000 ° C, structure as shown in page attached figure. While on the application of heterogeneous catalyst supporter, because of its higher than alpha type of unit surface area and compelling, but until today, the application of this type is not yet commercially.
Because of its the sublimation of the proportion of 3.2 and high temperature (about 2700 ° C), silicon carbide is suitable for objects as the raw material of bearing or high temperature furnace. Under the pressure of any has been able to achieve, it won't melt, and has a fairly low chemical activity. Because of its high heat conductivity, high breakdown electric field strength and the maximum current density, on the application of high power semiconductor device, a lot of people try to use it to replace silicon [1]. In addition, it has to do with microwave radiation has a strong coupling effect, and all of its high sublimation point, make its practical application in heating of metal.
Pure silicon carbide is colorless, and industrial production of brown to black, because of the impurity content of iron. Crystal rainbow shine because its surface protective layer of silicon dioxide.
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