Introduction To Relevant Knowledge Of Silicon Carbide

Silicon carbide, also known as carborundum, is made by melting quartz sand, petroleum coke (or coal coke), sawdust (salt is required to produce green silicon carbide) and other raw materials in a resistance furnace at high temperature. In silicon carbide, there is also a rare mineral mulberry stone in nature. Silicon carbide is also called carborundum. Among non-oxide high-tech refractory materials such as carbon, nitrogen and boron, silicon carbide is a widely used and economical one, which can be called diamond sand or refractory sand. At present, industrial silicon carbide produced in China is divided into black silicon carbide and green silicon carbide, both of which are hexagonal crystals, with a specific gravity of 3.203.25 and a microhardness of 28403320kg/mm2. Silicon carbide products have special functions such as high temperature resistance, wear resistance, thermal shock resistance, chemical corrosion resistance, radiation resistance, excellent conductivity and thermal conductivity. So silicon carbide is widely used in all sectors of the national economy. In China, green silicon carbide is mainly used as abrasive. Black silicon carbide is used for manufacturing abrasive tools, mainly for cutting and grinding materials with low tensile strength, such as glass, ceramics, stone and refractory materials, and also for grinding cast iron parts and non-ferrous metal materials. Abrasives made of green silicon carbide are mostly used for grinding cemented carbide, titanium alloy and optical glass, and also for honing cylinder liners and precision grinding of high-speed steel tools. Cubic silicon carbide grinding tools are specially used for ultra-precision grinding of miniature bearings. The abrasion resistance of water turbine impeller can be greatly improved by coating silicon carbide powder on the impeller by electroplating. By using mechanical pressure to press cubic SiC200 powder and W28 powder into the cylinder wall of internal combustion engine, the service life of the cylinder can be more than doubled.
Silicon carbide dust may be harmful. Inhaling silicon carbide dust through the respiratory tract can cause cough, expectoration, chest pain, chest tightness, shortness of breath, dyspnea, etc. In addition, the density of the hilus of the lung increases and widens, and the lung texture is distorted and deformed, resulting in symptoms such as mesh of different thickness. Hazard protection: use dust protection articles: dust mask, dust glasses, dust helmet, dust suit, dust shoes, etc. Pay attention to personal hygiene, do not smoke, put an end to taking work clothes contaminated by dust home, take regular physical exercise, strengthen nutrition and strengthen personal physique. Material characteristics of silicon carbide: silicon carbide has stable chemical properties, high thermal conductivity, low thermal expansion coefficient and good wear resistance. It has many other uses besides abrasive. For example, coating silicon carbide powder on the inner wall of turbine impeller or cylinder block through special process can improve its wear resistance and prolong its service life by 12 times. The advanced refractory made by this method has the advantages of thermal shock resistance, small size, light weight, high strength and good energy-saving effect. Low-grade silicon carbide (containing about 85% SiC) is an excellent deoxidizer, which can speed up steelmaking, control chemical composition and improve steel quality. In addition, silicon carbide is also widely used to manufacture silicon carbide rods for electric heating elements.