|
The friction material is composed of a friction clutch brake key materials. The working principle of the friction clutch and brake friction pair relative movement, frictional resistance generated in the contact between the surface to adjust the relative movement speed or stop the movement, so as to achieve the purpose of the transmission torque and clutch. Mainly used in aircraft, tanks, trains, ships and machinery brake, transmission torque and overload insurance device. Friction material should have a good performance the traditional friction material is difficult to meet the specific requirements of the use, and the only powder metallurgy friction material due to its own characteristics, such as a high coefficient of friction, high wear resistance, corrosion resistance, thermal conductivity good, and use a load higher, to meet the requirements of the relevant parts, and thus access to a wide range of applications. This thesis, superior performance, and overall well-matched friction material by powder metallurgy method. The orthogonal test test Fe, Sn, SiO2 and graphite four auxiliary element composition optimization; proven friction material hardness, volume, the amount of wear and coefficient of friction were optimal sample ratio and draw each component of the friction material indicators; followed by the calculation of the index test results and judgment, in order to fully assess the experimental effects, the overall balance method to analyze the test results of the multi-index, and arrive at a final the optimal combination; Finally, select the the final optimal combination and get the optimal combination of hardness index, the amount of volume wear indicators, the coefficient of friction indicators, these four optimal combination of materials repeatability of experiments to compare. The experimental results show that the optimal material formulations under the specific conditions for the 4Sn8Fe10C8SiO2 obtained after the analysis of the overall balance of the various experimental indicators. In the crystal phase under the microscope to observe the microstructure of the sintered body, and found that the Sn in the sintered body can be sufficiently diffused, graphite uniformly interspersed among the copper matrix, to improve the strength of the sintered body composition changes before and after sintering, XRD cf compacts found CuSn3 new phase is generated in the sintered body, these new Xiangde generated, the strength and friction and wear properties of the friction material can be further improved; ball disc wear tests showed that each of the samples under test conditions at room temperature, the friction coefficient are relatively stable , scanning electron microscopy morphology of the wear scar, each group of specimens are reflected in the slight wear characteristics. In the process, the thesis repeatedly pressed density compacts found to enhance the pressing times, without further improving the pressing pressure, and the hardness of the compacts can be improved to a certain extent, but has little effect on the density of the green compacts, also found that as long as the strict control of good pressing process, for the higher carbon content of the mixed powder, due to the poor adhesion of the powder, several times with repression can suppress waste without incurring waste of raw materials to improve the strength of the green compacts.
|