| Carbon fiber reinforced friction material is one of the components which is reinforced by carbon fiber,and it's widely used in many machines and instruments such as plane,car,motorcycle and high speed train for transmission,decelerating and braking.Carbon fiber reinforced friction material has good mechanical properties,excellent heat-resistance property,low mass,small expansion coefficient and good wear resistance,and it is always the focus of study.In this paper,matrixes were boron modified phenolic resin and ordinary phenolic resin from three different fcttories.Carbon fiber?CF?,ceramic fiber and aramid fiber were used as reinforced fibers.Silicon carbide?SiC?,calcium carbonate?CaCO3?,graphite,SiO2 were added as fillers.All reinforced fibers and fillers were treated by coupling agent KH550,and different types carbon fiber reinforced resin matrix friction materials were made by hot compression molding process.The density of the frictional materials were tested by electronic densimeter,the hardness of the frictional materials were tested by the XHR-150 Rockwell hardness tester,the compression strength of the frictional materials were tested by the CSS-44100 electronic universal testing machine and the impact strength of the frictional materials were tested by the XJJ-5 charpy impact tester.The wear properties of the frictional materials were tested by M-2000A friction machine.The heat resistant properties of the frictional materials were tested by PCY-D thermal expansion instrument and STA449 analyser.The wear surface was observed by SMZ800 stereo microscope and the wear mechanism was analyzed.The results were as followes:?1?Compared and analysised the effects of boron modified phenolic resin and ordinary phenolic resin from three different factories on friction materials.The results showed that phenolic resin from different factories had an obvious effect on the physical properties,mechanical properties,friction and wear properties and thermal properties of friction materials.Boron modified phenolic resin?FB?from each factory had a better performance in mechanical properties,friction and wear properties and thermal properties than ordinary phenolic resin.Friction composites with boron modified phenolic resin of C factory have the highest hardness,compression strength and impact strength,which are 93.42HRL?118.6MPa?3.46 KJ/m2.The friction coefficient of the friction materials with boron modified phenolic resin from C factory is stable,which is 0.65,and the wear is also the least.Friction composites with boron modified phenolic resin of C factory have stable thermal expansion properties,whose expansion coefficient is 11.689×10-6/?,and it is 38.60 percent lesser than the expansion coefficient of friction composites with ordinary phenolic resin of the same factory.?2?Compared and analysised the effects of different ratio of carbon fiber and CaCO3 powder?2%/21%,4%/19%,6%/17%,8%/15%and 10%/13%?on friction material.The results showed that with the increasing of carbon fiber content,the density of friction material decreased gradually,and when the content of carbon fiber is 2%,the friction material has the largest density,which is 1.733g/cm3,when the content of carbon fiber is 10%,the friction material has the smallest density,which is 1.599g/cm3.With the increasing of the content of carbon fiber,the hardness of the friction material increased first and then decreased.When the carbon fiber content is 8%,the friction material has the largest hardness,which is 79.46HRL,when the carbon fiber content is 10%,the friction material has the smallest hardness,which is 58.93HRL.The compression strength and impact strength of the friction materials with different carbon fiber content increased first and then decreased.When the content of carbon fiber is 6%,the friction material has the highest compression strength and impact strength,which is 111 MPa and 3.87KJ/in2.With the increasing of the carbon fiber content,the friction coefficient of the friction material had a little change,but the wear rate decreased first and then increased.When the content of the carbon fiber is 6%,the friction coefficient of the friction material is the highest and stable,and the wear rate of it is 0.0087g under 200N.Before 100?,the thermal expansion coefficient of the composites have a little different.With the increasing of the content of carbon fiber,the thermal expansion coefficient become lower and lower after 100?.The thermal expansion coefficient of B,is 5.089×10-6 and 7.663×10-6 of B1 at 200?.When the content of carbon fiber is 10%,the initial decomposition temperature and redidual mass at 700? were the highest,which are 390? and 75.6%.?3?Compared and analysised the effects of treatment order of coupling agent?KH550?on performance of friction material.The results showed that when the coupling agent just treated the filter,the friction material has the largest density,which is 1.699g/cm3,on the other time,the friction material has the smallest density 1.653 g/cm3 without the treatment of coupling agent.With the different treatment order of the coupling agent,the hardness,compression strength and impact strength changed a lot.When the coupling agent just treated the filter,the friction composites have the highest hardness,compression strength and impact strength,which is 99HRL,146MPa and 3.926KJ/m,and its friction coefficient is stable?0.498-0.481?with the increasing of the load,and the fluctuation range is 0.017.The total wear rate of the four composites is 3.48×10-2,2.56×10-2,3.15×10-2 and 3.37×10-2g under the load from 100N to 200N.The friction material which the coupling agent treat the filter first had better friction property,and the composite also had better thermal expansion property.The thermal expansion coefficient of C2 and Cl is 5.844×10-6/? and 8.711×10-6/? at 200?,the thermal expansion coefficient of C2 is 32.91%than Cl,and 14.45%than C3,25.53%than C4.C2 also has the best thermal resistant property,its initial decomposition temperature is 362.5?,and its redidual mass is 75%at 700?.?4?Compared and analysised the effects of resin content on performance of friction material.The results showed that when the content of the resin is 10%,the friction composite has the largest density,which is 1.723 g/cm3,when the content of the resin is 30%,the friction composite has the smallest density,which is 1.633 g/cm3.With the changing of resin content,the hardness,compression strength and impact strength have a little change,when the content of the resin is 25%,the friction material has the highest hardness,compression strength and impact strength,which are 90.05HRL,146.9MPa,4.028KJ/m2.When the content of resin is 20%,the resin can bond other component tightly,and the friction coefficient of the composite is just 0.504 under the load of 200N.The composites have stable friction coefficient when the content of the resin is 20%and 25%.The thermal expansion coefficient of the five composites is 9.772×10-6/?,10.021 ×10-6/?.18.622×10-6/?,23.473×10-6/?,22.168×10-6/?.When the content of resin is 10%,the friction material has better thermal resistant property,its initial decomposition temperature is 378.5?,and its redidual mass is 81.7%at 700?.When the content of the resin ranges from 15%-25%,the composites have close thermal resistant property,their initial decomposition temperature is 362.5 ?,and its redidual mass is 76.0%at 700?.When the content of resin is 30%,the initial decomposition temperature of the material is 350.5 ?,and its redidual mass is 69.0%at 700 ?. |
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