Structural Analysis of Electrical Contacts Based on Displacement Energy of Atoms and Its Application to Sheet Contact with Low Contact Load

摘要

We have proposed a new model of electrical contact from a viewpoint of atomic displacement, and analyzed the equilibrium energy for the contact. Based on the model, a contact load provides the equilibrium energy to form an effective contact area generated by metallic bonds between a contact material and a substrate. The contact consists of two main conducting modes: one is bulk conducting and the other is tunneling mode. According to the two modes, contact resistance is expressed as a power function and an exponential function. To demonstrate the model, we have developed a novel electrical contact structure composed of thin metal films on an elastomer substrate. By employing this contact configuration, the tunneling conducting mode becomes dominant due to a sheet contact instead of a conventional point contact. Moreover, there is no dent due to the sheet contact with low contact load. Highly stable and low contact resistance of <100 mΩ was attained even under such low load of 0.002N. The experimental results are in good agreement with those predicted from the model.