The Study Of Preparation Technology And Frictional Wear Property Of Copper Matrix Composites Pantograph Slider

Common pantograph slider prepared by powder metallurgy technology usually causes serious abrasion of the conducting wire. Carbon slider is prone to arouse accidents for its high electrical resistivity and low strength. And immersed metal carbon slider need complicated producing process which leads to high cost. To solve these problems, a new kind of preparation technology--hot compressions and consolidation technique was developed, and a copper matrix composite material slider with lower attrition rate and excellent heat-resisting ability was fabricated. In term of the slider material, copper powder was used as conduction phase, graphite powder was used as self-lubricating phase and resin was used as bonding agent. By resin modification of the resin, heat resisting and frictional wear properties of the slider was obviously improved.In this thesis, the chemical constitution of the pantograph slider and the preparation process was explored and optimized. After that, according to the component ratio, the copper matrix composite material was prepared and YM was modified with PBMI subsequently. The frictional and wear properties of the slider were examined by MM-1000 and MM-2000 frictional wear testing machine, thermostability of the resin was analyzed by DTA/TG, and the microstructure of the samples and the morphologies of the friction surface were observed by metallographic microscope and SEM, respectively.The experimental results show that basing on the heat resisting modification of the bonding agent, the attrition rate, friction coefficient and electrical resistivity of the slider were obviously reduced. The optimized composition of the slider material include: electrolytic copper powder 77mass%, graphite 11mass%,NBR1mass%,YM 3mass%,PBMI 7mass%,balance 1mass% . Before modification of the resin, the attrition rate of the material was 7.9×10-8mg/mm3, but after modification, the attrition rate was reduced to 2.6×10-8mg/mm3.The temperature of the exothermic peak in the curve was 550℃before modification, but after modification, the counterpart was up to 675℃. The electrical resistivity of the sample was reduced from 4.83~10.27μ?·m to 2.01-5.54μ?·m after modification. And the friction coefficient of the slider was reduced from 0.18 to 0.10 by modification of the resin. The experimental results show that PBMI resin can not only improve the adhesivity of the composite material, but also exhibit self-lubricating effect on the friction surface during wearing process. And the abrasion mechanisms of the composite material are mainly adhesion abrasion and abrasive grain abrasion.