On the Contact Resistance of the Film on Electric Contacts

In this paper some results obtained from the experiments on the contact resistance of the films formed by discharge on Ag, W, Cu and other several alloy contacts are given. The contact resistance was measured closely point by point, with a Ag needle mounted on a special measuring apparatus.The results obtained are as follows: On the anode surface, some cathode material is transferred and the distribution of contact resistance shows a complicated structure. On the cathode surface a new heat resisting surface is formed by discharge, and, consequently, the contact resistance of the cathode is very low. On heating, the contact resistance of Ag and Cd against the Ag needle decreases, while that of W,Cu and others increases.In the case of alloy contacts, these films are composed of oxides of the alloying elements.