High Speed Imaging Observation on Molten Bridge of AgSnO2 Electrical Contact Material

An electrical contact-high speed imaging experimental system was developed to study the basic characteristics and laws of molten bridges of AgSnO2 electrical contact material. On the one hand, the quantitative measurements were investigated by high speed imaging technology. On the other hand, the microstructure and element distribution on the surface of contacts were analyzed by SEM and EDS after molten bridges behavior. Results indicate that the evolution behavior of molten bridges of AgSnO2 contacts can be divided into three regimes: the initial melting period, a stable period and an unstable period during which it eventually ruptures. Molten bridges and arc can exist simultaneously in which there is some cooperation and competition relationship. The dimension of molten bridges of AgSnO2 contact material is micron scale, the diameter of molten bridges increases with the increase of current and the length decreases with the increase of current. In the process of the evolution behavior of molten bridges, the feature of molten bridges can be divided into three types: the pier, follow by the cylindrical and the dumbbell. The morphology and element distribution of the contacts surface are changed by the behavior of molten bridges.