Degradation of contact materials — Effects of time, temperature and wear

Knowledge of the contact resistance-contact force characteristics is essential for the design and diagnostics of electrical contacts, especially for low pressure contacts in connectors. Since the electrical contacts often have to be mated after a long period of storage, not only the characteristics of virgin contact surfaces but also those of aged contact surfaces are of substantial importance. The current study focuses on new, thermally aged contact materials and contact materials, which have experienced fretting wear. The contact resistance - contact force characteristics of differently degraded contact materials are compared. Depending on the kind of materials, different effects of degradation can be observed. Both the model calculation and the surface analysis are conducted in order to gain a better understanding of the mechanisms, which influence the characteristics of the contact resistance.