Effect of Internal Electrical Field on the Electrical Breakdown Properties of Contact Materials

Abstract

In order to get a deep understanding of the effect of internal electrical field on the electrical breakdown properties of contact materials, two kinds of W-Cu and Cr-Cu joints were prepared in a vacuum sintering furnace. The vacuum breakdown tests were respectively performed at the interface of two joints and pure metal ends in an arc extinguishing chamber, and the surface morphologies after electrical breakdown 50 times were characterized by a scanning electron microscopy equipped with an energy dispersive spectroscopy. The results show that the breakdown strength at the interface is much larger than that of pure metal ends, and the breakdown site deviates from the interface. It is suggested that the existence of internal electrical field at the interface of two contact metals changes the electronic structure, and, thus, the electrical breakdown behavior is influenced.