Electrical Wire Explosion Research Articles

Synthesis of tungsten carbide from bimodal tungsten powder produced by electrical explosion of wire

In the present study, bimodal tungsten carbide WC powders are successfully prepared by a two-stage process: electrical explosion of wire (EEW) synthesis of bimodal tungsten powder followed by a carburization reaction. The conditions of the EEW synthesis have been determined, resulting in the preparation of the bimodal powder. During the carburization process, the tungsten carbide WC is formed through the transition phase W2C. The carbon content in the obtained WC powders is very close to the theoretical value. Also, it was found that a high C/W molar ratio at the carburization stage does not affect the carburization process significantly. Optimal conditions for the tungsten carbide WC synthesis have been determined: calcination at 1200 °C with 8 h dwell and C/W molar ratio to be 1.4. The yield of tungsten carbide is 99 wt% under these conditions. Thus, the carburization process of bimodal tungsten powder may provide a low-cost and high-efficiency route to prepare the WC powders for various applications.

Improved oxidation stability of carbon-coated Ni nanoparticles synthesized by one-step electrical wire explosion

This study demonstrates a rapid one-step route to prepare high-purity carbon-coated Ni (Ni@C) nanoparticles via electrical wire explosion in methane gas used as a carbon source, and also investigates an oxidation stability of Ni@C nanoparticles. The Ni@C nanoparticles have smaller average particle size and narrower particle size distribution than the passivated Ni (Ni@P) nanoparticles and show positive dependence of carbon layer thickness on core Ni particle size. The thermal oxidation of Ni@C nanoparticles is closely related to the burn-off of protective carbon shells. From a thermogravimetry analysis to investigate the oxidation kinetics of Ni nanoparticles, the activation energy Ea for oxidation of Ni@C nanoparticles is determined to be 161.31–170.34 kJ mol−1, which is much higher than the Ea value (81.22 kJ mol−1) of Ni@P nanoparticles. This confirms that the carbon shell effectively prevents the active core Ni nanoparticles from high temperature oxidation in air.

Preparation of Nano/Micro Bimodal Aluminum Powder by Electrical Explosion of Wires.

Electrical explosion of aluminum wires has been shown to be a versatile method for the preparation of bimodal nano/micro powders. The energy input into the wire has been found to determine the relative content of fine and coarse particles in bimodal aluminum powders. The use of aluminum bimodal powders has been shown to be promising for the development of high flowability feedstocks for metal injection molding and material extrusion additive manufacturing.

One hundred kilojoules of energy storage in water wire electric explosion deposition energy study

In this experiment, the electro-explosive deposition energy in water of aluminum-magnesium welding wire model ER5356 at 100 kJ capacitive storage energy was investigated. The loop current and the load discharge voltage during the wire electrical explosion were measured using a self-integrating Roche coil and a capacitive voltage divider, respectively. The physical process of electrical explosion and the energy deposition process were delineated by the measured loop currents and load voltages. The current waveform and load voltage of the electric explosion in water of 1.2 mm-3.0 mm diameter Al-Mg wire at 100 kJ stored energy were measured; the changes of load resistance value, load power and deposition energy of the wire loaded with electric explosion were calculated. The results show that the peak circuit current and peak time point decrease and then increase with increasing diameter, and the minimum value is achieved at 1.6 mm wire diameter; the load voltage and load resistance values gradually decrease with increasing diameter; the load power and total deposited energy of discharge achieve the maximum value at 2.0 mm diameter. At 100 kJ energy storage, there is an optimal range between 1.6 mm and 2.4 mm wire diameter.

Detonation of a nitromethane-based energetic mixture driven by electrical wire explosion

The combination of energetic material (EM) and an electrical wire explosion (EWE) is an important way to achieve effective release and conversion of electrical and chemical energy, e.g. by generating strong underwater shock waves (SWs) that can be used for dynamic reservoir fracturing in unconventional gas exploitation. This letter proposes a mud-like EM composed of nitromethane, aluminium and copper oxide powder, which can be detonated directly by a tungsten wire explosion. The detonation and successive deflagration result in notably enhanced SWs: with 2.8 g EM, the SW amplitude, impulse and energy are respectively increased by 1.7, 2.1, and 7.9 times compared to an optimal underwater EWE. A direct thermal initiation mechanism for the detonation process is proposed, with the exploding wire, the Joule heating along the current path in the EM and the Al/CuO thermite reaction all serving as heat sources. It is found that the Joule heating and chemical reactions reinforce each other, which is likely the key to the ‘easy’ detonation of nitromethane.

Robust carbon-encapsulated Ni nanoparticles as high-performance electrocatalysts for the hydrogen evolution reaction in highly acidic media

The major challenges related to non-noble-metal electrocatalysts toward the hydrogen evolution reaction (HER) in an acidic environment are to overcome their low efficiency and poor stability. For this purpose, we propose a rational top-down method to construct a hybrid structure of nickel encased by a carbon shell (Ni@C) using CH4 as a carbon source and Ni wire as a sacrificing template during an electrical explosion of wire. The Ni@C nanoparticles are introduced as highly active and durable non-noble metal electrocatalysts for the HER. The optimized Ni@C (15%) core-shell catalyst (CH4/Ar = 15/85 pressure ratio) demonstrates the highest catalytic activity for the HER with an overpotential of 85 mV to drive a current density of -10 mA cm−2 and displays a low Tafel slope of 44 mV dec−1. Another virtue of Ni@C (15%) is its superior stability during an unattenuated HER chronoamperometry for over 24 h. Furthermore, it endures over 168 h submerging in 2 M H2SO4 solution without losing its catalytic activity for HER.

CYTOTOXIC PROPERTIES OF NANOSTRUCTURES BASED ON ALUMINUM OXIDE AND HYDROXIDE PHASES IN RELATION TO TUMOR CELLS

Background. Currently, the use of nanoparticles and nanostructures as components of tumor therapy is the subject of numerous scientific articles. To change the parameters of cell microenvironment in presence of nanoparticles and nanostructures is a promising approach to reducing the tumor cell viability. Aluminum hydroxides and oxides have a number of advantages over other particles due to their porous surface, low toxicity, and thermal stability.The purpose of the study was to investigate the influence of the acid-base properties of aluminum hydroxide structures with different phase composition on the tumor cell viability (Hela, mda, pymt, a549, B16F10).Material and methods. Aln/al nanoparticles were used as a precursor for obtaining structures with various phase compositions. The anoparticles were produced by electric explosion of an aluminum wire in a nitrogen atmosphere. Such nanoparticles interact with water at 60 °Ϲ, resulting in formation of porous nanostructures. They are agglomerates of nanosheets with a planar size of up to 200 nm and a thickness of 5 nm. The phase composition of the structures was varied by the calcination temperature. A change in the phase composition of nanostructures led to a change in the acid-base properties of their surface. To estimate the number of acidic and basic centers on the surface of nanostructures, the adsorption of Hammett indicators was used. The amount of adsorbed dyes was determined spectrophotometrically.Results. It was found that the differences in the acid-base characteristics of the surface of the nanostructures led to a change in their antitumor activity. Γ-al2o3 had 6.5 times more basic centers than acidic ones, which determined its ability to exhibit more pronounced antacid properties, i.e. Longer to neutralize protons secreted by tumor cells. This sample had the highest antitumor activity against all tested cell lines.Conclusion. The antitumor activity of synthesized structures was found to be related not only to an increase in the ph of the cell microenvironment, but also to the ability to maintain the alkalinity of the microenvironment for a longer time due to the adsorption of protons released by tumor cells.

Characterization of nano / micro bimodal 316L SS powder obtained by electrical explosion of wire for feedstock application in powder injection molding

Bimodal nano / micro powders are in demand in powder injection molding (PIM) and additive manufacturing (AM) technologies. Feedstocks with bimodal powder have a higher flowability, and the resulting products have a higher density.In this work, a bimodal 316L steel powder obtained by the electric explosion of a wire (EEW) was investigated. The bimodal powder is formed directly during the explosion and does not require a mixing step. The powder was obtained at different explosion energy densities. A feedstock was obtained with a powder content of 94 wt%.The powders have a different micro: nano ratio depending on the energy density. Feedstocks with these powders have different rheological behavior. The morphology and chemical composition of the powders and the homogeneity and rheological properties of feedstock with bimodal powder were studied and discussed. A comparison of feedstock properties with bimodal and micron powder is carried out.

Synthesis and characterization of carbon-coated Cu-Ni alloy nanoparticles and their application in conductive films

In this paper, an efficient fabrication route is presented for carbon-coated Cu-Ni alloy nanoparticles (Cu1-xNix@C NPs; x = 0–1.0) by means of electrical wire explosion under methane gas. The Cu-Ni binary system, which is considered to be an ideal isomorphous system, has carbon growth controllable by tuning the atomic fraction of Cu and Ni with largely different carbon solubility. As the Ni content increases, the average particle size and carbon layer thickness increase. It is notable that the carbon layer is very thin, <2 nm, regardless of the core size for pure Cu@C NPs. On the other hand, as the Ni content increases, the particle size dependence of the carbon-layer thickness becomes significant and the carbon layer is obviously tunable from amorphous to crystalline form. The high-temperature oxidation stability of Cu1-xNix@C NPs is enhanced with increasing Ni content due to the higher thermal stability of carbon layers with greater thickness and high crystallinity. The conductive films were prepared using screen-printing of paste containing Cu1-xNix@C NPs and the electrical resistivity was mapped according to the Ni content. The temperature stability of the sheet resistance and activation energy of oxidation for the conductive films increase with increasing Ni content.

Metal, Metal Composite, and Composited Nanoparticles Obtained by Electrical Explosion of Wires

Nanoparticles (NPs) possess a unique combination of physicochemical properties, which makes them promising materials for use in such fields of science and technology as materials science, biomedicine, and catalysis. This review presents data on the structural characteristics of metal, alloy, and composite NPs, as well as metals oxide, carbide, and nitride NPs, obtained by electrical explosion of wires (EEW). The main attention is paid to the relationship of the size distribution and phase composition of NPs with the EEW conditions and the parameters of the buffer medium (chemical composition, pressure) in which the explosion is performed. The analysis of the studies show that EEW makes it possible to obtain a wide range of NP-based powders.

Discharge characteristics and spatial-temporal evolution of Cu-Ni alloy wire explosion

Electrical explosion of wires (EEW) driven by pulse current can produce plasmas with high energy density, and is accompanied by electromagnetic pulses, strong shock waves, etc., therefore it is widely adopted in Z-pinch, electrothermal chemical weapons, oil and gas exploitation and other fields. Compared to pure metal, alloy has characteristics of the high resistivity, adjustable composition, and complex phase transitions. It has great potential in regulating parameters of EEW. This paper presents an experimental study on exploding Cu, Ni, and Cu-Ni alloy (constantan) wires in atmospheric air under a microsecond time-scale pulsed current. Through the diagnoses of electrical parameters and self-emission images, the discharge characteristics and spatial-temporal evolution of explosion products were obtained. Features of the alloy wire explosion in phase transition and plasma were acquired as well. Experiments revealed that in the early stage of EEW, the high resistivity of the alloy could improve the energy deposition efficiency, namely 52% for Cu, 74% for Ni, and 78% for Cu-Ni, while after the explosion, performance of the alloy wire was closer to that of the Ni wire. The initial expansion rate of the plasma channel reached 5 mm/μs level but then decayed. The expansion process of alloy wire endured longer, and the average resistivity went up slowly after the breakdown. Also, a correlation was found between plasma radiation and metal aerosol in spatial scale. Especially, the alloy aerosol has crossed striation features (10−1 mm), but it is more uniform than Cu aerosol generally.

Underwater electrical wire explosions can destroy steel plate

By using pulsed power to explode underwater wire arrays, researchers create dense water jets with extremely high energies and velocities.

Electrophoretic deposition of coatings and bulk compacts using magnesium-doped aluminum oxide nanopowders

The electrophoretic deposition (EPD) of coatings and bulk compacts in a wide range of thicknesses (from 23 to 1800 μm) from stable suspensions of a magnesium-doped aluminum oxide nanopowder with subsequent sintering of samples into dense ceramics was studied. The initial nanopowder was obtained by the method of electric explosion of an Al-Mg alloy wire with a Mg content of 1.3 wt. %. The study of the dispersion composition, kinetics of deaggregation under the ultrasonic treatment and zeta potential in the nanopowder-based suspensions was carried out. It was shown that a nearly linear increase in the deposited mass and thickness of EPD deposits occurred at a constant voltage of 20 V and an average deposition current of approximately 40 μA when the deposition time was varied from 1 to 180 min. Drying of the coatings with a thickness of less than 35 μm led to the formation of a net of small cracks, while drying of the bulk compacts with a thickness of more than 1 mm occurred without cracking. The ceramic bulk sample with a thickness of 1.2 mm and the density of 98.7% TD was successfully obtained by sintering at 1650 °C for 4 h. It was characterized by a dense grain structure with an average grain size of 5 μm and the presence of a small number of closed pores less than 1 μm in size. Sintering of ceramics was revealed to be accompanied by the formation of a MgAl2O4 crystalline spinel phase, localized mainly at grain boundaries.

One-step synthesis of FeO(OH) nanoparticles by electric explosion of iron wire underwater

In this study, we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging voltage. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), showing the presence of iron and multiple iron-based compounds oxides with contents influenced by the experimental conditions. In particular, pure FeO(OH) nanoparticles were obtained using electric explosion of iron wire with energy input of 1125 J at charging voltage of 15 kV. Analysis of discharge current and resistive voltage data indicate that the high energy input induced by strong plasma discharge at high charging voltage is a key factor to form FeO(OH). This study presents a one-step method to synthesize FeO(OH) nanoparticles using electric explosion of iron wire.

Electrical Explosion Synthesis, Oxidation and Sintering Behavior of Ti-Al Intermetallide Powders

In this research, Ti-Al powders were produced by electrical explosion of twisted titanium and aluminum wires. The resulting powders were pressed and sintered in a vacuum to obtain bulk composites. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) studies were performed to analyze synthesized powders and bulk composites. The studies carried out showed the presence of α-Ti, α2-Ti3Al, and γ-TiAl phases, which are formed by coalescence of Ti and Al clusters formed in the process of non-synchronous electrical explosion of twisted wires. Furthermore, an increase in the energy injected into the wires leads to a decrease in the content of micron particles in the powder. During sintering of pressed Ti-Al powder in the range 800–1250 °C, phase transformations occur due to the diffusion of aluminum atoms towards Ti compounds. The research findings can be used to obtain Ti-Al particles and bulk composites with a controllable phase composition.

Influence of Structure and Dispersivity of Copper on its Melting Features

The melting parameters (melting point, specific heat of fusion) of copper samples with different volume structure (fine-grained, submicrocrystalline) and dispersivity (fine powder) were explored using differential thermal analysis. It was found that change in the metal structure from bulk coarse-grained to submicrocrystalline, and to submicron powders led to depression of melting point by ~18 °C and of specific heat of fusion by ~45 % relative to the standard values. It was shown that the high-energy impact on the starting coarse-grained metal used to obtain the samples with modified structure and dispersivity (severe plastic deformation, electric explosion of thin wires) caused changes in the composition of the material. An explanation for the observed influence of structure and dispersion factors on the melting parameters has been proposed on the basis of X-ray diffraction data, electron microscopy, and model calculations.

Features of Structural-Phase Transformations during Oxidation of Metals with Bulk Submicrocrystalline Structure and Fine Metal Powders

The oxidation processes for compact and powdery samples of titanium, copper, and molybdenum with different volume structure and dispersivity were studied using thermal analysis, electron microscopy, and X-ray diffraction. It is established that producing of metals with a modified structure under conditions of high-energy impact (severe plastic deformation, electric explosion of a thin wire) in accordance with intermediate annealing leads to an increase in the content of oxygen in the form of solid solutions and oxides; the oxide component’s share, form and localization within the material depend on physicochemical properties of both metal and oxide . It is shown that the structural-phase transformations of the oxide component during heating of fine-grained metals and powders have a significant effect on the parameters of the oxidation process of such materials. The thermally induced effects in the oxygen-containing components might play a critical role for the structure stability during long-term use of such materials under cyclic thermomechanical impacts.

A novel method of processing sheet metals: Electric-pulse triggered energetic materials forming

• A novel high-velocity sheet metal forming method is proposed: ETEF. The energetic materials (EMs) were introduced into the EHF system, and the electrical explosion of metal wire ignited EMs and released energy. • The EMs under the 10 wt.%Al/90 wt.%AP conditions exhibited the highest energy release efficiency, the energy grade of EMs was determined to be 3.04 kJ/g in this work. Under discharge voltage of 3 kV, the bulging height of DP600 specimen from ETEF was increased by 162 % relative to that from EHF. • Compared with that of EHF/7 kV, the strain concentration area of the sheet under the ETEF was wider (about 60 mm). The maximum major strain and maximum thinning rate of the specimen under the 2 g/3 kV/10 wt.% Al/90 wt.% AP conditions were reduced by 10.6 % and 13.1 %, respectively. • The dynamic deformation of the DP600 specimens during ETEF were presented for the first time by LS-DYNA. The EMs were ignited by electric explosion of metal wire to realize the coupling of two kinds of energy. To improve the formability of sheet metals at room temperature and overcome the limitation of the upper limit of energy storage in electrohydraulic forming (EHF), a novel sheet metal forming is proposed: electric-pulse triggered energetic materials forming (ETEF). The power to deform a metal sheet originates from the electrical explosion of a metal wire in a liquid chamber and that releasing chemical energy from the energetic materials (EMs) being triggered. Equi-biaxial stretching tests of DP600 were carried out through ETEF with different weight ratios and changing grams under a low discharge voltage. The final profiles, strain and thickness distribution of the sheet were analyzed. The energetic materials with 10 wt.%Al/90 wt.%AP had an energy level of 3.04 kJ/g, and the bulging height of the deformed specimen was 34 mm, which was higher than the energy levels obtained under other testing conditions. Compared with that of the 7 kV specimen of the same bulging height (34 mm) obtained by EHF, the strain concentration region of the specimen processed under the 2 g/3 kV/10 wt.% Al/90 wt.%AP conditions widened by 52.5 %, and the maximum major strain and maximum thinning rates were lower by 10.6 % and 13.1 %, respectively. The dynamic deformation characteristics of the DP600 specimens during ETEF were presented for the first time by LS-DYNA. The values obtained for the DP600 sheet were as follows: maximum bulging height, 32 mm; maximum effective strain rate, 1521/s; and maximum speed, 258 m/s.

Electric explosion of wires as versatile method for antibacterial Janus-like ZnO–Ag nanoparticles preparation

Electric explosion of zinc and silver intertwined wires in an oxygen-containing atmosphere was used for the first time to produce ZnO–Ag bicomponent nanoparticles. Silver content was regulated by wire diameters. The nanoparticles were characterized by transmission electron spectroscopy, X-Ray diffraction. Optical properties of ZnO–Ag nanoparticles were studied by ultraviolet–visible spectroscopy. The phase state of nanoparticles in the range of high (12–35%) silver content has been established, which provides an increase in the photocatalytic activity in the visible spectral range. The Methylene blue degradation efficiency by ZnO-12Ag nanoparticles reached 90%, which was higher than that of ZnO nanoparticles produced by electric explosion of zinc wire. Composites had high antibacterial activity against Escherichia coli bacteria.

Synthesis of Fe/Fe3O4 core-shell nanoparticles by electrical explosion of the iron wire in an oxygen-containing atmosphere

Magnetic nanoparticles based on iron and its oxides are promising in various biomedical applications. Currently, as a rule, ferromagnetic iron oxide particles with a low specific magnetic moment are used for medical purposes. In the present work, a new method for the synthesis of magnetic nanoparticles based on the electric explosion of a Fe wire is proposed. When wires are dispersed by high current electric pulse in an inert atmosphere containing less than 5% oxygen, nanoparticles with a core-shell structure are formed, where the core is α-Fe and the shell is formed by a mixture of oxides Fe3O4 and FeO. The oxygen concentration in the buffer gas has been found to determine the size of the resulting nanoparticles, their shape, and iron content. The iron oxide shell protects the iron core from the external environment, preventing the rapid dissolution of Fe containing in the nanoparticles, in contrast to nanoparticles obtained in argon atmosphere. The specific magnetic moment of nanoparticles, depending on the content of iron oxides, varies from 90 to 180 emu/g.