Effects Of Antifriction Filler On Friction Performance Of Multi-fibers Reinforced Friction Materials

With development of modern automotive industry and the enhancement of conscious on environment protection, the performance of the friction materials was required higher because the friction material in an automotive brake system plays a key role for effective and safe bake performance. Because the asbestos is carcinogenic, scholars all over the world started to research on the non-asbestos friction materials and make a great progress. But compared to foreign country, there is some distance. As China's entrance in WTO, friction materials have to face with rigorous challenge and must accelerate the step on develop automotive friction materials especially on high performance friction material.Based on consulting and analyzing lots of internal and overseas documents about friction materials, we have chosen three kinds of antifriction fillers(graphite,antimony trisulfide,coke) to prepare multi-fiber reinforced friction materials.Analyzing the influence of antifriction fillers on the frictional property, tests results showed that graphite and coke in the intermediate and low temperature range can stabilize the friction coefficient, antimony trisulfide can play at a high temperature stable friction coefficient.Designing the formula by orthogonal test and making range analysis and formula optimization based on the constant speed test results. The formula optimization from this study are summarized as follows:Kevlar pulp 3%, glass fiber12%, grammite 12%, potassium titanate 10%, phenolic resin 10%, graphite 6%, antimony sulphuret 4%, coke 6%, the other 37%. Comparation tests results showed that multi-fiber reinforced friction material with a relatively suitable friction coefficient, sufficient mechanical performance, excellent fade resistance and recovery, low wear ratio in high temperature range as well as expanding the scope of the high temperature brake condition, could meet the need of the property of heavy-duty vehicles brake.The surface morphology of the resulted friction material obtained at different temperatures were analyzed by Scanning Electron Microscope (SEM). Test result shows that adding antifriction fillers makes the friction material formed a layer of dense and stable friction layer in the low temperature. As the temperature increases, the friction surface gradually becomes rough. In the high temperature due to join the antimony trisulfide, antimony trisulfide is oxidized at high temperature oxidation of antimony, which enhance the friction coefficient of friction. Friction coefficient decrease in the course of temperature increasing. The two roles complement each other reduce the thermal decline of friction material at high temperature. Overall, in low temperature rang, the wear mechanism of friction material was grain abrasion and in high temperature range, it was thermal abrasion due to resins decomposition, accompany with adhesion abrasion and fatigue abrasion.Experiment test result shows that formula material with a relatively suitable friction coefficient, good coefficient, good fade resistance and recovery as well as low wear ratio can meet the need of the break property of the Automotive. This kind of brake material formula can be achieved for heavy automobile.