Electrical Wire Explosion Research Articles

The synthesis of Fe-Ag and Fe-Cu bimetallic nanoparticles by electrical explosion of wires

In the present study, we obtained antibacterial Fe-Cu and Fe-Ag bimetallic nanoparticles by electrical explosion of two twisted wires. This method allows obtaining nanoparticles of a given composition and morphology. As-synthesized nanoparticles were characterized by electron microscopy, X-ray diffraction, micro electrophoresis techniques and magnet technique. In result we observed the formation of nanoparticles with Janus-like structure with distinct separation of components inside the particle. These nanoparticles have a strong antibacterial activity against two bacteria strains. The high antimicrobial activity of the nanoparticles is due to the prolonged ion release in media. Taking into account the possibility of easy magnetic separation of the novel bimetallic demonstrate the potential for their use as promising new generation antibacterial agents for advanced antimicrobial water treatment technologies.

Peroxymonosulfate activation by carbon-encapsulated metal nanoparticles: Switching the primary reaction route and increasing chemical stability

This study explores the technical merits of carbon encapsulation via an electrical wire explosion method to enhance the peroxymonosulfate activation performance of metals. Reflecting the nature of core-shell structures, the outer carbon layers hampered the reductive conversion of peroxymonosulfate to sulfate radicals by the inner metal cores, whereas the metal cores increased the overall electrical conductivity as a pivotal factor in non-radical activation. Hence, the impact of carbon wrapping hinged on the peroxymonosulfate reduction capability of the metals, i.e., kinetic retardation in organic degradation with reactive Cu, Fe, and Ni-Fe, but acceleration with unreactive Ni. Further, composite fabrication switched the major degradative pathway from radical-induced oxidation to mediated electron transfer, as determined from the effects of methanol and chloride, formaldehyde and bromate formation yields, reactivity toward multiple organics, and electron paramagnetic resonance spectral features. The protective carbon shells enabled pH-insensitive peroxymonosulfate activation, prevented metal ion leaching, and alleviated catalyst deactivation.

Study of burning rate characteristics of propellants containing Al–Mg alloy nanopowder

Nanopowder of Al–Mg alloy was synthesized using the method of electrical explosion of thin wires of hypo-eutectic Al–Mg alloy. Thin wires of hypo-eutectic Al–Mg alloy were cut by electrical discharge machining and exploded electrically. The nanopowder obtained is examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for studying the morphology of the particles. TEM and SEM images substantiate the spherical structure of the nanoparticles and the diameter of particles ranges from 20 nm to 95 nm. Solid propellants were prepared by adding the alloy nanopowder as an energetic additive element with bimodal ammonium perchlorate (AP) and Hydroxyl Terminated Polybutadiene (HTPB) propellant formulations. Burning rates of the propellant with nano Al–Mg alloy powder are compared with micro aluminised propellants and propellants with micro Al–Mg powder with the same composition. Mean burn rate of 22.03 mm s−1 was obtained at a pressure level of 9 MPa with nano Al–Mg powder and 20.4 mm s−1 with micro Al–Mg powder compared to mean burning rate of 10.03 mm s−1 at 8 MPa pressure for aluminised propellants. The improved mean burn rate of propellants containing Al–Mg alloy nanoparticles could be accounted for the reduction in the size of the alloy particle and selective melting of eutectic phases along with magnesium. In the process, it gives heat feedback to the high-temperature reaction zone, which results in augmenting further reaction of metal particles.

Experiments on the characteristics of underwater electrical wire explosions for reservoir stimulation

Underwater shock waves generated by pulsed electrical discharges are an effective, economical, and environmentally friendly means of stimulating reservoirs, and this technology has received much attention and intensive research in the past few years. This paper reviews the main results of recent work on underwater electrical wire explosion (UEWE) for reservoir stimulation. A platform is developed for microsecond single-wire explosions in water, and diagnostics based on a voltage probe, current coil, pressure probe, photodiode, and spectrometer are used to characterize the UEWE process and accompanying shock waves. First, the UEWE characteristics under different discharge types are studied and general principles are clarified. Second, the shock-wave generation mechanism is investigated experimentally by interrupting the electrical energy injection into the wire at different stages of the wire-explosion process. It is found that the vaporization process is vital for the formation of shock waves, whereas the energy deposited after voltage collapse has only a limited effect. Furthermore, the relationships between the electrical-circuit and shock-wave parameters are investigated, and an empirical approach is developed for estimating the shock-wave parameters. Third, how the wire material and water state affect the wire-explosion process is studied. To adjust the shock-wave parameters, a promising method concerning energetic material load is proposed and tested. Finally, the fracturing effect of the pulsed-discharge shock waves is discussed, as briefly are some of the difficulties associated with UEWE-based reservoir stimulation.

An Image Converter Camera for Studying Processes in the Nano- and Microsecond Ranges

A chronographic image converter camera has been designed on the basis of a PIF-01 image converter tube to obtain spatial and temporal information in a study of light processes in the nano- and microsecond ranges. The duration of scans on a 25-mm-diameter screen of the camera can be varied from 0.5 to 10 µs with a limiting time resolution of 2 ns or better. Possible applications of the developed camera for spectral and time measurements of processes in real experiments on the study of electric explosion of tungsten wires are described.

Spatial–temporal evolution of plasma radiation in electrical wire explosion: a morphological observation

This paper deals with an experimental study regarding the spatial–temporal evolution of single wire explosions in air and water at atmospheric pressure. Experiments were carried out with a microsecond timescale pulsed current source under 500 J stored energy. The morphology of the exploding wire with different discharge type, wire material, insulating coat, and ambient medium was intensively observed via self-emission images. The results revealed that the plasma radiation of wire explosion in air mainly contained two stages: initial intense radiation from optically thick plasma, and later decaying radiation from expanded arc-like plasma. A hollow structure was observed in a Cu exploding wire in air, and the plasma channel tended to develop inside it. As for W case, there would always be a core-corona structure, resulting in lower expansion rate and shock wave strength. Moreover, the plasma radiation of the underwater wire explosion was mainly determined by two factors: expansion rate and chemical reaction. The expansion rate of the radiant region in water was only 10–1 mm μs–1 level (1 mm μs–1 level for air), leading to the lagging radiation. No noticeable difference in morphology was found between Cu and W wire explosions in water. Particularly, the Al wire explosion generated a bright light emission due to chemical reactions. Finally, radiative characteristics in an exploding wire were preliminarily concluded and existing problems proposed.

Preparation of nano-Al powder with wire electric explosion

Nano-Al powder was prepared by wire electric explosion of different diameter aluminium wires. The results show that nano-Al powder particles appear spherical and agglomerate together, the surface was covered by Al2O3 layer. The particle size of nano-Al powder obey normal distribution and the average particle size increases with the increasing of wire diameter.

Comparison of underwater electrical wire explosions with large and small capacitors charged to a same energy

In order to investigate the effect of the current rise rate on the underwater electrical wire explosion (UEWE), two pulsed sources were used. One pulsed power source used an energy-storage capacitor of 1 μF while the other used a 200 μF capacitor. These two capacitors were charged to the same energy. The ratio of the current rise rate was about 11 for the UEWEs using these two pulsed sources at the same stored energy. In addition to the rise rate of the current, the wire resistance played an important role in affecting the energy deposition when it was comparable or even lower than the circuit resistance. The experimental results indicated that different capacitors may also lead to different discharge modes, even under the same energy storage and using the same size copper wire. It was found that the deposition energy, deposition power, the deposition ratio, and the discharge mode may influence the shock wave.

Synthesis of multiphase binary eutectic Al–Mg alloy-nanoparticles by electrical wire explosion technique for high-energy applications, its characterisation and size-dependent thermodynamic and kinetic study

Abstract In the present study, Al–Mg binary eutectic alloy nanoparticles were synthesized through the electrical wire explosion technique (EWET) in an inert ambience. High-speed imaging was carried out to visualize sublimation process of alloy wire and subsequent formation of nanoparticle through the condensation process. The fundamental gas-phase kinetics is investigated by the embedded atom method (EAM) and reactive hard-sphere model to elucidate the mechanisms governing the formation of finer particles of eutectic Al-Mg alloy. The condensed phase transformations are analysed through size-dependent thermodynamics and growth kinetics modelling, which has shown that the adsorption controlled growth is responsible for the generation of polydispersed particles. The formation of Al20Mg23 nanoparticles and its morphological features were characterised through XRD and SEM/EDS analysis. High-resolution transmission electron microscopy (HRTEM) along with the selected area electron diffraction (SAED) confirmed the spherical morphology, crystallinity, lognormal particle size distribution and the multiphase microstructure of the eutectic AlMg nanoparticles. The formation of multiphase alloy nanoparticles is attributed to the insignificant difference in melting temperatures of Al and Mg and phase boundary modifications due to size-effect. Scanning transmission electron microscopy (STEM) revealed the spatial distribution of Al and Mg within the alloy nanoparticle. Differential scanning calorimetry (DSC) confirmed the reduction in melting temperature and fusion enthalpy of eutectic Al–Mg alloy nanoparticles. It is proposed as a potential substitute for Al nanoparticles to reduce the ignition temperature, agglomeration and two-phase flow losses for realising improved combustion performance in solid rocket propellants.

Dynamic fracture and fragmentation of rock-like materials under column charge blasting using electrical explosion of wires

By using electrical explosion of metal wires, this study proposed a new experimental method to investigate the dynamic fracture process and fragmentation characteristics of rock-like materials under column charge blasting. A copper wire with a length of 100 mm was prefabricated in a mortar sample measuring 300 mm × 300 mm × 180 mm. High-voltage pulses were injected into the copper wire through an electric explosive device to produce an explosion load that could fracture the mortar sample. By virtue of an ultra-high speed camera, fracture processes on a free surface were observed. Moreover, changes in the fracture zone and fragments under an explosive energy of 1.68–5.67 kJ were studied. The results demonstrated that the crushed zone increased with the rise of explosion energy; however, the volume, perimeter, and breakage angle of the blasting crater, as well as the size of fragments decreased with increasing explosion energy.

Effects of circuit inductance on electrical and shock wave characteristics at underwater wire explosion

Circuit inductance is an important parameter at underwater electrical wire explosion (UEWE) experiments as it closely relates to the energy deposition rate to the load wire. In this study, the circuit inductance was varied within a wide range from 1.55 μH to 93.2 μH by inserting inductive coils to study its effects on electrical and shock wave (SW) characteristics at UEWE. Experimental results showed that UEWEs using thinner wires were less affected by the increase of circuit inductance and the SW peak pressure several-cm away from the wire is not sensitive to the increase of circuit inductance if properly choosing the diameter of load wire: the maximum SW peak pressure obtained with varied diameter (constant energy storage and wire length) only saw a decrease of 30% as the circuit inductance increased by 60 times from 1.55 μH (0.3 mm diameter, 19 MPa) to 93.2 μH (0.2 mm diameter, 13 MPa). Hydrodynamic calculations were used to explain the experimental results. These results indicated that for a practical UEWE system, the energy storage can be far away from the load while keeping an acceptable loss of the capability of generating strong SWs, which greatly improves the flexibility of system designing for example by enabling much larger energy storage for certain harsh working environments.

Experimental Study of Pressure Waves upon the Electrical Explosion of Wire under the Conditions of Elevated Hydrostatic Pressure

The results of the experimental studies on the effect of hydrostatic pressure, charge voltage, stored discharge energy, and wire diameter on the amplitude of a pressure wave upon an electric wire explosion in water are presented. It is shown that the amplitude of the pressure wave generated in a liquid increases with an increase in the stored energy and charge voltage, and at an optimum diameter of the wire, the maximum amplitude of the pressure wave is ensured. When hydrostatic pressure is elevated, an amplitude decrease of the generated pressure wave was observed for a thin initiating wire (0.14 mm diameter), and no effect was observed for a thick wire (0.5 mm diameter or larger). In addition, the need to ensure a good hard contact between the electrodes of the electrode system and the metal wire during the electrical explosion of the wire in a liquid was shown, in default of which there is a loss of the efficiency of the mechanical action occurs owing to a decrease in the amplitude of the pressure wave.

Spark Plasma Sintering of the Ni-graphite Composite Powder Prepared by Electrical Explosion of Wire in Liquid and Its Properties

In this work, the electrical explosion of wire in liquid and subsequent spark plasma sintering (SPS) was introduced for the fabrication of Ni-graphite nanocomposites. The fabricated composite exhibited good enhancements in mechanical properties, such as yield strength and hardness, but reduced the ductility in comparison with that of nickel. The as-synthesized Ni-graphite (5 vol.% graphite) nanocomposite exhibited a compressive yield strength of 275 MPa (about 1.6 times of SPS-processed monolithic nickel ~170 MPa) and elongation to failure ~22%. The hardness of Nigraphite composite had a value of 135.46 HV, which is about 1.3 times higher than that of pure SPS-processed Ni (105.675 HV). In terms of processing, this work demonstrated that this processing route is a novel, simple, and low-cost method for the synthesis of nickel-graphite composites.

Fabrication of nanocomposites by electric explosion of stainless steel capillaries filled with carbon nanotubes

Conventional electric explosion of wires (EEW) method can produce carbon nanotubes (CNTs) based nanocomposite with little impact on the CNTs, but complicated due to the liquid operations. A novel EEW method with micro-tubular metallic material filled with CNTs water solution was proposed to fabricate the CNT-based composite. The fabrication process of the products could be extremely fast comparing to the conventional EEW in the CNTs’ aqueous solution, and the composites are directly deposited on the substrates without further separation and purification procedures. Microscopic morphology analysis of the as-prepared deposited film samples reveals that the nanocomposites consisting of metallic nanoparticles and the CNTs were obtained. The compounds with Fe-C bonds existed in the CNT-based nanocomposites generated in the explosive products. Beyond the demonstrated CNTs and steel, this method can be a general framework for the deposition of metallic nanoparticles and liquid-soluble one-dimensional nanomaterials.

Carbon-coated tungsten diselenide nanosheets uniformly assembled on porous carbon cloth as flexible binder-free anodes for sodium-ion batteries with improved electrochemical performance

As large-scale energy storage systems, rechargeable sodium-ion batteries (SIBs) are promising to replace the lithium-ion batteries. Among transition-metal dichalcogenides, which exhibit high theoretical capacities and specific two-dimensional layered structures, tungsten diselenide (WSe2) is an efficient anode material for SIBs owing to the good energetics and large lattice parameter. In this study, well-crystallized WSe2 nanosheets uniformly assembled on a porous carbon cloth (WSe2@PCC) were fabricated by an underwater electrical explosion of a tungsten wire, dip coating, and complete selenization from WO3 to WSe2. To further improve the cycling performance of the WSe2@PCC electrode, a carbon coating was carried out by simply adding sucrose into a WO3 ink before dip coating. The carbon-coated WSe2@PCC (C@WSe2@PCC) electrode exhibited outstanding electrochemical performances as a flexible and binder-free anode for SIBs due to enhanced electrical conductivity and mitigation of volume expansion of WSe2 during repeated sodiation/desodiation. Benefiting from unique structural merits and efficient carbon coating, C@WSe2@PCC can deliver large reversible areal capacity of 1.37 and 1.05 mA h cm−2 at the 1st and 150th cycles, respectively, with excellent capacity retention and Coulombic efficiency even at a high current density of 0.75 mA cm−2.

Oxidation of Fine Tantalum Particles: Metastable Intermediates and Multistep Kinetics

The metastable tantalum suboxides have been found to be a cause of complicated oxidation behaviour of fine tantalum particles when heated in air at moderate temperatures. Fine Ta 0.02–10 μm particles of bimodal size distribution with average volume maxima of 0.12 and 4 μm were prepared via electric explosion of thin Ta wire in Ar atmosphere. The oxidation reaction proceeded via several intermediate suboxides (Ta6O, Ta4O, Ta2O and TaO2) in which chemical and structure transformations caused multistep kinetics of the oxidation process in a narrow temperature interval of 250–570 °C. Within the interval of 250–400 °C, the oxidation process occurred under diffusion control with an apparent activation energy Ea,1 = 31.6 ± 1.2 kJ/mol and the main oxidation products were Ta(O) solid solutions and suboxides Ta6O and Ta4O. In the interval of 400–520 °C, oxidation was accompanied by a low-barrier martensite-like transformation of the lower suboxides resulting in reducing of diffusion limitations of the process (Ea,2 = 4.8 ± 1.2 kJ/mol). In the interval of 520–570 °C, oxidation of the larger Ta particles was completed to form Ta2O (Ea,3 = 64.7 ± 1.9 kJ/mol). An abrupt decay of Ta2O at temperatures greater than ~ 570 °C induced the high-rate oxidation of micron-sized Ta particles, resulting in self-heating of the sample.

Закономерности формирования структурно-фазовых состояний биметаллических наночастиц Ag-Cu, полученных электрическим взрывом двух проволок

In present work we observed structural phase state formation of Ag-Cu nanoparticles by electrical explosive of wires. We observed the formation of bimetallic nanoparticles with a number average size of 75 ... 82 nm by synchronous and nonsynchronous electric explosion of wires. The phase composition of the samples is represented by phases based on solid solutions of copper and silver. The results of the studies allow us to conclude that, using electric explosion of copper and silver wires, bimetallic Ag-Cu nanoparticles with different mass ratio of metals can be obtained.

Детектирование клеток, содержащих интернализованные мультидоменные магнитные наночастицы оксида железа (II, III), методом магнитно-резонансной томографии

This study evaluated the feasibility of using uncoated iron (II, III) oxide nanoparticles (IONP) obtained by electric explosion of wire in air for labelling living mesenchymal stromal cells and their subsequent visualization by magnetic resonance imaging (MRI) using 1.5T clinical MRI scanners. The uptake of uncoated IONP by MSC was demonstrated for the wide range of IONP concentration in the cell culture medium. The cells did not change their proliferative activity, viability, and the set of surface markers. IONP obtained by electric explosion of wire in an atmosphere of air had a shape close to spherical. The size of nanoparticles varied from 14 to 136 nm according to dynamic lateral light scattering, laser diffraction, and transmission electron microscopy. Particles up to 136 nm comprised 75%, and particles less than 36 nm --- 10% of the IONP powder. A wide range of particle sizes made it possible to select MRI parameters suitable for labelled cells detection in animal tissues both in the T2 mode and in the T1 relaxation mode.

High-rated loading, deformation and fracture of thick-walled composite cylinders with an electric explosion of wires

The technique of experimental testing and estimation of failure strengths for composite thick-walled 2-component cylinder proposed. We estimated amplitude of the generated by the wire explosion pressure and portions of this pressure transmitted into the PMMA cylinder and the aluminium shell. Dependence between cylinder radius and radial pressure measured and recorded with developed by us piezo-probe. Failure stress for the PMMA cylinder as well as failure strass of the aluminium shell is also estimated.

Структура, морфология и антибактериальные свойства мезопористых нанокомпозитов AlOOH-металл

The risk of development of resistance in Staphylococcus aureus to the antibiotics and antiseptics leads to the search of new efficient antibacterial agents for biomedical applications. In present work, bimetallic Al-Cu, Al-Ag nanoparticles were synthesized by the electrical explosion of wires in argon atmosphere. The mass ratio of aluminum and Me (Me = Cu, Ag) was ~90:10 and was controlled by the diameter of the dispersible metal wires. Mesoporous AlOOH-Me composite were fabricated by the environmentally friendly process of Al-Me nanoparticles water oxidation at 60°Ϲ. The kinetic regularities of the Al-Me nanoparticles conversion in diluted aqueous suspensions were studied. The influence of second metal on the structure, morphology and antibacterial activity of nanocomposites against methicillin-resistance Staphylococcus aureus (MRSA) was investigated. The synthesized AlOOH-Me nanocomposites possessed high antibacterial activity. The results indicated that the as prepared AlOOH(Me) composite have a potential application in biomedical applications.