Effect of Rotation Speed on the Tribological and Conductive Behaviors of Rolling Current-Carrying Cu Pairs

Abstract

The tribological and conductive performance of the rolling current-carrying pairs were studied at different rotation speeds based on the disc-disc Cu pairs. Whether the current was applied or not, the friction coefficient decreased with the increasing of rotation speed. The average contact resistance increased with the rotation speed and the applied current. The sharp fluctuation of the real-time current was proposed as the failure criterion for the rolling current-carrying pairs, and both the rotation speed and the current accelerated the failure process. Erosion pits and melting could be observed by SEM, and the surface oxidation could be detected by EDS on the failure surface. It was speculated that arc discharge appeared under high speed and large current conditions, which encouraged the transformation of damage mechanism from mechanical wear to arc erosion. These results may provide some useful suggestions on the failure mechanism and life tests of the electro-conductive rotary joints.

Fig. 2 Sketch map of the rolling pairs. (a) Disc-disc contact; (b) Schematic diagram of the appearance; (c) Schematic diagram of the rolling contact and electrical circuit system.