Understanding the nanoparticle formation during electrical wire explosion using a modified moment model

Abstract

Electrical explosion of wires (EEW) was carried out in an argon atmosphere for the preparation of nanoparticles. Aluminium wires with 0.1 mm diameter and 13 cm length (low mass) and 0.4 mm diameter and 11 cm length (high mass) were used, for which the vaporization energy of the wire was, respectively, far below and comparable to the initial stored energy of the powersupply capacitors. A numerical model was used to study the nanoparticle formation within the exploding wire plasmas. The model is based on a moment method and was modified according to the specific requirements of EEW-rapid expansion of the exploding wire and a high concentration of monomers-to take into consideration the quenching due to mechanical work on the surrounding medium, the energy release during the vapour-liquid phase transition, and the coagulation of liquid particles. The calculation took initial and boundary values from the experimental results and predicted average particle diameters of 36 nm and 116 nm for the low mass and high mass wire respectively, which are in qualitative agreement with the experimental values of 33 nm and 103 nm obtained from SEM images. The nucleation mechanisms including homogeneous nucleation and ion-induced nucleation are discussed in detail; the importance of including the phase transition and coagulation is demonstrated.

Laser scattering by submicron droplets formed during the electrical explosion of thin metal wires

“…Investigations of an electrical wire explosion (EWE) have great importance for fundamental physics of condensed matter in extreme states [1,2] and multiple applications, e.g. soft xray radiography [3], nanopowder manufacturing [4][5][6], underwater shockwave production [7][8][9][10][11], current switching [12] and many others. Basically, a wire explosion in vacuum, as well as in liquid or air media is understood as a complex transformation of the metal at a high current density into different forms of matter which, in particular, are metal vapor and foam, plasma, fine-scale droplets and liquid microdrops.…”

A combined theory for magnetohydrodynamic equilibria with anisotropic pressure and magnetic shear

“…A common approximation in these sorts of models is to assume that the shear field is precisely equal to the function F (e.g. [13,31,32]), which would imply that / φ b F is unity everywhere in the domain. Thus, apart from demonstrating how the method can be used in general, this example also demonstrates that setting the shear field equal to F(A) may not be an approximation which is generally valid.…”

Structural, Mechanical, and Tribological Characterization of Magnetic Pulse Compacted Fe–Cu Bimetallic Particles Produced by Electric Explosion of Dissimilar Metal Wires

“…Both theoretical and experimental studies show that nanoparticles are formed during EEW by means of condensed cluster coagulation in the expanding EEW products [25][26][27][28]. These clusters are generated during EEW as a result of inhomogeneous energy release at the crystallite boundaries and instabilities caused by such an overheating so that the metal becomes fragmented into the nanosized clusters [29][30][31].…”