In Situ Interface Characterization of Arcing Electrode Materials and Evolution in Electrical Endurance Experiments

The interface physics is very important to the electrical contact reliability of current switching devices. In this article, the arcing electrode material surface topographies are measured consecutively in the electrical endurance experiments. A novel data processing algorithm is proposed for reconstructing the real contact interface between electrodes. The characterization parameters of contact interface including a-spots number, area, centroid distance, and contact resistance are extracted. The comparison between the experimental recorded resistance and the analytical calculation results shows the validity of the proposed method. In the electrical endurance testing, three typical evolution stages of electrical contact interface are presented and analyzed. The contact spots are limited to the surface peaks in the initial operations, and then distributed evenly across the whole electrode surface. At the end of the testing, the contact area decreases slowly with the shrinkage of central convex face. It is determined that the electrical material redistribution caused by the arc erosion is the root reason for the contact interface evolution.