The Device And Process Research Of Auto-continuous Wire Electrical Explosion On Preparing Nano Metal Powders

As a new method for preparation of metal nano-materials, electric explosion of wires (EEW) has many advantages in the field of nano-materials processing, and is considered as a preparation method for large-scale industrial nanopowders. Reported EEW devices are difficult to achieve efficient, continuous and stable preparation process, which makes the method in practical engineering applications subject to certain restrictions.Based on gas discharging in current mechanism, a device for nanopowders production by auto-continuous EEW was developed, which consists of wire feeding device, high-voltage circuit, high voltage electrodes, explosion chamber and powder collecting device. And the device can achieve a stable and reliable automatic continuous electrical explosion process, which has high degree of mechanization, easy operation and high production efficiency. This paper put N6pure nickel wire as raw materials to test at different initial charge voltage. The prepared nano nickel powder particles were subjected to statistical analysis and characterization. The electrical signals of one electric explosion process at different initial charge voltage and the capacitor’s charging and discharging were measured, and the characteristics of energy deposition at different initial charge voltage were calculated.The macro morphology of the Ni nano powder was grey, through the TEM microscopic observation found that, when the particle size was small, the particles were approximately cube-shaped, when the particle size was larger, the particles were spherical or spheroidal. Phase detection by XRD analysis showed that the prepared nano powders was mainly composed of Ni and NiO. Increasing the initial charging voltage which is applied to increase the initial energy of the wire could reduce the range of Ni nano particle size distribution effectively. But when the initial charging voltage was more than7kV, with the initial charge voltage increasing, the decrease of the average particle size dmean, standard deviation σ and the maximum particle diameter dmax significantly reduced, and the average particle size of Ni nano powders which had uniform particle size was less than30nm. The higher initial charging voltage was, the higher peaks of voltage and current waveforms were, the shorter duration of EEW process was, and the faster energy deposition rate was significantly. The total energy deposited in the wire also increased with increasing the initial charge voltage. The energy and the energy deposition rate could be increased by increasing the initial charge voltage to provide enough energy for preparing nano metal powders.