Observation of arc discharging process of nanocomposite Ag–SnO2 and La-doped Ag–SnO2 contact with a high-speed camera

Nanocomposite Ag–SnO2 and La-doped Ag–SnO2 electrical contact alloys were prepared by chemical co-precipitation method and hot-pressing sintering technique, and their arc discharge process were observed using a high-speed camera. Experimental results show that the arc discharge process in gases can be divided into three stages: arc formation, steady burning and attenuation. Compared with nanocomposite Ag–SnO2 contact alloy, La-doped nanocomposite contact alloy exhibits longer arc formation and steady burning time and bigger volume of the plasma clouds as well as dimmer arc-emitting spectrum. Also, the arc roots move very fast, and spread over a larger area on the surface of La-doped nanocomposite cathode. As a result, the melting of the cathode is slight, demonstrating a better performance of arc erosion resistance.