What is friction coating and what are the commonly used materials

       Friction and lubrication are two diametrically opposed concepts in tribology. Lubrication is to reduce the resistance of movement, and friction is to increase the resistance of movement and even braking. It can be said that without friction braking, there is no automation.



1. Anti-friction lubricating coating material



Generally speaking, the friction coefficient of solid lubricating coating materials is larger than that of lubricating oil and lubricating grease, which consumes more energy to overcome friction, and does not have the cooling effect and suspension effect of oil lubrication, and the cost is also high. Therefore, the coatings made of composite powders that we often use are mostly used in the motion friction of machinery that requires oil-free lubrication, dry friction, boundary lubrication and cannot be maintained. Graphite, nickel-coated molybdenum disulfide, aluminum-silicon-polystyrene grease, etc.



2. Wear-increasing friction coating material



Brakes, clutches, brakes, dampers, etc. of various sports machinery, the lining friction material requires a high friction coefficient, and at the same time has sufficient high temperature strength, can withstand the high temperature generated by high-speed braking, and has good heat conduction It can quickly dissipate a large amount of friction heat generated by braking without burning and wear, and it must be wear-resistant, with less wear on the friction pair and stable braking. Conventional metal-based friction materials (such as cast iron) have good thermal conductivity, but insufficient high temperature resistance, small friction coefficient, and easy to slip; inorganic friction materials (such as asbestos) have large friction resistance, good heat resistance, but poor thermal conductivity. The high heat generated by friction can burn parts, and asbestos is a carcinogen.



The friction resistance composite powder material is made of high hardness, high friction and heat-resistant ceramics, cemented carbide particles and metal powder with good thermal conductivity and high strength through agglomeration and compounding. In order to brake smoothly and reduce wear, a small amount of solid lubricant can also be added. The spray coating of this composite powder has a typical metal-ceramic structure, and has the comprehensive advantages of metal brake materials and non-metal brake materials: the former has good thermal conductivity, and can conduct a large amount of heat generated by friction to avoid local overheating , high strength, good thermal shock resistance, and the latter has the advantages of high hardness, high friction and good heat resistance. This coating does not contain organic compounds and is especially suitable for friction materials in high temperature and non-lubricated applications. Commonly used wear-increasing friction coating materials include copper-based high-strength friction coating materials, cobalt-based high-temperature friction-removing coating materials, and the like.