The Study Of Cell-like Structure Of Friction Materials

With pretty wide usage of friction materials in the automobile brake device, non-asbestos fiber reinforced resin matrix friction material has attracted more and more attention from all walks of life. In light of the phenomenon of the sudden decrease of the friction factor caused by hot recession when the traditional friction materials is in the high resin content, the author has launched a non-asbestos resin-type cells structure of friction materials research with the help of the full set of advanced automotive friction materials testing equipment from Jilin University. During the research, granulation technology, particle coated and the second binder have been tried, with the use of mineral fibers as the strengthened fiber and the bakelite as the first binder. To enhance the efficiency of the vehicle's braking system and to reduce the resin content, a lot of work has been done to optimize the friction material of the brake, which lays a solid theoretical ground for the design of the new brake friction material. Meanwhile, the evolutions of friction materials from simple materials to the coupling of structure with the material and the binder from function elements have been promoted into the coupling of structure with the process elements.With contents of the iron as the tracer, the technology of mixing friction materials has been inspected, which concluded that the best drum mixing speed was 120r/min with stirred knife speed 576r/min and mixing time was 10min.With grain rate and apparent density of the particles as indicators of the quality of the evaluation, the raw materials of the friction materials granulation process has been inspected, which concluded that the best granulation process parameters for the cylinder speed was 120r/min with stirred knife speed 384r/min, granulation time was 10min with water as the best bridge. Of the fiber types and content on the effect of granulation, the study showed the best results come out when the fiber content of sepiolite was 16wt% with the content of phenolic resin 22wt% and the water content was 40%.Research has been done on the granulation of the friction of the friction and wear properties with results that the friction factor of the granulation of the friction increased by 2.05%～19.74% than those of the ordinary method while the wear rate of granulation friction deceased by 36.48%～65.38%.The size classification of granulation has made to the wear properties of friction materials, which concluded that adopting a classification with a mixture of different size particles by the suppression of the friction materials tribological properties was superior to the wear properties of friction materials made from different levels of particles with the same diameter. Specifictly, the friction factor was increased by 6.1%～34.3%; the wear rate was increased by 3.8%～58.3%. The wear properties of friction materials whose particle diameter was 8mm would be the next to the best.Different content of the first binder (phenolic resin) and the second binder have been made on the wear rate of friction materials and on how the second binder works in the friction materials. It was concluded that cell-like structure of friction material performs was better under the same formula, because the smooth change in the friction factor, fewer wear rate (friction factor was changing in the scope of 0.212-0.373, while the wear rate was in the scope of the 0.096-0.792×10-7cm3/N·m) and better performance of the wear properties of the friction materials with a second binder added in it.Research has been done on the surface friction of the cell-like structure of friction material with the help of stereo microscope, which showed that the main mechanism during the course of friction mainly laid in abrasive wear, adhesive wear and fatigue wear. In the process of friction, the second binder has suffered adhesion phenomenon and sulfuration, which made up the shortage of thermal decomposition of matrix binder and the lack of stability of the wear properties of friction materials at high temperatures. With the melting process and sulfuration, the second binder has been absorbed some of the wear debris to fill the pit of the friction surface, which would improve the wear resistance of the friction materials.With the combination, a binder matrix was added to the stability of the friction and wear properties of the friction materials at high temperatures, the second binder has been absorbed some of the wear debris to fill the pit of the friction surface, Crack would help improve the wear resistance of the friction materials, cell-like structure of the friction material made from particles with different sizes (diameter of 1-10mm) was better than those with the same size of particle.