| Friction material is one of the most important functional components of mechanical vehicles and equipments,and it’s widely used as cluth,brake linings and brake pads in motorcycle,car,train and plane.Its main founction is transmission,deceleration and braking.And phenolic resin based friction material has been the focus of the study of friction materials because of its advantages of controllable performance,wide application and simple production technology.Phenolic resin based friction material mainly consists of resin base(also called binder),reinforcing agent,lubricant,abrasive and some other fillers.The main founction of phenolic resin base is bonding fillers.transmitting and uniforming load.And it also has vital effect on friction and wear properties,impact resistance properties and heat resistance properties of friction material.Thus,good performance of phenolic resin based friction material can only be achieved by the selecton of appropriate resin.The strength,friction and wear properties of friction material are closely related with the type and content of reinforcing agent.The friction confficient and wear resistance of friction material are mainly devoted by abrasive.Then a suitable type and content of reinforcing agent and abrasive are the key factors to improve the performance of friction material.In this paper,filled with carbon powder,graphite particles,nitrile butadiene rubber(NBR)and kinds of abrasives,different kinds of friction material were prepared with different modified phenolic resin base.The friction material was formed by die pressing in the temperature of 180℃ and in the load of 30MPa.The density of the friction material was tested by DH-300 electronic densimeter,the hardness of the friction material was tested by XHR-150 plastic Rockwell hardness tester,the compression strength of the friction material was tested by CSS-44100 electronic universal material testing machine,and the friction and wear properties of the friction material was tested by M-2000A friction and wear testing machine in the loads of 100N,150N and 200N.The thermal stability of the friction material was analyzed by STA 449 analyser.The results were as followes:(1)Compared and analysised the effects of different modified phenolic resin on friction material,including boron modified phenoloc resin,epoxy resin modified phenolic resin,cashew oil modified phenolic resin,polymer modified phenolic resin and NBR modified phenolic resin.The results showed that the compression strength and impact strength of cashew oil modified phenolic resin based friction material were the most stable,which are 110.6MPa and 2.094kJ/m2.NBR modified phenolic resin based friction material has the highest compression strength and impact strength.witch are 113.4MPa and 2.880kJ/m2,and the initial decomposition temperature,mass decomposition temperature and redidual mass of 750℃ were the best and highest,which are 414.5℃ 544.5℃ and 91.38%.The friction confficient was the highest and the wear lost was the least of boron modified phenoloc resin based friction material,which are 0.166 and 1.23mg.(2)Compared and analysised the effects of different ratio of cashew oil modified phenolic resin and carbon powder(20%/65%,25%/60%.30%/55%and 35%/50%)on friction material.The results showed that with the increasing of carbon content and decreasing of resin,the density of friction material decreased,the hardness,compressive strength and impact strength increased first and then decreased.When the ratio of phenolic resin and carbon was 30%/55%,the mechanical properities were the best,compressive strength and impact strength are 178.8MPa and 3.436 kJ/m2.When the ratio of phenolic resin and carbon was 25%/60%,the friction confficient and mass decomposition temperature were the highest,which are 0.178 and 441.3℃.When the ratio of phenolic resin and carbon was 20%/65%,the initial decomposition temperature and redidual mass of 750℃ were the highest,which are 391.9℃ and 88.6%.(3)Compared and analysised the effects of carbon particle size(300 mesh,500 mesh and 800 mesh)on performance of friction material.The results showed that with the decreasing of carbon particle size,the hardness,compression strength and impact strength decreased.The friction material with 300 mesh carbon particle has the highest hardness,compression strength and impact strength,witch are 109HRL、178.8MPa and 3.436 kJ/m2.Under the loads of 100N and 150N,the friction confficient decreased with the carbon particle size decreasing.Under the load of 200N,the friction material with 500 mesh carbon particle has the least friction confficient,which is 0.166,and the friction material with 800 mesh carbon particle has the highest friction confficient,which is 0.183.The friction confficient of the friction material with 800 mesh carbon particle was more stable under lower pressure,and that of the friction material with 300 and 500 mesh carbon particle was more stable under higher pressure.(4)Compared and analysised the effects of powder and fibrous of SiC,SiO2 and Al2O3 abrasives on friction material.The results showed that the compression strength and impact strength of friction material with fibrous abrasives were higher than that with powder abrasives.The friction material with SiO2 fiber abrasive has the highest compression strength,which is 150.8MPa,and that with SiC fiber abrasive has the highest impact strength,which is 3.652 kJ/m2.Under the same load,with the same state of powder abrasives,the friction material with SiC has the highest friction confficient and that with Al2O3 has the least friction confficient.Under the same load,with the same state of fibrous abrasives,the friction material with SiC has the highest friction confficient and that with SiO2 has the least friction confficient.The friction confficient of friction material with SiO2 fiber abrasive was most stable.that with Al2O3 powder followed,and the fluctuation of that with powder and fibrous SiC was the largest. |
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