Nickel Deposition Research Articles

Kinetika Leaching Ni dan Fe dari Bijih Laterit Tipe Limonite Morowali

Nickel (Ni) deposits are depleting, while demand for the metal is increasing. To address this problem, valuable metals such as Ni and Fe can be extracted from secondary sources such as limonite-type laterite ores. The goal of this study was to investigate the influence of leaching temperature on Ni and Fe recovery, as well as the best kinetic model to represent the leaching process of these metals. Temperature has a considerable impact on the leaching process of Ni and Fe. Increasing the temperature from 30 to 90 oC can increase the recovery of Ni by 50% and Fe by 70 %. Ni and Fe recoveries were highest at 93.21 % and 95 %, respectively. Kinetic analysis of the two metals' leaching processes was also performed. It was discovered that the diffusion process controls Ni leaching, which can be represented using the Zhuravlev kinetic model, whereas chemical reactions on the surface of the unreacted core controls Fe leaching. The activation energies for leaching Ni and Fe are 36.53 and 40.32 kJ/mol, respectively. 1930 exp ((-36.53 kJ/mol)/(R.T))t=[(1-X)-1/3)-1]2 is the kinetic equation for Ni leaching. The kinetic equation for Fe leaching is 3903 exp ((- 40.32 kJ/mol)/(R.T)t=1-(1-X)1/3.

Magnetoelectric effect in three-layered gradient LiNbO3/Ni/Metglas composites

The effect of annealing in a permanent magnetic field on the magnitude of magnetoelectric coefficient in three-layered gradient magnetoelectric LiNbO3/Ni/Metglas composites has been studied. A method of electrochemical nickel deposition on bidomain lithium niobate crystals has been demonstrated. We show that the optimum annealing temperature in a permanent magnetic field for the generation of the highest remanence in the Ni layer is 350 °C. The specimens annealed at this temperature exhibit the greatest shift of the magnetoelectric coefficient dependence on external magnetic field magnitude relative to the value Hdc = 0. The quasi-static magnetoelectric coefficient in the absence of an external magnetic field proves to be 1.2 V/(cm ∙ Oe). The highest magnetoelectric coefficient that has been achieved at a bending structure resonance frequency of 278 Hz proves to be 199.3 V/(cm ∙ Oe) without application of an external magnetic field. The experimental magnetoelectric coefficient figures for three-layered gradient LiNbO3/Ni/Metglas composites are not inferior to those for most magnetoelectric composite materials reported earlier.

Awaruite, a new large nickel resource. Part 2: Assessment of magnetic separation

In this work, a research study, focused on the recovery of awaruite, was conducted on a representative sample from the Baptiste deposit to evaluate magnetic separation over a range of magnetic field strengths. The Baptiste deposit is a unique nickel deposit containing awaruite, a high-density ferromagnetic nickel–iron alloy. The evaluation included semi-batch and continuous pilot scale tests, employing wet magnetic drums at two different grind sizes. The samples were characterized using techniques including chemical composition analysis, Davis tube testing, and automated mineral analysis. The results showed promising magnetic nickel recoveries, in the range of 92% to 96%. The development of the Baptiste deposit will benefit from a sound scientific understanding of the process solution.

The distribution of trace elements in sulfides and magnetite from the Jaguar hydrothermal nickel deposit: Exploring the link with IOA and IOCG deposits within the Carajás Mineral Province, Brazil

The Jaguar nickel deposit represents an important and unconventional discovery of hydrothermal Ni resources (58.9 Mt @ 0.95% Ni) associated with magnetite and apatite within the Carajás Mineral Province, Northern Brazil. The Jaguar deposit shares several similarities with iron oxide copper–gold (IOCG) deposits of the Carajás Mineral Province, especially regarding the structural control, and the hydrothermal alteration. Although IOCG and Kiruna-type iron oxide-apatite (IOA) deposits are closely associated in several geological provinces, this association has not yet been fully constrained in the Carajás Mineral Province. The Jaguar deposit occurs near mafic–ultramafic intrusions, along a regional fault zone, and is hosted either by granitic (northern portion) or felsic subvolcanic (southern portion) rocks. It is characterized by sub-vertical zones hosting a biotite-chlorite (Bt-Chl) hydrothermal alteration with ductile structures and disseminated sulfides (pyrite and millerite) and magnetite. These zones are overprinted by sulfide-magnetite-apatite-bearing breccias, which represent the main mineralization bodies. The sulfide assemblage in the mineralized zones is dominated by pyrite, pentlandite and millerite, with minor sphalerite and chalcopyrite.We have investigated the concentration of trace elements in the magnetite and sulfides from the host rocks, different alteration facies and the mineralization at the Jaguar deposit by LA-ICP-MS. Magnetite composition ranges from higher Al, Mn, Ti and V contents, for at least part of those in host rocks (granitic and felsic subvolcanic) and Bt-Chl alteration, into lower contents in the magnetite-apatite alteration, associated with the main Ni mineralization. Magnetite with higher Ti and V contents in host rocks is associated with discrete hydrothermal alteration pockets, have high Ni/Cr ratios and plot in high temperature hydrothermal fields in multi-element diagrams. Therefore, we support that these features are compatible with a hydrothermal origin. Anomalously high-Ni contents in magnetite point that the Neoarchean mafic–ultramafic layered intrusions of the Carajás Province represent potential Ni sources for hydrothermal remobilization. Anomalously high V contents in magnetite suggest lower fO2 conditions upon the formation of the deposit. The concentration of trace elements in magnetite associated with the Jaguar deposit is similar to those from other IOCG deposits from the Carajás Province (but with higher V and Ni contents), especially the Sossego mine in the Southern Copper Belt, indicating that it could represent a Ni-rich member of the regional-scale IOCG mineral system at Carajás. Pyrite and chalcopyrite have a composition similar to those from magmatic deposits, when using previously proposed discriminant diagrams, but this is also the case for other IOA and IOCG deposits. However, low PGE contents (Ru, Rh, Ir and Os) in pyrite from the Jaguar deposit support a hydrothermal origin. Our results highlight that the classifications provided by available discriminant diagrams are not unequivocal. We suggest that multi-element diagrams represent a complementary approach to binary plots and provide a more comprehensive classification for the use of indicator minerals.

The Geological Position and Minerals of Rare and Noble Metals in the Ores of the Kun-Manie Copper–Nickel Deposit (Southeastern Rim of the Siberian Craton)

The Geological Position and Minerals of Rare and Noble Metals in the Ores of the Kun-Manie Copper–Nickel Deposit (Southeastern Rim of the Siberian Craton)

GEOMORPHOLOGY AND CHARACTERISTICS OF NICKEL LATERITE IN BAINGKETE VILLAGE, MAKBON DISTRICT, SORONG REGENCY WEST PAPUA PROVINCE

Nickel deposits geologically came from weathering of abducted ultrabasic igneous rock. The rock is exposed during removal, followed by a geomorphological process that develops laterazation. Geologically the Makbon area is on the path of the Sorong horizontal fault field which has been active since the beginning of the Miocene. The dominant Sorong fault movement to the west exposed ocean floor rocks including blocks of ultrabasic rock. To determine the mineralization of nickel laterite in the Makbon area, this study combines mapping and surface geological observation methods with XRF analysis in the laboratory. The results of the study are known that the research area is composed of six land formations, namely the Makbon Fault Block Ridge, Baingkete Fault Block Ridge, Bancuh Baingkete Hills, Baingkete Bald Mountain Bancuh Hills, Makbon Fault Structure Denudation Plain, and Dore Bay Hills. Geomorphological control of the distribution of laterite nickel on steep slopes produces a thin, thickened laterite layer on the topography of the ramps. The characteristics of laterite nickel deposits in Baingkete Village are Type A deposits (Mg-Ni Silicate), on serpentinite bedrock, which consist of laterite profiles of limonite zone, saprolite zone, and bedrock zone

Physico-Chemical Properties of Zn-Ni Alloy from an Alkaline Sulphate Bath Containing Triethanolamine and Mercaptopyridine

The composition, properties and morphology of electrodeposited Zn-Ni alloy from an alkaline sulphate bath containing triethanolamine (TEA) and mercaptopyridine (MPY) have been investigated. A bath solution containing 3.5% wt. Ni content produced an alloy deposit with 12.5% wt. Ni (more noble metal) indicating preferential deposition of nickel (i.e. Regular co-deposition process). With increase in current density and the concentration of TEA, the percentage of nickel in the alloy deposit decreased. An increase in temperature, thickness and the concentration of MPY increases the percentage of nickel (more noble) in the Zn-Ni alloy deposit. CCE was decreased with current density, increased with temperature and stirring of the bath solution. Static potentials of Zn-Ni alloy were less noble to nickel and more noble to zinc. Hardness of the alloy increased with an increase in %Ni in an alloy. Fine grained deposits were observed morphologically.

KARAKTERISTIK BATUAN ASAL (BEDROCK) PEMBENTUKAN NIKEL LATERIT PADA DAERAH X DAN SEKITARNYA KABUPATEN MOROWALI UTARA SULAWESI TENGAH

Abstract
 Administratively, the research area is included in North Morowali Regency, Central Sulawesi Province, Central Java Province, which is in the 49 S zone with UTM (Universal Transverse Mercator) coordinates 9152800 – 9152800 400800 - 406800 mE with an area of ​​± 54 km2 (9 km x 6 km). ). One of the factors that influence the formation of laterite nickel deposits is the source rock. The purpose of this research is to focus on the characteristics of the original rock, namely ultramafic rock based on the intensity of serpentinization, its constituent minerals, and its relation to the laterization potential of nickel deposits in area X and its surroundings, North Morowali Regency, Central Sulawesi. The research method used is literature study, field activities (surface mapping), data processing (laboratory analysis and studio analysis), and report generation. Based on megascopic data, the research area consists of three units, namely alluvial units, peridotite rock units and limestone units. Based on petrographic analysis, the characteristics of the original rock in 10 rock samples were dominated by dunite and followed by serpentinized dunite, harzburgite, lerzolite, wehrlite, and serpentinite. The main mineral compositions in the rock are olivine, clinopyroxene, orthopyroxene, and group serpentine (antigorite, lizardite and talc). Laterite distribution in the research area is dominated by rocky laterite and laterite, with the prospect area being in the eastern part of the study area. The distribution of serpentinization zones based on the intensity level of serpentine minerals in the rock, found in the western hills is dominated by very low-medium serpentinization, while the eastern hills are dominated by low-high serpentinization. 
 Key words : Origin Rock, Laterite, North Morowali, Petrography, Serpentinization

Study of the composition and properties of the intermetallic layer of Al–Ti and Ni–Ti obtained on a titanium alloy for laser processing

The results of a study of intermetallic coatings of the Al–Ti and Ni–Ti systems obtained using the method of cold gas-dynamic spraying on a titanium alloy substrate and laser processing are presented. The precursor coating was obtained by cold spray deposition of aluminum and nickel and then it was processed by a laser. The change in the composition and properties of the coating under different laser processing modes is shown. The structure and microhardness of the coating are investigated, and the results of X-ray phase analysis are presented.

Characterization of electroless Ni-coated Fe–Co composite using powder metallurgy

AbstractThis study covers composite production and characterization of powders obtained by applying the electroless Ni coating technique to Fe–Co powders by microwave sintering technique. The physical, mechanical, and electrical properties of electroless Ni-coated Fe and Co composites samples produced in different compositions by sintering magnetic materials in a microwave oven at 1,100°C were characterized. With the electroless coating technique, a uniform nickel deposit on the Fe–Co particles was coated before sintering with the precipitation procedure. A composite consisting of metallic phase, Fe–Co, and triple additions in a Ni matrix was prepared in an argon atmosphere and sintered by microwave technique. X-ray diffraction, scanning electron microscope, and impedance phase analyzer were used to obtain structural data in the temperature range of 25–40°C and to determine magnetic and electrical properties such as dielectric and conductivity. The ferromagnetic resonance was varied between 10 Hz and 1 GHz, and measurements were made to characterize the properties of the samples. Numerical findings obtained for 25% Ni composition at 1,100°C (Fe–37.5% Co) suggest that the best conductivity and hardness are obtained by adding 25Ni at 1,100°C sintering temperature.

Electrochromic Displays via the Room-Temperature Electrochemical Oxidation of Nickel.

Electrochromism refers to the persistent and reversible change in color by applying an electric field. The phenomenon involves the insertion and extraction of electrons and ions within the active material. There is a keen interest in electrochromic (EC) materials, since they exhibit a wide range of potential applications. In recent years, transition-metal oxides have been widely investigated as EC materials due to their low power requirement, high coloration efficiency, and memory effect under an open-circuit condition. Nickel oxide (NiO), a p-type wide band gap semiconductor, exhibits attractive features such as a high color contrast ratio, good chemical stability, cost-effectiveness, and good compatibility with the cathodically coloring tungsten oxide. NiO thin films have been fabricated by various methods, but these are not cost-effective, scalable, or suitable for flexible applications. With the increasing demand for flexible and soft EC devices, it is essential to find routes to fabricate NiO thin films at lower temperatures. In this work, a NiO/Ni(OH)2-based thin EC layer on fluorine-doped tin oxide-coated glass is developed via an electroless nickel (EN) deposition route, followed by room-temperature electrochemical oxidation. The deposition time is optimized to control the film thickness. The EC performance is investigated in an aqueous alkaline electrolyte (1 M KOH) by means of cyclic voltammetry, chronoamperometry, and transmittance measurements. Both the as-deposited and annealed films, after electrochemical oxidation, exhibit excellent EC properties with an optical modulation of approximately 64% (at 550 nm) and good response times of approximately 3 s (coloration) and 14 s (bleaching). A 2 × 2 display obtained by patterning the EN deposition is also demonstrated as part of this work.

Influence of Heat Treatment on Microhardness and Surface Roughness of Electroless Ni-YSZ Composite Coating

The application of heat treatment was introduced in Ni-YSZ composite coating as the incorporation of ceramic YSZ in electroless nickel deposition is new and worth investigating. In this paper, the influence of heat treatment by varying the heating temperature and time on the electroless Ni-YSZ composite coating is investigated. The Ni-YSZ composite is deposited onto a high-speed steel substrate via electroless nickel co-deposition. YSZ powder of mixed sizes of micro- and nano-sized of the ratio of 1:1 is incorporated in the electroless deposits. The electroless Ni-YSZ composites coating was heated up to 400oC for a maximum of 2 hours. The microhardness measurements were carried out using a Vickers microhardness tester (Shimadzu) according to ISO 6507-4. The surface roughness of the coating was measured using Mitutoyo surface roughness tester SJ-301. The surface characterisation was analysed using Cambridge Stereoscan 90 Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray Analysis (EDX). The crystallographic structure of materials was analysed by X-ray diffraction (XRD) Bruker D8 Advance instrument. The microhardness and surface roughness of the coating both increase with time. The microhardness is directly proportional to the heating temperature and time and these observations are supported by the XRD analysis. The surface roughness observation is explained by the SEM micrographs.

Electrochemical deposition of nickel from local nickel sulphate solution on copper substrate

In this work, nickel was deposited on copper substrate through electrodeposition which was abstracted from local sulphate salt. Nickel deposition on copper substrate was done in both presence of vitamin C and saccharin additive. Boric oxide was used as buffering agent and pH of the solution bath was maintained through sulfuric acid and ammonium hydroxide. Round shape deposition on copper substrate was observed in the presence of vitamin C, while columnar shape particles were observed in the presence of saccharin additive. Deposition of nickel was done through sulfate bath on copper substrate. Boric acid was used as buffering agent and direct current electrolysis were conduct throughout this experimental work. pH of the solution was kept constant with the help of diluted sulfuric acid and ammonium hydroxide. The deposited nickel particles were obtained in round shape in the presence of vitamin additive, while columnar shape particles obtained in saccharin additive. The experimental conditions were optimizing to get smooth, adherent, and acid resistance surface. This research work reported that, rate of sulfate bath deposition increases lineally with increase in temperature and pH of the solution.

Innovative Processes for a Low Impact in the Electroplating of Stainless Steel

Steel is a cheap renewable material with many interesting properties but its presence in the electroplating sector is very limited due to adhesion difficulties. Stainless steel contains approximately 10.5% chromium, which forms a surface oxide layer that passivates the steel, making it resistant to corrosion [1]. It is the presence of this surface oxide film that makes it difficult to electroplate steel. The aim of electroplating steel is to refine it by depositing nobler metals of the desired color, such as ruthenium and gold.The activation of steel involves the remotion of the oxide layer. The main method of electroplating stainless steel is generally through the deposition of nickel, but the intensive use of nickel baths makes these processes inappropriate for the sustainability paths taken by the electroplating industry. Even when nickel-based galvanizing processes are not used, it is possible that steel objects do not pass the nickel release test. This is because the steel itself contains nickel, so the removal of the surface oxide layer during the electroplating process may facilitate the release of nickel.The nickel release mechanism is not yet fully clear but bring to allergenic issues in the final product [2]. We performed a systematic study electroplating various metals and alloys on steel to evaluate which one performed better as barrier against the release of nickel and shed light on this issue.The steel substrate was characterized microscopically and spectroscopically before and after the release test. The amount of nickel was evaluated in the solution that simulates human sweat to evaluate its release in µm·cm-2·week-1 according to the standard EN 1811:2015.The authors acknowledge Regione Toscana POR CreO FESR 2014-2020 – azione 1.1.5 sub-azione a1 – Bando 1 “Progetti Strategici di ricerca e sviluppo” which made possible the projects “A.C.A.L. 4.0” (CUP 3553.04032020.158000165_1385), “A.M.P.E.R.E.” (CUP 3553.04032020.158000223_1538), “GIGA 4.0” (CUP 3553.04032020.158000105_1242) and “GoodGalv” (3647.04032020.157000060).

Electrodeposition of Ni-W Alloy from Citric Acid Free Aqueous Electrolyte As a Substitute for Hard Chrome Coating and the Effect of Tungsten Content on Coating Hardness

In the industry, chrome coating is an important player in the functional layer application. Due to its high corrosion and wear resistance as well as high hardness [1], hard chrome plating is a popular choice in the automotive and aerospace industry. However, since September 2017, the application of chrome (VI) in surface treatment is banned by the European Chemical Agency (ECHA) due to chrome (VI) being toxic and environmentally hazardous [2]. Chrome (III) compound is a popular substitute for chrome (VI) due to it being less toxic compared to chrome (VI). However, chrome (III) coating has a lower corrosion resistance, and the electroplating process is more sensitive to metallic impurities.Many new innovations have since been developed such as the plasma electrolytic oxidation (PEO), extreme highspeed laser deposition (EHLA). Even established technologies such as physical vapour deposition (PVD), thermal spraying and case hardening process have tried to replace hard chrome coating with a degree of success. Admittedly, the above-mentioned technologies have their fair share of disadvantages. PEO, a green procedure [3], causes a metal substrate to develop a highly resistant oxide which is extremely strong and corrosion as well as wear resistant. The process however needs a high temperature and pressure, continuous replacement of electrolytes and consumes a great amount of power which made the process not feasible for a wide industrial application [4-6]. EHLA and thermal spraying on the other hand are restricted to rotational symmetric components. PVD is restricted to substrates that can handle high processing temperature like nitrable ferrous base materials. Lastly, case hardening processes requires long heat treatments which contribute to a higher process cost. [7]In our presentation, another alternative for chrome coating based on electrodeposition will be introduced. The element tungsten is considered in our experiments because tungsten not only has an excellent corrosion properties and high tensile strength at high temperature, but it also has a microhardness of 650 Vickers. However, it is not possible to deposit tungsten from an aqueous solution because tungstate cannot be directly reduced to metallic tungsten due to a very low overvoltage for hydrogen evolution on tungsten. Thus, an induced co-deposition mechanism is needed, and it is known that tungsten can be easily codeposited with iron group metal. [8-9]In this study a modified Watt’s bath is used as electrolyte to deposit NiW alloy. Our preliminary tests have shown that tungsten can also be deposited with nickel without the help of citric acid as complexing agent. The usage of citric acid does indeed inhibit the deposition of nickel but show no influence in the deposition of tungsten. Hence, in our study, experiments with the rotating disc electrode (RDE) will be done to see if tungsten content in the coating could be increased when the hydrodynamic and coating parameters are manipulated. The chemical composition of the layer is measured using SEM/EDX and the surface morphology is pictured using SEM. Metallographic cross-sections are made to see if there are any fissures in the layer and the hardness of the layer is measured using the microhardness test. The dependency of hardness on the tungsten content in the layer and the annealing parameter will also be shown in the presentation. XRD measurement is conducted for phase analysis and grain size calculation. Figure 1

Perspectives for Deep Eutectic Solvents and Ionic Liquid Analogues in Metal Electroplating

Here we will specifically describe the opportunities and perspectives offered by non-aqueous so-called deep eutectic solvents (DES) and ionic liquid analogues (ILA) in the materials finishing and metal electroplating industries. We will describe a range of plating and dissolution processes from anti-corrosion coatings to new battery technologies. Details will be presented of the plating and characterisation techniques using some novel in-situ methods. These include electrochemical processing and characterisation as well as a number of cutting-edge surface methodologies including acoustic resonance methods, ESR, EXAFS, atomic force microscopy, neutron scattering techniques and magnetic resonance imaging.We will describe a number of case-studies including electrolytic deposition of nickel, alloys such as Ni/Zn, and galvanic methods associated with Au and Ag coatings for the electronics industry. 1, 2, 3 In all these studies we have focused on a combination of fundamental chemical, electrochemical, structural and spectroscopic studies, maintaining close links with industrial partners through collaboration and scale-up trials.We will include very recent updates and future prospects on the use of ILA's in energy storage vectors such as Al secondary batteries. We will describe the advantages and drawbacks of DES and ILA systems in terms of functionality, sustainability and economic cost.

CORROSION RESISTANCE OF GALVANIC NICKEL DEPOSITS AND ELECTROCHEMICAL ACTIVITY OF THEIR CORROSION PRODUCTS

Background. Bright galvanic nickel coatings, with high sulphur content, are less corrosion resistant than matte. Bright nickel coatings are particularly susceptible to corrosion damage in conditions that simulate tropical humid climates and are characterized by the presence of acetic acid vapours. Objective. The purpose of the paper is to investigate: corrosion resistance of galvanic nickel deposits in concentrated acetic acid and its vapours, electrochemical activity of sulphide-containing corrosion products of bright nickel coatings. Methods. Potentiodynamic and cyclic volt-amperometry have been used to study the electrochemical activity of galvanic nickel deposits and their corrosion products. The corrosion rate of galvanic nickel deposits has been determined by gravimetric method. Investigation of surface morphology and composition of galvanic deposits were performed using scanning electron microscopy and X-ray fluorescence analysis. Results.The increased electrochemical activity of sulphide corrosion products of bright nickel coatings is evidenced by an order of magnitude higher cathodic current densities of CVA curves obtained in acetate buffer solutions, in comparison with bright and matte nickel galvanic deposits. It has been shown that at the deposition of sulphide corrosion products of bright nickel coatings on matte nickel foil the corrosion rate of last one increase at the exposition in concentrated acetic acid and its vapours. Conclusions. Significant intensifying effect of sulphur on the corrosion of galvanic nickel deposits in concentrated acetic acid and its vapours has been established. In particular, this can be explained by the decomposition of nickel sulphide (which incorporates in the coating) in acetic acid. Sulphur in the oxidation state (-2) interacts with passive oxide coatings to form an adsorbed monolayer, which leads to the transition of nickel to the active state. Further research will focus on a deeper study of the electrochemical properties of corrosion products of bright nickel coatings.

Electrodeposition of polyfunctional Ni coatings from deep eutectic solvent based on choline chloride and lactic acid

The process of electrodeposition of nickel coatings from electrolytes based on a deep eutectic solvent (DES) mixture of choline chloride and lactic acid with a molar ratio of 1:3 was studied. The physicochemical properties and characteristics of DES, namely, con­ductivity, FT-IR and NMR analysis were determined. FT-IR results confirmed that H-bonds occurring between two components in DES were the main force leading to the eutectic formation. Electrochemical techniques were used to characterize the deposition process and scanning electron microscopy was used to study the deposit morphology. Based on polarization measurements, it has been found that at NiCl2·6H2O content of 1.14 M and a temperature of 75 °C, the limiting current density of nickel electrodeposition was near 2 A dm-2. The polarization of the cathodic nickel deposition varied within -0.63 to 1.1 V at current density of 0.25 A dm-2 It has been shown that an increase of water content in the electrolyte does not significantly affect the current efficiency of the nickel electrodeposition process, which was in a range 85-93 %. However, the increase in water content contributes to the increase of heterogeneity and crystal grains size distribution of galvanic deposits. The established values of the Wagner number indicate the predominance of the primary current density distribution in the process of electrodeposition of nickel coatings. Galvanic coatings possess a highly developed nanostructured surface, exhibit increased capillary properties, and can be used as electrode materials for the process of electrolysis of water.

Assessment of a Modified Hydrocyclone with Ultrasonic Assistance for Nickel Powder Electrochemical Production

An electrochemical reactor based on a modified hydrocyclone with ultrasonic assistance is examined with the purpose of analyzing the continuous production of nickel powder from dilute solutions simulating industrial wastewaters containing nickel. Under operating conditions, nickel deposition takes place under mass-transfer control and the helical flow inside the reactor generates a high mass-transfer coefficient, thus improving the removal of metal ions. The application of ultrasound is crucial for the detachment of the electrodeposited nickel, which allows its recovery as a metal powder. The best result was achieved at a current density of 5368 A m–2 and 60 °C yielding a nickel powder fraction obtained from the spigot of the device higher than 90%. The gravimetric current efficiency and the specific energy consumption were 33.4% and 23.8 kW h kg–1, respectively, for an experiment lasting 13 min. The nickel particles are of high purity and dendritic nature with an average size of 22.9 μm.

On-Demand Metallization System Using Micro-Plasma Bubbles.

3D wiring technology is required for the integration of micro–nano devices on various 3D surfaces. However, current wiring technologies cannot be adapted to a variety of materials and surfaces. Here, we propose a new metal deposition method using only a micro-plasma bubble injector and a metal ion solution. Micro-plasma bubbles were generated on demand using pulses, and the localized reaction field enables metal deposition independent of the substrate. Three different modes of micro-plasma bubble generation were created depending on the power supply conditions and mode suitable for metal deposition. Furthermore, using a mode in which one bubble was generated for all pulses among the three modes, copper deposition on dry/wet materials, such as chicken tissue and glass substrates, was achieved. In addition, metal deposition of copper, nickel, chromium, cobalt, and zinc was achieved by simply changing the metal ion solution. Finally, patterning on glass and epoxy resin was performed. Notably, the proposed metal deposition method is conductivity independent. The proposed method is a starting point for 3D wiring of wet materials, which is difficult with existing technologies. Our complete system makes it possible to directly attach sensors and actuators to living organisms and robots, for example, and contribute to soft robotics and biomimetics.