Time:2023.08.29Browse:1
(1) Carbon based materials: Most carbon based materials use asphalt, but in order to control the filling rate, tar or asphalt is often mixed with low carbonization rate and low viscosity carbon based materials such as tar and creosote. They are carbonized through heat treatment after impregnation, so the residual material entering the pores is only carbon. The carbon process is currently a standard carbon process aimed at improving density, strength, conductivity, thermal conductivity, corrosion resistance, and wear resistance. It has become the most common treatment method for general carbon materials, especially in the production process of fine structured graphite and UHP electrodes for electric furnace steelmaking. It is an indispensable process. In order to achieve the same goal, there are also cases of impregnating synthetic resin and then roasting and carbonization. The carbonization of synthetic resin generally generates hard carbon, which is characterized by greatly increasing hardness and thus improving wear resistance. In addition, compared to asphalt impregnating agents, its reduction effect on air permeability is more significant.
(2) Synthetic resin: Usually, the initial condensate or monomer is impregnated into the product matrix. After impregnation, the impregnating agent completes the condensation effect in the pores through heat treatment or curing agent. The purpose of impregnation is not only to prevent air permeability, but also to improve corrosion resistance, wear resistance, and strength.
(3) Oil: Most oils can use dry oils such as linseed oil and tung oil. Oily substances generally have hydrophobicity, and they are often used to prevent solution penetration (such as conductive rods for electrolytic plates, collector slides, etc.). Sometimes non greasy substances such as paraffin are also used for the same purpose.
(4) Metal: Mainly used are alloys with lower melting points such as Babbitt alloy, as well as metals such as copper and aluminum. The purpose of impregnation is mainly to prevent air permeability, improve strength and hardness, increase conductive capacity, and improve wear resistance. It is mostly used for electrical components such as trolleybus sliders, electrical contacts, and brushes. According to the different usage conditions of graphite materials, the metals and alloys used for impregnation mainly include lead, copper, zinc, silver, and alloys such as tin, antimony, and aluminum.
(5) Inorganic compounds and other impregnating agents: Inorganic compounds are mainly used in the form of aqueous solutions, sometimes also in the form of suspensions. Their main applications include phosphate or alumina impregnation aimed at improving oxidation resistance, iron or molybdenum salt impregnation aimed at enhancing the mercury dissolving ability of mercury based electrolysis of potassium chloride, metal halide impregnation aimed at preventing abnormal wear of aviation brushes, and so on. There are also various lubricants used for impregnation, with the main purpose of reducing brush friction to achieve vibration reduction and reduce power consumption and wear. This impregnation method can greatly improve the effectiveness of the brush in vacuum use.