Effects of current load on wear and melt erosion of electrical contacts under fretting condition.

In this work, the wear and melt erosion behavior of tin-plated copper alloy contacts are investigated under fretting at current loads ranging from 0.1 to 12.5 A. Three typical variations in the average values of contact resistance and contact temperature with fretting cycles are recorded and interpreted explicitly. The material melt erosion in the contact interface is observed clearly at currents higher than 5 A due to substantial Joule heat. The increment of contact temperature together with the distortion of transient friction force are considered as the degradation characteristics in the fretting. The produced scars and oxides between the contact interface eventually lead to the electric circuit disconnection. The distinct physical mechanism of contact interface fretting wear and melt erosion at high current loads is presented. [ABSTRACT FROM AUTHOR]