Effect of Normal Load on the Current-Carrying Friction Performance of Copper–10% Graphite Composites

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.