Carbon and graphite compounds are used for standard bearings, which have excellent corrosion resistance when working in most liquid environments.

Some liquid containing solid abrasives will hinder the binder or process and affect the use of graphite bearings. Alternative materials in this case, such as:

silicon carbide

Carbon graphite

alumina

Cemented carbide bearings

A cemented bearing is a bearing made from a hard alloy. Tungsten carbide bearing has the characteristics of super high wear resistance and high impact resistance. The surface and inner hole of the cemented carbide bearing can achieve the mirror effect.

Carbon graphite bearing

Carbon graphite is a kind of graphite bearing material with high temperature resistance and certain self lubricating function. Its most significant advantages are high temperature stability and strong chemical corrosion resistance. In the early stage of development of graphite bearing, especially in strong corrosive medium or high temperature environment, carbon graphite has been used as bearing material and has been applied to some extent. With the progress of the powder metallurgy industry and the maturity of the impregnation process, the new impregnated graphite bearing has gradually replaced carbon graphite with its excellent properties.

Although the pure carbon graphite corrosion resistance and high temperature resistance is relatively high, but as bearing materials, flexural strength, compressive strength and its impact performance is poor, this is mainly due to its relatively large porosity (about 10% ~20%), and these are not impregnated filling holes, there is no play the reinforcing effect. But in some special occasions, the working medium is strongly corrosive, or because of the size of the structure, it is impossible to set up the heat shield without shielding the load.

Silicon carbide bearing

Carborundum belongs to ceramics, and most of the general ceramics now refer to ceramics other than carbon. Such ceramics are mainly Si3N4 and SiC, and their hardness is very high. The hardness of the SiO2, whose composition is mainly composed of sediment (HV800~1 000), is higher. Therefore, it has strong adaptability to impurities. The disadvantage is that the impact resistance is poor, but the measures can be taken to a certain extent according to the bearing structure.

Imported silicon carbide has been applied in many fields because of its high hardness, high temperature creep, high wear resistance, corrosion resistance and oxidation resistance. Silicon carbide can be divided into three kinds, such as high pressure sintering, pressure free sintering and reaction sintering, according to the different sintering methods. At present, the pressure free silicon carbide (SIC) has been widely used in shielded motor because of its high wear resistance and low friction coefficient. Under the condition of water lubrication, silicon carbide can produce a film of silicon dioxide and silica gel on the surface to further reduce the friction coefficient. The silicon carbide itself has the function of self lubrication, which is suitable for the material of friction. However, because of the high hardness of silicon carbide, the impact toughness is relatively low, and the fracture toughness of SiC without pressure sintering is only about 3~4MPa. M1/2. It is not suitable for the shock vibration condition, the silicon carbide as bearing material used in motor, in addition to the selection of spraying surface (or welding) of tungsten carbide grinding parts as friction pair, but also for special design in structure, set up special measures should be to force groove, to prevent silicon carbide by the impact have broken. At the same time, when silicon carbide is used as a bearing material to shield motors, the conveying medium must be clean and free of impurities, and requires stable operation and no vibration. Therefore, silicon carbide as a bearing material has greatly improved the friction life of tungsten carbide bearings. However, under the condition of high reliability, especially the shielded motor used for military and nuclear power, there are few uses of silicon carbide as bearing material, and the reliability needs further study.

Alumina bearing

This material is very similar to silicon carbide in abrasion resistance and corrosion resistance. However, it is also easily affected by the temperature adjustment and the impact of the operation of the machine.

For more information: http://www.wococarbide.com/Transaction/en_information.html

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