Graphite cluster/copper-based powder metallurgy composite for pantograph slider with well-behaved mechanical and wear performance

摘要

Copper based composites with high graphite contents for pantograph sliders have been manufactured via an inexpensive powder metallurgy method. Large size cluster graphite is added into the matrix as solid lubricant to optimize the mechanical and wear performance of the composites. The mechanical performance and microstructure of graphite cluster/copper-based (GC/Cu) composites are investigated. The highest graphite content in GC/Cu composites can reach up to 5 wt%. The graphite cluster/copper-based composites show an outstanding mechanical performance, in which the impact toughness can reach 4.8 J/cm(2) with 5 wt% graphite cluster. The matrix is constituted with single alpha-phase Cu10Sn3 with second phase particles CuNi2Sn. Moreover, friction and wear behavior with or without electric currency have been explored systematically, which indicates that the friction coefficient with 5 wt% graphite composites reached a minimum of 0.184 at a load of 25 N. It also exhibits the excellent friction performance under the effect of electric current. The smallest wear rate of 4.2x10(-3) mg/m occurs in the sample with 2 wt% graphite at 30 A. Meanwhile, the interaction between pantographs and contact wire has been investigated based on elemental analysis and surface morphology. Oxidation and material transfer is found on the worn surface. (C) 2018 Elsevier B.V. All rights reserved.