Mechanism of current injection in the process of wire electrical explosion

In the process of nanopowder production by the wire electrical explosion, the ablation of electrodes and the formation of micronsize particles are directly influenced by the way the current is injected into the metal wire from the electrodes. Through the channels which are provided by the "contact" between the electrodes and the wire ends, as well as the "breakdown" between them, a series of experiments of electrical explosion is carried out. Results show that the photocurrent detected by photodiodes at the wire ends almost occurs simultaneously with the circuit discharge current, however it at the central section lags behind the circuit discharge current obviously. The initial explosion product of the wire ends is liquid, and that of the other parts of wire is gas. Those results indicate that when the current folows into the "contact", the phenomenon of gas discharge also occurs at the wire ends. Because the plasma provides another current path, the energy density of the wire ends is decreased. Hence, the wire ends cannot explode and form remainder on the electrodes. When the current flows into the "breakdown", the electrodes ablated is slightly obvious, and there was no remainder on the electrodes.