Analysis of Contact Resistance Behavior for Electric Contacts with Plating Layer

It is very important to predict the force-contact resistance relation for the virtual connector designing. In this study, the prediction of electrical contact resistance in various cases was examined. The specimens consisted of a copper alloy with tin or silver plating. To predict the contact resistance at each contact force, the relationship between contact resistance and contact force were separated into two parts as the force-contact area relationship and the contact area-resistance relationship. The force-contact area relationship was predicted by using Finite Elemental Modeling (FEM) contact analysis. The contact area-resistance relationship was analyzed by the theory of constriction resistance with plating layers. To combine these relations, the prediction of force-resistance relation is obtained. As the results, the experimental results of the silver plating sample, which has no oxide film, were in good agreement with the prediction results, and the experimental results of the tin plating sample, which has oxide film, were in agreement with the prediction results in high-load region of practical use of a terminal connector in which constriction resistance is dominant. Therefore, this technique is useful for the virtual connector designing.