Abstract
The copper matrix composites were prepared by spark plasma sintering (SPS). The current-carrying friction and wear tests were carried out on a self-made HST-100 high-speed current-carrying friction and wear tester, and the effect of the graphite content on the current-carrying friction and wear properties of the composite material was studied. The results show that with an increase in graphite content, the average friction coefficient and wear rate of the two materials decreased significantly, the fluctuation amplitude of the friction coefficient was also significantly reduced, and the average friction coefficient of copper-coated graphite composite with graphite content of 10 wt.% was 0.100; when the graphite content was the same and more than 5.0 wt.%, the average friction coefficient and wear rate of copper–graphite composites were slightly higher than copper–copper-coated graphite composites; the current-carrying efficiency and current-carrying stability of the copper matrix composite were obviously higher than that of copper material; there was a mechanical wear area and arc erosion area on the wear surface of the composites, with the increase in graphite content, the adherence and the tear of the mechanical wear area weakened, the rolling, plastic deformation increased, and the surface roughness decreased obviously. The surface roughness of the wear surface of copper–copper-coated graphite composites with graphite content of 10 wt.% was 3.17 μm. The forms of arc erosion included melting and splashing, and were mainly distributed in the friction exit area.
Highlights
The current-carrying friction pair is a friction pair with a conduction current function [1], and its contact surface requires both a current conduction capability and friction and wear performance.Current-carrying friction is a process of coupling the frictional contact of a rough surface with conductive contact, accompanied by arc discharge and other phenomena [2,3]
Copper matrix composites are commonly used as current-carrying friction materials, and the copper matrix of the three-dimensional network structure satisfies the requirements of electrical conductivity, enhances the phase lubrication, and improves the friction and wear performance [6,7,8,9]
Co., Ltd, Shanghai, China), the density was measured by the drainage method, the hardness was microhardness tester (Laizhou Huayin Testing Instrument Co., Ltd, Laizhou, China), and the surface measured by a HV-1000 microhardness tester (Laizhou Huayin Testing Instrument Co., Ltd, Laizhou, roughness was measured by a nano focus three-dimensional topography instrument (Nanofocus AG, China), and the surface roughness was measured by a nano focus three-dimensional topography instrument (Nanofocus A G, Oberhausen, Germany)
Summary
The current-carrying friction pair is a friction pair with a conduction current function [1], and its contact surface requires both a current conduction capability and friction and wear performance. Previous studies have shown that the content of graphite has an important influence on the properties of the material and the friction and wear behavior Most of these studies focused on the condition of low speed (relative sliding velocity is less than 1 m/s), and with the expansion of the service conditions of the current-carrying friction pair, it is necessary to explore their service performance at high speed. In this study, pure copper, copper–graphite composites, and copper–copper-coated graphite composites were prepared by spark plasma sintering (SPS) using pure copper powder, natural graphite powder, and copper-coated graphite powder as raw materials, the effects of carbon content on current-carrying friction and wear properties of copper-based materials under high-speed sliding conditions were studied
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