Deteriorating mechanisms of silver and tin plated copper connectors subjected to an oscillating movement

The influence of vibration on the deterioration of the contact surfaces of a separable connector system is studied. The connector has a movable plug-in part and a stationary bus bar. Both contact members are made of electroplated copper. Which deterioration processes are dominant for different combinations of material and contact parameters is discussed, and how they relate to contact resistance and friction force is addressed. The influence of normal load, coating material (Ag, Sn), and lubrication on wear and contact resistance in current loaded connections are investigated in laboratory tests. Extensive scanning electron microscopy of surfaces and cross-sections of the contact areas are used to study the processes. Short time vibration tests proved to be a valuable means for investigating the performance of electrical contacts. It is concluded that with the most beneficial parameter combination, high load and application of grease, the two tested material combinations behaved equally well