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Compressibility of automotive brake friction materials and friction properties of

Author: LiuZuoZuo
Tutor: XiongXiang；LiuBoWei
School: Central South University
Course: Materials Science
Keywords: Nitrile rubber / phenolic resin blends Steel fiber Six whiskers Compressibility Friction and wear properties
CLC: U465
Type: Master's thesis
Year: 2009
Downloads: 98
Quote: 0
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Abstract

Safety, comfort and environmental protection is a modern automotive brake friction material gives the three performance requirements. Friction and wear performance evaluation of the friction material has always been the most important performance parameters of safety; while the compressibility is recently proposed a measure of friction material comfort, an important performance indicators. In this paper, a mature semi-metallic friction material formulations, based on research from the perspective of formula system by testing the friction coefficient, wear rate, cold and hot compression deformation, porosity, thermal expansion and the use of scanning electron microscopy detection means systematically studied nitrile rubber / phenolic resin blend ratio of binder content, steel fiber content and potassium titanate whisker content on the compressibility and friction and wear properties. The main results of this experiment are described below: 1, nitrile rubber and phenolic resin blend ratio and the six whiskers content increases can significantly improve the compressibility of the material at room temperature, for each 1% increase in nitrile rubber and six whiskers and a thickness of 17.0mm compression deformation of the specimen were increased about 10.4μm and 2.5μm; binder and steel fiber content on the room temperature compressibility effects is not obvious. 2, nitrile rubber and phenolic resin composition ratio (≤ 1), the binder content and the content of potassium titanate whiskers can significantly change the material increased under high compressibility. Each 1% increase in nitrile rubber and six whiskers and a thickness of 17.0mm specimen deformation decreased approximately 17.0μm and 4.9μm; every 1% increase in the binder material deformation is about increase 16.6μm; steel fiber content on the impact of high compressibility obvious. 3, with the nitrile rubber and phenolic resin blend ratio increases, the material at low temperatures (≤ 200 ℃) of the friction factor increases first and then decreases friction coefficient under high temperature thermal recession decreases and then increases; over the entire temperature range , reduce the wear after the first increase. When nitrile rubber and phenolic resin blend ratio of 1/5 to 1/2, the friction and wear properties of materials best. 4 to nitrile rubber and phenolic resin blend ratio of 1/2 blends as a binder, with the binder content increases, the friction factor increased first and then decreased gradually; wear decreased first then increased; when the binder content ≤ 16%, the thermal fading are small, as the binder content increases to 20%, the material severe heat fading; formulations in the group, the binder The optimum content of 12%. 5, with the steel fiber content increases, thermal recession was first decreased and then increased, the wear rate increases; Among them, steel fiber content of 10% -15% of the minimum heat fading, the friction factor in the whole experiment stable temperature range. 6, with the potassium titanate whisker content increases, the thermal recession and decreased wear of the lead, when potassium titanate whisker content to 16%, the heat fading and wear rate has increased. Not added potassium titanate whisker materials, adding an appropriate amount (8% ~ 12%) of the potassium titanate whiskers can effectively improve the friction properties of high friction material.

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