Sunrise Refractories Analysis on the Properties and Industrial Applications of Silicon Carbide

Silicon carbide is a non-metal carbide composed of silicon and carbon in a covalent bond. Its hardness is second only to diamond and boron carbide. In the refractory industry, silicon carbide is used to produce various silicon carbide bricks, and it can also be used as an additive. Or antioxidants. Zhengzhou Sunrise Refractories will use this article to analyze the properties of silicon carbide and its application in the refractory industry.

 

Silicon carbide for refractories is divided into) high-grade refractory black silicon carbide and secondary refractory black silicon carbide. The SiC content of advanced silicon carbide is exactly the same as that of abrasive silicon carbide. The secondary refractory is black silicon carbide, and the SiC content is greater than 90%. (3) Black silicon carbide, a low-grade refractory, with an SiC content of more than 83%. Silicon carbide for deoxidizer, SiC content is generally required to be greater than 90%. But the carbon industry graphite furnace insulation material silicon carbide content of more than 45% can also be used as a steelmaking deoxidizer. There are two types of silicon carbide for deoxidizer: powder and molding. The powdered deoxidizer black silicon carbide usually has two particle sizes of 4 to 0.5 mm and 0.5 to 0.1 mm.

 

According to different colors, uses and structures, silicon carbide can be divided into different categories. Pure silicon carbide is colorless and transparent crystal. Industrial silicon carbide is colorless, light yellow, light green, dark green or light blue, dark blue, or even black. The abrasive industry divides silicon carbide into black silicon carbide and green silicon carbide according to color and luster. Among them, colorless to dark green are classified as green silicon carbide. Light blue to black are classified as black silicon carbide.

 

The reason for the multicolor of silicon carbide is related to the presence of various impurities. Industrial silicon carbide usually contains about 2% of various impurities, mainly silicon dioxide, silicon, iron, aluminum, calcium, magnesium, carbon and so on. When more carbon is melted in the crystal, the crystal is black. Green silicon carbide is more brittle and black silicon carbide is tougher. The former has a slightly higher grinding capacity than the latter. According to the size, the products are divided into different grades.

 

Silicon carbide products have special properties such as high temperature resistance, abrasion resistance, thermal shock resistance, chemical resistance, radiation resistance, good electrical and thermal conductivity, etc., so they have a wide range of uses in various sectors of the national economy.

In the electrical industry, silicon carbide can be used as a surge arrester valve body, silicon carbon electric heating element, far-infrared generator and so on. In the electronics industry, for example, a large piece of complete silicon carbide single crystal is cultivated by special methods in an industrial silicon carbide furnace or on an industrial furnace, and can be used as a substrate for light-emitting diodes (such as crystal lamps and digital tube lamps). High-purity silicon carbide crystal is a high-quality material for making radiation-resistant high-temperature semiconductors. Silicon carbide is one of the few semiconductor materials with a large forbidden band width (2.86eV) and two conductivity types, P and n.

 

In the aerospace industry, gas filters and combustion chamber nozzles made of silicon carbide have been used in rocket technology. Silicon carbide fiber, which has achieved industrial production, is a new type of high-strength, high-modulus material with excellent heat resistance and oxidation resistance, and has good compatibility with metals and resins. The service temperature can reach 1200 ℃, and the strength retention rate can reach more than 80% under high temperature. It can be used to make heat shielding materials, high temperature resistant conveyor belts, filter cloths to filter high temperature gases or molten metals, and it can also be used in combination with carbon fibers or glass fibers as reinforcing materials for reinforcing metals and ceramics. Low grade silicon carbide can be used as steelmaking deoxidizer and cast iron additive.

 

Silicon carbide production requires high-temperature operation, and measures such as preventing burns and heatstroke and cooling should be paid attention to. In addition, silicon carbide powder is an inert powder with stable chemical properties and high hardness. It is inhaled into the lungs and deposited in the lungs, causing lung diseases. High-concentration powders cause pneumoconiosis, and attention should be paid to dust protection. Silicon carbide is sealed with polyethylene plastic bag and packed with polypropylene woven bag. The net weight of each bag is 25 kg. Store in a cool, ventilated and dry warehouse. Do not co-storage with inorganic acids and alkalis. Prevent rain during transportation. Handle lightly during transportation to prevent package damage.