1. Carbon brushes application
Carbon brushes, also known as brushes, are widely used in many electrical devices as a sliding contact. The carbon brush is mainly made of graphite, immersed graphite, metal (including copper, silver) graphite. A carbon brush is a device that transfers energy or signals between a fixed part and a rotating part of an electric motor or generator or other rotating machine. It is generally made of pure carbon plus a coagulant. The outer shape is generally a square and is stuck on a metal bracket. There is a spring to press it on the rotating shaft. When the motor rotates, the electric energy is sent to the coil through the phase converter. Since its main component is carbon, it is called carbon brush, which is easy to wear. The replacement should be maintained regularly and the carbon deposits should be cleaned.
It is a device that transfers energy or signal between the fixed part and the rotating part of an electric motor or generator or other rotating machinery. It is generally made of pure carbon plus coagulant. The outer shape is usually a square, which is stuck on the metal bracket and has a spring inside. Press it on the shaft. For example, after the oil drilling is completed, it needs to be tested. It is necessary to put the instrument from the wellbore, and the signal is sent from the rotating part (the cable drum of the outer steel wire) to the ground instrument through the carbon brush. The carbon brush looks a bit like a rubber strip with a pencil and a wire on the top. The volume is large or small. As a sliding contact, carbon brushes are widely used in many electrical equipment. The material of the product mainly includes electrochemical graphite, immersion grease graphite, metal (including copper, silver) graphite.
The role of the carbon brush is mainly to conduct electricity while rubbing the metal; it is not the same as when the metal is rubbed against the metal; when the metal is rubbed against the metal, the friction may increase; at the same time, the place where the intersection may be sintered; Carbon brushes do not; because carbon and metal are two different elements; most of its uses are used on electric motors; the shapes are varied; squares are round and so on.
2. Graphite product application
1) Traditional use
1. As refractory material: Graphite and its products have the properties of high temperature resistance and high strength. They are mainly used in the metallurgical industry to manufacture graphite crucibles. In steelmaking, graphite is commonly used as a protective agent for steel ingots and the inner liner of metallurgical furnaces.
2. Conductive material: used in the electrical industry as a positive electrode for the manufacture of electrodes, brushes, carbon rods, carbon tubes, mercury positive flow devices, graphite gaskets, telephone parts, coatings for television picture tubes, etc.
3. Wear-resistant lubricants: Graphite is often used as a lubricant in the machine industry. Lubricating oils are often not used under high speed, high temperature and high pressure conditions, while graphite wear resistant materials can work at high sliding speeds of 200~2000 °C without lubricating oil. Many equipments that transport corrosive media are widely used in graphite materials to make piston cups, seals and bearings. They do not need to be lubricated during operation. Graphite milk is also a good lubricant for many metal processing (drawing, drawing).
4. Graphite has good chemical stability. Specially processed graphite, which has the characteristics of corrosion resistance, good thermal conductivity and low permeability, is widely used in the manufacture of heat exchangers, reaction tanks, condensers, combustion towers, absorption towers, coolers, heaters, filters. , pump equipment. Widely used in petrochemical, hydrometallurgy, acid and alkali production, synthetic fiber, paper and other industrial sectors, can save a lot of metal materials.
The type of impervious graphite differs depending on the resin contained and the corrosion resistance varies. For example, the phenolic resin impregnated is acid-resistant, but not alkali-resistant; the decyl alcohol resin is impregnated with both acid and alkali. The heat resistance of different varieties is also different: carbon and graphite can withstand 2000~3000 °C in reducing atmosphere, and oxidize at 350 °C and 400 °C respectively in oxidizing atmosphere; the type of impervious graphite varies with impregnating agent, generally The impregnated by phenolic or decyl alcohol is heat resistant to 180 ° C or less.
5. For casting, sanding, compression molding and pyrometallurgical materials: Because graphite has a small thermal expansion coefficient and can withstand rapid cooling and rapid changes, it can be used as a mold for glassware. After using graphite, ferrous metals can be used to obtain accurate casting dimensions and high surface finish yield. It can be used without processing or a little processing, thus saving a lot of metal. Production of cemented metallurgy and other powder metallurgy processes, usually made of graphite materials for stamping and sintering of porcelain boats. Crystal growth of single crystal silicon, regional refining vessels, bracket fixtures, induction heaters, etc. are all processed from high purity graphite. In addition, graphite can also be used for vacuum smelting of graphite insulation boards and bases, high-temperature resistance furnace tubes, rods, plates, grids and other components.
6.for the atomic energy industry and the national defense industry: graphite has a good neutron moderator for use in atomic reactors, uranium-graphite reactor is a more widely used atomic reactor. The decelerating material in the nuclear reactor as a power source should have a high melting point, stable, and corrosion-resistant properties, and graphite can fully satisfy the above requirements. The purity of graphite used as an atomic reactor is very high, and the impurity content should not exceed tens of PPM. In particular, the boron content should be less than 0.5 PPM. In the defense industry, graphite is also used to make solid fuel rocket nozzles, missile nose cones, parts of space navigation equipment, insulation materials and radiation protection materials.
7. Graphite also prevents boiler fouling. The relevant unit tests have shown that adding a certain amount of graphite powder (about 4 to 5 grams per ton of water) in water can prevent scaling on the boiler surface. In addition, graphite can be coated on metal chimneys, roofs, bridges and pipes to prevent corrosion and rust.
8. Graphite can be used as pencil lead, pigment, and polishing agent. After special processing of graphite, various special materials can be produced for the relevant industrial sectors.
9. Electrode: Why can graphite replace copper as an electrode?
In the 1960s, copper was widely used as an electrode material, with a usage rate of about 90% and graphite of only about 10%. In the 21st century, more and more users began to choose graphite as an electrode material, in Europe, more than 90%. The above electrode material is graphite. Copper, the once dominant electrode material, has almost lost its advantages compared to graphite electrodes. What caused this dramatic change? Of course, there are many advantages of graphite electrodes.
2) Light industrial applications
In addition, graphite is a polishing agent and rust inhibitor for glass and paper in the light industry. It is an indispensable raw material for the manufacture of pencils, inks, black lacquers, inks and synthetic diamonds and diamonds. It is a good energy-saving and environmentally friendly material that the United States has used as a car battery. With the development of modern science and technology and industry, the application field of graphite is still expanding, and it has become an important raw material for new composite materials in the high-tech field.