Study On The Effect Of Water On The Friction And Wear Performance Of The Carbon/metal Contact Pair With Electric Current

In high-speed railways,the carbon/metal sliding conductive pair composed of pantograph strips and catenary wires is the only way for trains to obtain electrical energy.In recent years,on-site working conditions have shown that the pantograph strip wears in a humid environment,resulting in frequent failure of the strip,which may cause pantograph and catenary accidents in severe cases.The deterioration of the current-carrying friction and wear behavior of water on the pantograph-catenary contact pair and the anti-friction effect of water in the field of pure mechanical friction reflect the opposite.At present,the effect and mechanism of water on the friction and wear performance of the carbon/metal contact pair with electric current are still unclear.Therefore,this thesis mainly conducts related research on the friction and wear performance of the water-containing carbon/metal contact pair.Based on the sliding reciprocating current-carrying friction and wear tester,the sliding friction and wear test of carbon materials and metal materials under different water levels was carried out.In order to study the difference of wear performance of pantograph strip in water and dry conditions more comprehensively,the effect of different water levels on the friction and wear of the carbon/metal contact pair under pure mechanical friction was first studied,the variation of surface temperature rise,friction coefficient and wear loss of carbon material were obtained,the influence mechanism of water cooling and lubrication on the above factors was analyzed.Combined with the wear morphology,the wear pattern of carbon material surface under pure mechanical friction is mainly slight mechanical wear with abrasive wear.For carbon/metal contact pair with electric current,the tribological behavior and damage characteristics of carbon materials are affected by electromechanical coupling.In this thesis,the friction and wear performance of pair with different water content were studied from two aspects of electrical contact characteristics and friction and wear characteristics.A comparative analysis of the surface temperature rise of the carbon material under pure mechanical and current-carrying friction,the number of discharges,the total discharge energy,and the change law of contact resistance of the contact pair,combined with the wear surface morphology of the carbon material,analyzed the carbon material caused by different levels of water content.The reason for the difference in contact discharge;the change characteristics of the friction coefficient of the contact pair and the amount of wear of the carbon material are clarified,and the difference in the surface abrasion morphology of the carbon material under different water levels is studied,and the difference in the water-carrying capacity of the carbon material is investigated.The influence mechanism of the current-carrying friction and wear performance of the contact pair indicates that the water intrusion into the contact interface not only changes its lubrication state,but also has an important influence on the conduction mode and path of the current between the contact pair,so that the electromechanical coupling effect occurs during the operation of the contact pair.Significant changes affect the current-carrying efficiency and friction and wear performance of carbon/metal electrical contact pair.The results can provide references for the environmental adaptability research of carbon/metal sliding friction with electric current.