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.

The tribological performance of copper-based powder metallurgical material is much influenced by the interfacial bonding between the components and matrix. By adding Cu-coated or uncoated graphite particles as a lubricant, two types of copper-based powder metallurgical materials were prepared via spark plasma sintering (SPS). The hardness, relative density, and thermal conductivity of the two specimens were firstly measured. Using an inertial braking test bench and temperature measuring instrument, the average friction coefficients, instantaneous friction coefficients, and friction temperatures of the two specimens were tested under different test conditions, and the wear rates were calculated accordingly. Based on the analysis of surface morphologies and elements distribution after the tests, the mechanisms of wear and formation of friction films were discussed. The results show that with the lubricant of Cu-coated graphite, the hardness, relative density, thermal conductivity, and interfacial bonding between the graphite and matrix can be greatly improved. Under the same test condition, the average friction coefficient, wear rate, and friction temperature of the specimen with added Cu-coated graphite are both lower than those of the specimen with added uncoated graphite. The two specimens show different variation trends in the instantaneous friction coefficient during the tests, and the variation of the instantaneous friction coefficient at a high initial test speed is also different from that at a low initial test speed for each specimen. The two specimens also show differences in the continuity of friction film and the content of graphite and oxide in the friction film.

Copper-graphite composites were prepared by spark plasma sintering (SPS) with copper powder and copper-coated graphite powder. The effect of particle size of raw material powder on the current-carrying friction properties of copper-graphite composites was studied. The results show that the friction coefficient of the composites decreased with the decrease of the particle size of copper-coated graphite powder, the friction coefficient of the composites increased with the decrease of the particle size of the copper powder, the wear rate of the composites increased with the decrease of the particle size of the copper-coated graphite powder, and the wear rate of the composites increased significantly with the decrease of the particle size of the copper-coated graphite powder. The current carrying properties of composites with different particle size ratios and QCr0.5 pairs are good and fluctuate little. The current-carrying friction properties of 150 μm copper powder and 75 μm copper-coated graphite powder were found to be the best. The wear surface could be divided into mechanical wear area and arc erosion area. The main area of arc erosion was less than 15% of the total area, and it was mainly distributed in the friction outlet area. The main forms of mechanical wear included furrow, rolling deformation, cold welding, and tearing, among other forms. Graphite film was formed on the surface. The surface quality of the composite prepared by 150 μm copper powder and 75 μm copper-coated graphite powder was the best, the Sa was 3.22 μm, rolling deformation was the most adequate, no large tear pit and furrow appeared, and the carbon content on the worn surface was much higher than that in the composite. The behavior of arc erosion was mainly melting and splashing, and the particle size of the original powder had little effect on it.

To investigate the effect of the initial surface roughness on the performance at the initial stage of the current-carrying friction of an elastic friction pair, experiments were conducted using a self-made current-carrying friction and wear tester. The results indicate that under the experimental conditions, the lifespan of the friction pair decreases as the surface roughness and load decrease. When the surface roughness is Ra 0.2 μm and the load is 0.025 N, the lifespan is the longest, reaching 320 cycles, with an average contact resistance of 0.045 Ω and a standard deviation of 0.009 Ω. During the normal service period of the friction pair, the main wear mechanism is furrowing. As adhesion and tearing occur, the electrical contact performance begins to degrade. The impact of arc erosion on the wear surface is far greater than that of mechanical wear. This provides a reference for the design and manufacture of current-carrying friction pairs represented by connectors.

A copper-10 wt.% graphite composite was paired with QCr0.5 to investigate the effects of normal load on current-carrying friction behavior. Arc discharges were monitored using a high-speed camera and photodiodes. The results indicate that, under the given experimental conditions, normal load predominantly influences the tribological performance of the material. As the c normal load increases, the wear rate decreases rapidly at first and then increases gradually. The optimal normal load was found to be 70 N, at which the wear rate reached a minimum of 0.46 mg/m. Material degradation was found to consist of mechanical damage—mainly plowing and plastic deformation—as well as arc-induced erosion characterized by melting and spattering. With increasing normal load, arc erosion decreased progressively, and the overall damage was minimized at 70 N. Arc erosion contributed to surface wear non-uniformity. Moreover, particular attention should be paid to high-current, long-duration arcs, which can pose serious localized threats to material integrity.

Given the significant impact of the initial surface layer of materials on their tribological performance, this study uses a wire–plate reciprocating friction pair to investigate the effects of surface mechanical rolling process on the elastic current-carrying friction performance. The plate specimens were subjected to rolling processing with varying feed rates under different load conditions, using a self-designed current-carrying friction and wear testing machine. The results show that as the feed rate and load increase, the contact resistance varies within the range of 0.0065 Ω to 0.0310 Ω, with a standard deviation ranging from 0.01 Ω to 0.07 Ω, indicating good electrical conductivity. As the feed rate of the surface mechanical rolling increases, the wear rate of the material significantly decreases. Under all test conditions, the material wear marks exhibit plowing wear, and with the increase in surface mechanical rolling feed rate, the occurrence and intensification of adhesive wear are delayed. When the feed rate is 100 μm and the load is 0.025 N, the material wear rate is the lowest, reduced by 63.1% compared to the untreated condition.