Electrolytic Powder Research Articles

On The Potential Use of Copper-Modified Geopolymer Incorporating Lead-Smelter Slag for Thermal Energy Storage

Thermal energy storage (TES) system has been widely employed in concentrated solar power (CSP) plants to ensure the system efficiency. With excellent thermal characteristics, electrolytic copper powder (ECP), graphene oxide (GO) and lead-smelter slag (LSS) aggregate – a mining waste material, have been utilised in this study, aiming to fabricate metallurgical geopolymer material as a storage medium in the TES system. This paper investigated the effect of ECP contents (0, 5%, 10%, 15%, 20%) on the strength, specific heat, thermal conductivity and thermal stability of GO-engineered geopolymer mixes incorporating LSS aggregate. With 10% ECP inclusion, the flow rate and compressive strength improved significantly. Increasing ECP content improved the thermal conductivity but reduce specific heat of geopolymers. The results revealed that ECP was a promising component to be incorporated into geopolymer to enhance its physio-mechanical characteristics and thermal stability. The combination of ECP, GO and LSS to produce geopolymer materials for TES system can provide an eco-friendly solution to the CSP plants and the industry waste recovery.

An Electrolytic Elemental Iron Powder Effectively Regenerates Hemoglobin in Anemic Rats and Is Relatively Well Absorbed When Compared to Ferrous Sulfate Monohydrate.

Elemental iron powders are used as food fortificants to reduce the incidence of iron deficiency anemia. However, many commercially available iron powders are relatively untested in vivo. The purpose of this study was to determine the hemoglobin regeneration efficiency (HRE) and relative iron bioavailability (RBV) of an electrolytic elemental iron powder (EIP), by treating anemic rats with 14 d iron repletion diets fortified with four different concentrations (12, 24, 36, or 48 mg iron/kg diet) of EIP and bakery-grade ferrous sulfate monohydrate (FS; FeSO4•H2O), or no added iron (control); n = 9-12/group. The HRE of FS was significantly higher (p ≤ 0.05) than EIP at each concentration of dietary iron tested. For EIP, the HREs (ratios) of diets containing 12, 24, 36, and 48 mg iron/kg were 0.356, 0.205, 0.197, and 0.163, respectively. For both EIP and FS, HRE was inversely associated with increasing dietary iron. The RBVs (%) of iron from EIP in diets at 12, 24, 36, and 48 mg iron/kg as compared to FS were 64.5, 59.1, 50.6, and 54.3%, respectively. Overall, findings show that at the concentrations of iron tested, EIP has RBVs greater than 50% and is an effective fortification agent to replenish hemoglobin and correct iron deficiency anemia.

RETRACTED: Vorotilo et al. Manufacturing of Conductive, Wear-Resistant Nanoreinforced Cu-Ti Alloys Using Partially Oxidized Electrolytic Copper Powder. Nanomaterials 2020, 10, 1261.

The Nanomaterials Editorial Office retracts the article, "Manufacturing of Conductive, Wear-Resistant Nanoreinforced Cu-Ti Alloys Using Partially Oxidized Electrolytic Copper Powder" [...].

Analysis of the technology of electrochemical production of hafnium

The paper analyzes promising industrial processes for obtaining electrolytic hafnium powder. It is shown that extraction and iodide refining are the main processes used to purify hafnium from impurities, achieving both reactor-grade and high purity. The conducted studies have demonstrated the possibility of creating an alternative, more economical, and environmentally safe technology for hafnium recovery, compared to the current magnesium-thermal method. Production of reactor hafnium by electrolysis from molten electrolyte K2HfF6–KCl–KF is possible due to obtaining hafnium oxynitrate salt of nuclear purity and the creation of a hermetic electrolyzer. It is shown that the process of electrolysis leads to the accumulation of potassium fluoride in the electrolyte and requires its periodic draining with deterioration of technological indicators associated with increased recycling of the electrolyte. It was found that along with hafnium, metallic potassium is released on the cathode, which additionally worsens the technical and economic indicators of production. Sealing the electrolyzer makes it possible to create an overpressure of anode gas and determine its quantitative and chemical composition. Processing hafnium cathode sludge with potassium carbonate solution preserves the potassium cycle in the system and eliminates the effluents generated by ammonium carbonate.

Simple Preparation of Yttria‐Stabilized Zirconia Powders by Plasma Discharge Electrolysis in Nitrate Solution

Yttria‐stabilized zirconia (YSZ) powder is widely used in battery and thermal barrier coatings. This article reports a method of preparing YSZ powder using plasma in air atmosphere at room temperature in 0.34 M ZrO(NO3)2–0.06 M Y(NO3)3 solution. Diverse characterization techniques are utilized to examine the morphology and composition of synthesized powders. Electrolytic green powder consists mainly of hydroxide, which is annealed to form a well‐crystallized YSZ oxide powder with coexisting tetragonal and cubic phases. The green powder is composed of micrometer‐sized particles, with a particle size distribution (D50) of 51.90 μm. The molar ratio of Y to Zr is 2.84:1. The YSZ powder is finer (D50 is 5.80 μm) with irregular nanoparticles aggregating together, and the molar ratio of Y to Zr is 2.57:1. Hydroxyl radicals (OH·) and hydrogen radicals (H·) are found in the flame during discharge electrolysis, and the main formation reactions of the powders by this process are H2O + 2e− → H2↑ + 2OH−; Zr4+ + 4OH− + nH2O → Zr(OH)4·nH2O↓; and Y3+ + 3OH− + nH2O → Y(OH)3·nH2O↓. The conductivity of electrolyte sintered by YSZ powders increases with rising temperature, reaching 0.038S cm−1 at 1000 °C.

Influence of copper salts on the physical and mechanical properties of copper–graphite composite materials

We investigated composite materials based on electrolytic copper powder containing 1 and 5 wt. % powder of colloidal graphite the addition of trace amounts of copper sulfate and acetate. The materials were obtained through double cold pressing in a mold at a pressure of 600 MPa, intermediate sintering (annealing) in hydrogen at a temperature of 870 °C, and final sintering in vacuum at the copper premelting temperature. To analyze the influence of copper salts on the density, porosity, electrical resistivity, and strength of copper–graphite composite materials, we employed X-ray phase analysis, scanning electron microscopy, conducted strength tests in three-point bending, and determined electrical resistivity. We established that higher graphite content results in increased porosity and electrical resistivity of composite materials, along with decreased strength. In the materials containing copper sulfate, copper is reduced from the salt in the form of nanodispersed particles on the surfaces and inside graphite flakes, leading to a decrease in electrical resistivity compared to copper–graphite composites without salt additives. When copper acetate was added to the composite material, copper is reduced from the salt mainly on the surfaces of graphite particles in the form of microdispersed particles and their aggregations, as the copper acetate solution does not wet the graphite. In this case, the electrical resistivity was somewhat higher than that of the composite with sulfate but lower than that of the material without salts. The bending strength of the studied materials decreased as salts were introduced due to increased porosity and emerging defects in the crystal structure of graphite during its intercalation with copper.

On the formation of dendritic iron from alkaline electrochemical reduction of iron oxide prepared for metal fuel applications

Low-temperature electrochemical reduction (electroreduction) of iron oxides is a promising alternative to the conventional methods for iron production due to its CO2-free operation and relatively low energy consumption. In this work, we demonstrate a novel approach for electrochemical iron production by promoting the formation of dendritic structures during iron electrodeposition, which facilitates the easy harvesting of deposits in powder form. Experiments were conducted using a single pair of parallel plate electrodes, immersed in a mixture of hematite (Fe2O3) powder and aqueous alkaline (NaOH) slurry. The effects of current density, Fe2O3 mass fraction, temperature, and powder size on current efficiency and deposit morphology are investigated. A large quantity of dendritic iron structures is observed when experiments are carried out without stirring and/or applying heat from a heating plate. This condition suggests temperature and (ion/species) concentration gradients in the system. The dendrites are mainly deposited on the cathode's sides, corners, and edges. Different deposits and dendritic structures (compact layer deposit, moss-like deposit, deposit with whisker-like dendrites, and deposit with crystal-like dendrites) are observed as operating conditions change. Overall, a cathodic deposition of metallic iron with a high Faradaic efficiency (≥90 %) is successfully accomplished. The present findings provide new insights into the production of electrolytic iron powder and its future use as a carbon neutral and sustainable fuel/energy carrier.

Electromagnetic Characteristics and Microwave Absorbing Properties of a Novel Stainless Steel Powder

In order to solve the problem of insufficient oxidation resistance and corrosion resistance of magnetic metal absorbent represented by carbonyl iron powder, a wave absorbing composite material which consists of different filling mass proportions of the atomized electrolytic stainless steel powder and paraffin wax is investigated. The electromagnetic (EM) characteristics and absorbing performance of the proposed composite material were tested with Agilent N5234A vector network analyzer in a frequency range of 2–18GHz. The experimental results show that the real and imaginary parts of the dielectric permittivity of stainless steel powder/paraffin composites will increase with the filling mass fraction in the test frequency band, while the real part of the permeability [Formula: see text] decreases with the increase of the mass fraction, and the imaginary part [Formula: see text] increases with the increase of the mass fraction. At a thickness of 3 mm, with the filling mass fraction increasing from 20 wt.% to 60 wt.%, the peak frequency of reflection loss (RL) moves to low frequency from 17.92 GHz to 16 GHz. Meanwhile, the minimum reflection loss (RL[Formula: see text]) also shows a downward trend, and the RL[Formula: see text] value with a filling mass fraction of 60 wt.% is −8.93[Formula: see text]dB. It can be seen that stainless steel powder shows good microwave absorbing performance, and it has excellent anti-oxidation, and anti-corrosion properties. Based on the excellent performance of stainless steel powder, its absorption performance is expected to be further improved through multi-layer optimization design, so as to meet the needs of electromagnetic protection in harsh environments.

Influence of rare earth element la on the performance of copper-based composites

Copper-based composites with La contents of 0.02 wt%, 0.04 wt%, 0.06 wt%, and 0.08 wt% are prepared by spark plasma sintering using the rare earth element La and electrolytic Cu powder as raw materials. The influence of the La mass fraction on the properties of Cu-La relative to copper-based composites are explored by observing the microstructure and testing the density, hardness, and electrical conductivity. The results show that after La is added to Cu via spark plasma sintering, the originally arbitrarily oriented grains in pure copper are gradually adjusted to a preferred orientation. When 0.04 wt% La is added, the degree of preferred orientation in the copper-based composites increases. The strengthening mechanisms of La for copper-based composites are grain refinement strengthening, dispersion strengthening, solid solution strengthening and second phase strengthening. With increasing La addition, the hardness values of the copper-based composites increase: from 45.4 HV to 57 HV, and the tensile strength up to 215 MPa. When 0.04 wt% is added, the conductivity reaches the highest value of 88.2 IACS%. However, the addition of excessive La leads to excessive formation of the Cu6-La phase, which leads to an increase in the mechanical properties of copper-based composites but a decrease in the conductivity.

Study on Magnetic Properties of Toroidal Cores Composed by Electrolytic Iron Powder With Different Shapes

Study on Magnetic Properties of Toroidal Cores Composed by Electrolytic Iron Powder With Different Shapes

Mechanical and morphological analysis of laser transmission welded dissimilar plastics using metal absorber

This study aims to investigate the laser transmission welding (LTW) of polystyrene and polycarbonate using an electrolytic iron powder absorber. For this purpose, the experiments are performed to explore the effect of laser power and scan speed on the weld strength and bond morphology. The lap shear tests are conducted to obtain the breaking force and ductility of the welded joints. The fractured surface and cross-sections are analyzed by scanning electron and optical microscopy to investigate the bond morphology and bonding mechanism of the weldments. The results show that laser power and scan speed significantly affect the weld strength and ductility of the joints. The optical and scanning electron micrographs clarify that mechanical anchoring of iron particles, polymeric interdiffusion, and small bubbles enhance the bond strength but thermal degradation, burning, and large bubbles negatively affect the bonding.

YÜKSEK ENERJİLİ ÖĞÜTME İLE ÜRETİLEN Al2O3 TAKVİYELİ CU KOMPOZİTLERDE PARÇACIK BOYUTUNUN ETKİSİ

Production of copper (Cu) composites with a reinforced Cu matrix using mechanical alloying with Aluminum oxide (Al2O3) particles of different sizes was achieved using high-energy ball milling procedure. The initial materials consisted of inert gas-atomized spherical electrolytic Cu powders containing 0.5 wt. % commercial Al2O3 powders, with particle sizes ranging from 10 µm to 1 µm. Cu powders with different particle sizes of Al2O3 were high-energy ball milled at 500 rpm for 3 hours to attain a consistent distribution of Al2O3 throughout in the Cu matrix. The powders that were high-energy ball milled were then subjected to cold-pressing at 500 MPa and isothermally sintered for 1.5 hours at 880°C in an Ar atmosphere. The fabricated copper composite materials were characterized using X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDXS), density and macrohardness tests. The wear properties and mechanism were investigated through tribological pin-on-disc experiments, which revealed that the reinforcing effect was more significant when finely dispersed Al2O3 particles were combined into the Cu matrix compared to coarse Al2O3 particles.

MICROSTRUCTURE OF A CrSi2 TRANSITION LAYER PRODUCED BY HOT PRESSING OF Cr AND Si

Hot pressing of a Si single crystal in the bulk of electrolytic Cr powder at 1213 K, with subsequent annealing in air, leads to the formation of an intermediate polycrystalline silicide layer at the interface between the initial components. The phase composition and microstructure of the transition layer and its vicinity were investigated by scanning electron microscopy, X-ray energy-dispersive microanalysis, and electron backscatter diffraction. The transition layer has a crystal structure of the hexagonal phase of chromium disilicide (sp. gr. P6222). An additional annealing up to 120 h leads to insignificant recrystallization of small grains into larger ones.

EFFECT OF PARTICLE SHAPE AND SIZE OF COPPER POWDERS ON THE PROPERTIES OF SINTERED PARTS

The particle shape and size of the starting powders represent the most important physical properties, on which the quality of the compacts and final sintered products depends. Two types of powder were analyzed in the paper - electrolytic copper powder with a dendritic particle shape and water-atomized copper powder with an irregular particle shape. The starting powders were sieved through a sieve system with openings of 45 μm, 80 μm, and 120 μm. The characterization of the obtained fractions of both powders was performed by determining the shape and dimensions of the particles using SEM microscopy in combination with ImageJ software, and the apparent density and flow rate were determined using the Hall flowmeter funnel. Pressing of each powder fraction was done using a pressure of 600 MPa. The compacts were further sintered at 1000°C for 2 hours to obtain the final sintered parts. After sintering, their density, hardness, and electrical conductivity were determined and their microstructure was analyzed. The results indicate a great influence of the characteristics of the starting powders on the properties of the final parts obtained by the powder metallurgy route. The particle shape of the powders had a more pronounced influence compared to the particle size.

Influence of Feedstock in the Formation Mechanism of Cold-Sprayed Copper Coatings

The aim of this article is to investigate the characterizations and formation mechanisms of cold-sprayed coatings using gas-atomized and electrolytic powders. The study highlights the importance of reaching the particles’ critical velocity for optimal deposition. The main findings reveal that the morphology and stacking conditions of the coatings have a significant impact on their mechanical properties. Coatings made with gas-atomized powders exhibited noticeable pores and higher plastic deformation, while electrolytic powder coatings had greater density and smoother interfaces with the substrate. Adhesion strength relied on the physical bonding resulting from the plastic deformation energy between the spraying powders and the substrate. Gas-atomized powders showed higher adhesion compared to electrolytic powders, with dendritic powders resulting in lower adhesion due to dispersed impact force. The interaction between thermal and kinetic energy during the cold spraying process facilitated plastic deformation and particle deposition by softening and eroding the substrate surface. Insufficient plastic deformation with dendritic powders led to incomplete overlap, pore formation at the interface, and the persistence of the oxide layer along powder boundaries. Overall, these findings provide valuable insights into the influence of powder properties on coating morphology, adhesion strength, and overall performance, contributing to the understanding and optimization of cold spray processes.

Tribological behavior of sintered electrolytic iron‐zinc stearate added compacts

AbstractPowder metallurgy is an effective method to give near net shape to powder particles. In this paper, the influence of powder particle size, lubricant and compaction load on hardness and wear loss has been investigated as it influences the compact. Electrolytic iron powder (250 mesh to 300 mesh and 300 mesh to 350 mesh) with zinc stearate (0 weight % to 2 weight %) was used for preparing the samples. Green samples were prepared by cold compaction process at different loads (400 kN, 450 kN and 500 kN). Pre‐sintering was done at 550 °C. Taguchi′s (L18) mixed level model was used to develop the regression equation for hardness and wear loss. The maximum hardness of 79 HRB was achieved with 300 mesh to 350 mesh particle size and 500 kN compaction load. Minimum wear volume loss was observed with samples having composition of 250 mesh to 300 mesh size electrolytic iron powder at 500 kN compaction load and 1 weight % lubricant content.

ОПРЕДЕЛЕНИЕ УДЕЛЬНОЙ ПОВЕРХНОСТИ ПОРОШКОВ ЦИРКОНИЯ МЕТОДОМ НИЗКОТЕМПЕРАТУРНОЙ АДСОРБЦИИ АЗОТА

The work is devoted to determination of the specific surface of fine-dispersed zirconium powders of different producers by low-temperature nitrogen adsorption method using modern analytical equipment. Sodium-reduced zirconium powders of two different productions, as well as coarse electrolytic zirconium powder after its grinding by hydride technology, were researched in the present work. Consequently the values of the specific surface of the studied zirconium powders by the BET method were obtained, and features of such measurements by “Sorbtometr-M002” evaluator for the specified materials were noted.

Laser transmission welding of polycarbonate sheets using electrolytic iron powder absorber

This paper presents Laser Transmission Welding (LTW) of polycarbonate sheets using electrolytic iron powder as an absorber to obtain a clean and high-strength joint without any gap between the sheets. Surface temperature is measured to analyze the bubble morphology and relate them with the heat absorbed at the interface. The lap shear test is performed to evaluate the weld strength, and fracture modes of the welded joints. The results show that maximum weld strength is achieved with smaller bubbles. Scanning electron microscope (SEM) micrograph of the fractured surface shows micro-fibrils at the inter-bubble space, enhancing the weld strength. The iron particles present inside the bubble increase the size of the bubbles, and the presence of cleavage facets reveals the brittle failure of the joint. The weld joints are fractured mainly by interfacial and substrate fractures. The optimum process parameters are obtained using a genetic algorithm (GA), and the confirmation test shows an improvement of 36.32 % in weld strength compared with Taguchi parameters.

Mechanism of bonding during laser transmission welding using EIP absorber

ABSTRACT This paper aims to investigate the bonding mechanism during laser transmission welding of polycarbonate sheets using an electrolytic iron powder (EIP) absorber. The experiments are performed at different scan speeds and laser powers. The mechanical strength is determined by the lap shear test. The influence of line energy, interface temperature, and absorptivity on weld strength is discussed. The weld characteristics, bond morphology, and elemental distribution at the cross-section and fracture interface of the welded samples are analyzed. The results show that the maximum breaking strength of 1180 N is obtained at the 400 mm/min scan speed and 100 W laser power. The iron particles are observed mechanically interlocked at the lowest line energy with partial chemical bonding. However, the chain diffusion and chemical bonding have been increased with line energy. Thermal degradation and burning of the polycarbonate at the interface restrict the bonding and reduces the weld strength.

Peculiarities of Partial and Joint Electroreduction of Carbon and Tungsten Oxyanions in Chloride Melt

High-temperature electrochemical synthesis (HTES) in molten salts allows one to produce a wide range of interesting in the application terms chemicals: single-phase carbon nanomaterials of various structures and morphologies, as well as carbides, borides, and silicides of refractory metals [1]. A necessary condition for the successful implementation of the synthesis is a detailed study of the electrochemical behavior of the synthesis precursors - compounds of carbon and refractory metal.This work presents the results of studies on the mechanism of carbon and tungsten electrodeposition reactions from their oxide compounds (СО2; Li2СО3; Na2WO4: Na2W2O7; Na3WO3F3) in their partial and joint presence in a chloride melt. The possibility of controlling the mechanisms of electrode processes by changing the acid-base properties of melts is shown.The research algorithm was as follows. At the first stage, a thermodynamic analysis of possible pathways for the electroreduction of precursors and the choice of optimal systems and conditions for the synthesis were carried out. The next step was a voltammetric study of the electrochemical behavior (partial and joint) of synthesis precursors and the establishment of the electrode processes mechanism. After analysis of the obtained results, electrolyzes were performed in potentio- and galvanostatic modes to obtain phases of carbon, tungsten (partial reduction of precursors) and tungsten carbides (joint reduction of precursors) of various compositions. Finally, the optimal synthesis conditions were determined.Based on the analysis of thermodynamic calculations and published data, we have chosen CO2 and Li2CO3 compounds as carbon precursors, and Na2WO4, Na2W2O7, Na3WO3F3 as tungsten precursors. An equimolar mixture of NaCl and KCl was chosen as the supporting electrolyte, since the cathodic decomposition potentials of NaCl and KCl are more negative than the potentials of carbon and tungsten evolution. In addition, these chlorides are cheap and highly water-soluble salts that simplify the washing of the final product. The optimum temperature is 750 °C.For the synthesis of tungsten carbides, the following 7 compositions of electrolytic baths were chosen: (1) Na,K|Cl – Na2WO4 – CO2; (2) Na,K|Cl – Na2WO4 – NaPO3 - CO2; (3) Na,K|Cl – Na2WO4 – MgCl2 - CO2; (4) Na,K|Cl – Na2W2O7 – CO2; (5) Na,K|Cl – Na2W2O7 – Li2CO3; (6) Na,K|Cl – Na2W2O7 – Li2CO3 – CO2; (7) Na,K|Cl – Na3WO3F3 – CO2.The partial electrochemical reduction of the synthesis precursors (СО2; Li2CO3; Na2WO4; Na2WO4 – xMgCl2; Na2WO4 – xNaPO3; Na2W2O7; Na3WO3F3) in a chloride melt NaCl-KCl (1:1) was studied by cyclic voltammetry at different depolarizer concentrations, potential scan rates (0.02-10 Vs-1), reverse potentials and gaseous media in the cell.Based on the cycle voltammogram diagnostics and analysis of the products obtained by the potentiostatic electrolysis mode, the mechanisms of electrode reactions are proposed and the areas of potentials and current densities of the carbon and tungsten deposition are determined. The data obtained made it possible to purposefully select the concentrations of precursors for the electrochemical synthesis of tungsten carbides.A voltammetric study of the joint deposition of tungsten and carbon was carried out. The synthesis of nano-sized powders of carbon, tungsten, tungsten carbides of various compositions and structures (C; W; W|W2C|; W|W2C|WC|; W2C|WC; WC|C) has been implemented. The properties of electrolytic products have been studied by XRD, SEM, BET, and Raman spectroscopy. The influence of the synthesis parameters and conditions on their phase composition, morphological and structural features has been established.The electroreduction of CO2 and Li2CO3 to carbon in molten chlorides can be taken as the basis of high-temperature electrochemical synthesis of various carbonaceous nano-scaled inorganic materials: carbon films and powders of different structures and morphology (carbon nanofibres; nanotubes, graphene oxide, amorphous carbon). Joint electroreduction of CO2 and Li2CO3 with various tungsten oxyanions makes it possible to obtain a whole range of composite electrolytic materials based on tungsten carbides. The morphology and properties of the obtained products can be changed cardinally depending on the nature of the chosen precursors and synthesis conditions. Tungsten carbides have an average particle size of ~ 10 – 30 nm and consist of hollow mesoporous spherical structures with a specific surface area of ~140 m2g-1.The electroreduction of carbon and tungsten anions in molten salts presented in this work providing a promising route for the synthesis of various carbonaceous materials with great application opportunity. It was shown that the use of obtained electrolytic nano-sized powder composites WC|C as cathode material for the hydrogen evolution in sulfuric acid solutions is to be promising.[1] Shapoval VI, Malyshev VV, Novoselova IA, Kushkhov KhB (1995) Modern problems of HTES of transition metal compounds. Russ Chem Rev 64:125–132.