We all know that silicon carbide is widely used in modern daily life, industrial manufacturing, and high-tech products such as chips, military, aviation, etc. Although black silicon carbide and green silicon carbide are both types of silicon carbide. But their uses and cost performance are different.
Black silicon carbide is made of quartz sand, petroleum coke and high-quality silica as the main raw materials, and is smelted at high temperature in a resistance furnace. Its hardness is between brown aluminum oxide and diamond, its mechanical strength is higher than that of brown aluminum oxide, it is brittle and sharp, and it is cheaper than green silicon carbide.
The production method of green silicon carbide is the same as that of black silicon carbide, but the purity of the raw materials used is higher. It is also formed at a high temperature of about 2200°C in a resistance furnace. It is green, translucent, and hexagonal. Its silicon carbide content is higher than that of black silicon carbide. Its physical properties are similar to those of black silicon carbide, but its performance is slightly more brittle than that of black, and it also has good thermal conductivity and semiconductor properties. Its hardness is between that of brown aluminum oxide and diamond, its mechanical strength is higher than that of brown aluminum oxide, and it is more expensive than black silicon carbide.
Application and characteristics of silicon carbide:
Both types of silicon carbide belong to α-SiC.
① Black silicon carbide contains about 95% SiC, and its toughness is higher than that of green silicon carbide. It is mostly used to process materials with low tensile strength, such as glass, ceramics, stone, refractory materials, cast iron and non-ferrous metals.
② Green silicon carbide contains more than about 97% SiC and has good self-sharpening properties. It is mostly used to process cemented carbide, titanium alloy and optical glass. It is also used for honing cylinder liners and fine grinding of high-speed steel tools. In addition, there is cubic silicon carbide, which is a yellow-green crystal made by a special process. The grinding tools used to make it are suitable for superfinishing of bearings, and can make the surface roughness from Ra32~0.16 microns to Ra0.04~0.02 microns in one time.
