Effect Of Al On Friction And Wear Properties Of Cu-based Friction Materials

Copper-based powder metallurgy material is used widely for making brake of high speed train because of its high friction coefficient and good wear resistance.The material is made of Multiple-component. Material properties is regulated by adding different elements.This paper is prepared by powder metallurgy for Cu-Al based materials which is made of copper, aluminum, iron, graphite and SiO2.Making constant speed and simulation of inertial test by friction tester. And making the analysis the change of friction and wear properties for diffenent content of Al under different pressure,different order,dry or wet condition and friction speed.The results show.Under constant speed friction,when the content of Al is little,friction coefficient and wear rate under dry and wet conditions change largely followed friction speed at low speed.When the content of Al is 12%, friction performance become stable,this is because the hardness of material increases followed adding content of Al.,the extent of deformation dropped, when the content exceeds 12%, friction coefficient and wear rate changed little,This is mainly because solubility of Al in Cu is limited.When the pressure changed,the content of Al is lower,the wear rate in high speed is much high,but when the content of Al is high,friction coefficient dropped and fluctuation severely followed adding friction pressure.Wear rate is high. When the content of Al is up to 12%,friction coefficient and wear rate is not sensitive for friction pressure.and when the speed is above to 1500r/min,friction coefficient adds slightly at high pressure and wear rate dropped apparently.When the friction order is different,the material which content of Al is 12% whose friction coefficient keeps stable.Above the content, when the friction order is low to high, the friction coefficient of staying in the middle of the friction is lower than not staying.And the friction coefficient which order is from high to low is higher than that that order is from low to high.This is related to surface state before friction.The wear of low to high is bigger than high to low.Under inertia friction for different contents of Al under friction conditons, friction coefficient of material which content of Al dropped or fluctuated appearently at the beginning or ending time.the friction coefficient is little lower when the Al content is little higher.Friction coefficient which Al content is 12% keeps stable.Compare two different friction mode,when the friction condition is different,friction performance which content is 12% is better.and when the content is lower than it,the friction coefficient is little lower at high speed,and when the content is higher than it,the friction coefficient in all friction is little and fluctuated appearently,the performance is poor.