Influence of Energy Deposition on Characteristics of Nanopowders Synthesized by Electrical Explosion of Aluminum Wire in the Argon Gas

The energy deposition during the wire electrical explosion process plays an important role in the expansion of metallic vapor and conductive plasma for the nanopowders preparation. In this paper, aluminum nanopowders are synthesized by electrical exploding aluminum wire in the argon gas under different charging voltages of the capacitor. The influence of the deposited energy E and the argon gas pressure p on the characteristics of aluminum nanopowders is studied by the transmission electron microscope (TEM). Due to the effect of argon gas pressure on the energy deposition, a plasma expansion parameter Ep^-1 is proposed to summarize the synthesis conditions. The results show that the morphology of aluminum nanopowders was mainly dependent on the argon gas pressure rather than deposited energy. Lower deposited energy and higher pressure of argon gas could broaden the particle size distribution range of aluminum nanopowders evidently, which is ascribed to a smaller plasma expansion volume. The count mean diameter of aluminum nanopowders decreases monotonically with the increasing plasma expansion parameter Ep^-1. The value of relative standard deviation ranges from 0.38 to 0.5 in the experiments. It has been demonstrated that the size uniformity of nanoparticles can be improved by reducing the energy deposition rate when the pressure of argon gas and deposited energy remains virtually unchanged.