Effects of current load on the triboelectric properties and wear mechanisms of gold-plated copper alloy pairs

The wear rate also increased with the increasing current, while the value turned negative at 20A indicating that the sample volume increased due to the interface material transferring. As for electrical properties, the contact resistance and its fluctuation value both decreased as the current increasing. In summary, with the current increasing, the frictional and wear performances degraded and the quality of contact surface deteriorated, but the electrical contact properties improved.

As for wear mechanisms, furrows and plastic deformations dominated at relative lower currents (5A and 10A), while adhesive wear made a great contribution at relative higher currents (15A and 20A). The calculational results demonstrated that that Joule heating power was much larger than the frictional heating power, which dictated the interfacial temperature rise. And the maximum temperature of the contact interface is 78.0 ℃ at 20A obtained by finite element calculation.

Therefore, the temperature rise due to Joule heating led to material softening, resulting in the contact area increase, and thereby causing the rise of friction coefficient and the decrease of contact resistance. On the other hand, the strength decreased after material softening, which promoted adhesive wear. This study is expected to provide theoretical support for the material design and damage protection of the contact pair in high-power electrical connectors.