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Effect of graphite and BN addition on wear performance of copper-based friction material for vehicle clutches |
DAI Shi-xun1,ZHANG Zhu-lin2 |
1 Department of Automotive Engineering, Shandong Labor Vocational and Technical College, Ji’nan 250000, China,2 Department of Automotive Engineering, Shandong Jiao Tong University, Ji’nan 250000, China) |
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Abstract The wear performance of copper-based friction materials for vehicle clutches were studied when graphite and BN were used as lubrication components, and the effects of braking pressure, braking speed and temperature on the friction properties were analyzed. The results show that the wear rate of copper-based friction plate decreases with the increase of graphite content, and the friction coefficient increases with the increase of BN content. The best friction performance is achieved by adding 3% graphite and 2% BN (both mass percent). When the braking speed is 1 000 r/min, the friction factor and wear rate of the samples increase with the temperature rising. When graphite content increases and BN content decreases, the fluctuation range of friction coefficient of the sample also increases. After the friction test, more black massive graphite is formed in C1 sample, and the surface layer is also covered with graphite lubrication layer. BN film has obvious small block distribution characteristics. Its stability is lower than that of continuous large block graphite lubrication layer. BN film is easy to be destroyed and fall off during friction, causing matrix wear and a significant increase in wear rate. The comprehensive application of BN and graphite can achieve better lubricating effect than two single materials, thus obtaining good wear resistance at both room temperature and high temperature.
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Received: 27 December 2018
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