Braking system is one of the key components of a car, a […]
Braking system is one of the key components of a car, and the comprehensive performance of brake pads directly affects the stability and reliability of the braking system. Higher and higher requirements of the car, the corresponding brake friction materials and structures also made more stringent requirements. At present, none of the friction materials that have been used domestically has been able to comprehensively meet the new requirements.
As a result, some racing cars and imported cars mainly rely on imports to maintain their position. This situation has severely restricted the braking performance of automobiles and even the high-speed development of. Therefore, research and development as soon as possible a new type of friction material has become a priority for the friction material industry. Due to the noise, vibration, wear rate and short service life of semi-metallic friction materials and non-asbestos friction material brake pads used in automobile brake systems, alternative carbon / carbon composite friction materials are excellent in performance, the higher cost, usually only used on the plane. The ceramic material with a small proportion, high melting point, hardness, chemical stability and good corrosion resistance, etc., has been widely used in the friction material.
Therefore, the development of friction properties and stability, low wear rate, long life, no noise and vibration of the new ceramic friction material has now become a hot area of friction materials.
Traditional brake pad material is made of asbestos fibers filled with phenolic resin, with asbestos made from silicate minerals and containing a certain amount of water of crystallization in its composition. Hyundai speed increase, so that the braking surface temperature as high as 300 ~ 500 ℃. Asbestos friction material has poor thermal conductivity and heat resistance, will lose crystal water at about 400 ℃, crystal water completely lost at 550 ℃, has basically lost the enhancement effect. Asbestos dehydration will cause friction instability, the working layer of material deterioration, increased wear and tear, there was a clear "hot recession" phenomenon. Coupled with asbestos in the processing, the use of its dust has carcinogenic effects, so asbestos-based brake pads have been banned in Western industrial countries, China has also restricted the use of such materials. Obviously asbestos organic friction material has not adapted to the needs of the automotive industry and the development of modern society, will gradually be replaced by new materials.