Dimensional effects of electrically exploding aluminum wires in argon gas: Experimental investigation

Abstract

The strong dependence of electrical explosion of wires (EEW) on wire dimensions is demonstrated experimentally from three perspectives: electrical characteristics, spatial structures, and nanopowder properties. Electrical characteristics of EEW were explored by measuring current and voltage waveforms of exploding 20–100 μm-diameter and 2–10 cm-long wires in argon gas. The discharge mode, energy deposition, and breakdown characteristics of EEW were analyzed based on the calculation of several electrical parameters. Laser-based diagnostics and multi-frame photographs were used to obtain the EEW spatial structures and their evolutionary characteristics. The radial distribution of exploding wires in the early and diffusion stages was obtained according to the analysis of shadowgraphs and interference images. The optical observations suggested that nonuniformity of EEW spatial structures becomes appreciable with the increase of wire dimensions. Inhomogeneities in exploding wires (e.g., residual cores, gaps, local hot spots, and stratification phenomena) and the causes of their formation were also discussed. The morphology and particle size distribution of nanopowders produced by EEW were also observed via transmission electron microscopy as well. The statistical results show that increasing wire dimensions (diameter and length) increase the average diameter and broaden the size distribution of nanopowders.