Crystal Nickel Research Articles

Homogeneous Crystallization of Nickel as Ni₃S₄ in a Fluidized Bed Reactor with Supersaturation Control

This study investigates the recovery of nickel sulfide (NiS) using fluidized bed homogeneous crystallization (FBHC), emphasizing the process from nucleation to crystallization. Sludge production in conventional chemical precipitation becomes a drawback in treating wastewater economically and efficiently. FBHC offers a promising alternative by minimizing sludge generation. The study examines various operational parameters, including hydraulic retention times (HRT), reflux ratio (R), initial nickel concentration, and static bed height (SBH), to optimize NiS recovery. Results show that FBHC achieves high total removal efficiency (TR) and crystallization ratio (CR), under the optimum condition of HRT = 15min, R = 8.3, initial nickel concentration = 147mg/L, and SBH = 35cm. The agglomeration of Ni(OH)2 was found to be crucial for the crystal growth during the surface oxidation of Ni3S4. This technological approach to wastewater treatment offers highly efficient heavy metal removal from wastewater.

Enhanced Nickel Recovery from Mixed Hydroxide Precipitate Through Selective Leaching with KMnO4 Oxidant

Mixed Hydroxide Precipitate (MHP), a metal precipitate with the dominant nickel and cobalt content in hydroxide compounds, can be leached as a lithium battery precursor. In this study, KMnO4 was used as an oxidant agent to increase the solubility of Ni and Co. The variation of the sulfuric acid concentration (0.5 - 1.5 M) as a leachate reagent, the concentration of KMnO4 (2.5 - 7.5 g/L), and the selective leaching temperature (60 - 80°C) were investigated. Solvent extraction using CYANEX 272 and D2EHPA was performed to separate the Ni, Co, and Mn. Atomic Absorption Spectrometry (AAS), Inductively coupled plasma mass (ICP-OES), and X-ray Fluorescence (XRF) were used to analyze the chemical compositions. At the same time, crystallographic analysis was observed with X-Ray Diffraction. It was observed that potassium permanganate increased the dissolution of Ni and Co to 91.3% and 85.4% but decreased the dissolution of Mn (37.53%) under the following conditions: 1.75 M sulfuric acid, 7.5 g/L potassium permanganate, and 60°C temperature. High purity of nickel crystal (99.64%) was observed with spontaneous nucleation due to the supersaturated nickel solution after solvent extraction with CYANEX 272. Thus, using permanganate ion as selective leaching of Ni and Co from Mn is promising.

Negative Creep of Single Crystals of Nickel–Based Superalloys

Negative Creep of Single Crystals of Nickel–Based Superalloys

Interaction of Valine with Biometal Chlorides in an Aqueous Environment at 25°C

Research in medical biology and pharmacology can expand understanding of the interactions of biometals with amino acids, which are key components of biological systems. This may lead to the development of new complexes that can be used in medicine, for example, to develop new drugs with antimicrobial activity or to maintain metabolic balance in the body. Research purpose:obtaining complex compounds of biometals, cobalt chloride, nickel chloride and manganese chloride with the amino acid valine, as well as the study of their physicochemical and biological properties. For the analysis, the Kjeldahl method was used to determine the nitrogen content. The composition of the formed crystals was analyzed by IR spectroscopy. The structure and shape of cobalt, nickel and manganese crystals were determined using a microscope. The identity of the obtained compounds was confirmed by IR spectroscopy and microscopic analyses. We can conclude that valine in the complex is coordinated to metal ions through the oxygen atoms of the carboxyl and nitrogen groups of the amine groups.

Interaction of Threonine with Biometal Chlorides in an Aqueous Environment at 25°C

The method for the synthesis of complexes with transition group biometal salts with the amino acid threonine includes improvement of reaction conditions, selection of reagents and analytical methods to confirm the formation of complexes. Research purpose: obtaining complex compounds of biometals, cobalt chloride, nickel chloride and manganese chloride with the amino acid threonine, as well as the study of their physicochemical and biological properties. In the synthesis of complex compounds, the preparative method was used. Compositions of the formed crystals were analyzed by IR spectroscopy. The structure and shape of cobalt, nickel and manganese crystals were determined using a microscope. The identity of the obtained compounds was confirmed by IR spectroscopy and microscopic analyses. We can conclude that threonine in the complex is coordinated to metal ions through the oxygen atoms of the carboxyl and nitrogen groups of the amine groups.

Effect of Magnetic Field on Maskless Localized Electrodepositing Three-Dimensional Microstructure of Nano Nickel Crystals.

In the intricate process of maskless localized electrodeposition (MLED) for fabricating three-dimensional microstructures, specifically nickel micro-columns with an aspect ratio of 7:1, magnetic fields of defined strength were employed, oriented both parallel and anti-parallel to the electric field. The aim was to achieve nanocrystalline microstructures and elevated deposition rates. A detailed comparative analysis was conducted to examine the volumetric deposition rate, surface morphology, and grain size of the MLED nickel crystal 3D microstructures, both in the absence and presence of the two magnetic field directions, facilitated by a self-assembled experimental setup. The results indicate that the anti-parallel magnetic field significantly boosts the volumetric deposition rate to a notable 19,050.65 μm3/s and refines the grain size, achieving an average size of 24.82 nm. Conversely, the parallel magnetic field is found to enhance the surface morphology of the MLED nickel crystal 3D microstructure.

Особенности термореакционной способности электролитических никелевых покрытий с различной морфологией поверхности

Nickel coatings consisting of oriented structures have unique catalytic properties. However, the temperature range for the use of such coatings is not determined, and a comprehensive study of their thermal properties in aggressive environments is required. This work studied the influence of the characteristics of the habit of nickel crystals on their reactivity with increasing temperature (thermoreactivity). The authors studied nickel coatings produced by electrodeposition with the addition of inhibitory additives, in the form of alkali metal chlorides to the electrolyte. Differential thermal analysis was used to study the reactivity of coatings in temperature fields. Oxygen was used as an aggressive medium. The phase composition of the samples after heating was determined, using a powder X-ray diffractometer. The introduced additives in the form of alkali metal chlorides allowed forming coatings consisting of crystals of a cone-shaped habit. It was found that the introduction of additives, in the form of alkali metal salts into the electrolyte, makes it possible to change the habit of nickel crystals, and increase the surface area of the coating by approximately 10–15 %. The study showed that electrodeposited nickel coatings, consisting of crystals in the form of micro- and nanocones, have (compared to the control coating) a reduced thermoreactivity. Experimental data allowed concluding that a decrease in the intensity of oxidation on the coatings under study, may be associated with the presence of a preferential development of certain crystallographic faces of the crystals, which causes a change in the nature of the nickel-oxygen interaction, and as a consequence, a change in the oxidation intensity.

Exploring the potential of nickel-chloride bath for electroforming of pure nickel and nickel composites

Electroforming is becoming increasingly important as a reliable method for the production and replication of independent parts. Researchers are continually striving to reduce production costs for the fabrication of complex tools with the highest precision and lowest cost, and electroforming is a key technique for achieving this goal. The present research aimed to produce pure nickel foils via electroforming using a simple and inexpensive nickel-chloride bath, which has not been previously utilized for electroforming. The effects of saccharin concentration, nickel-chloride concentration, direct current density, and the use of graphite as an insoluble anode were investigated. The surface morphology of the electroformed products was characterized through scanning electron microscopy (SEM) and their chemical composition was analyzed using energy dispersive x-ray (EDX) and x-ray diffraction (XRD) pattern. The microhardness of the foils was determined using the Vickers hardness test. Results showed that specimens produced using the nickel-chloride bath had a good surface appearance with acceptable brightness and satisfactory microhardness. Ten electroforming tests were conducted to determine the optimal bath components, pH, and direct current density for the fabrication of pure nickel products. It was found that these parameters had a significant influence on the quality of the appearance and surface morphology of the foils. In addition, using a graphite anode was seen to reduce the cathode current efficiency as compared to a soluble nickel anode and was affected by the preferred orientation of nickel crystal plates. It can be concluded that the nickel-chloride bath has excellent potential for the production of pure nickel products using the electroforming method.

On the role of vacancy-hydrogen complexes on dislocation nucleation and propagation in metals

New insights are provided into the role of vacancy-hydrogen (VaH) complexes, compared to the hydrogen atoms alone, on hydrogen embrittlement of nickel. The effect of the concentration of hydrogen atoms and VaH complexes is investigated in different crystal orientations on dislocation emission and propagation in single crystal of nickel using atomistic simulations. At first, embrittlement is studied on the basis of unstable and stable stacking fault energies as well as fracture energy to quantify the embrittlement ratio (unstable stacking fault energy/fracture energy). It is found that VaH complexes lead to high embrittlement compared to H atoms alone. Next, dislocation emission and propagation at pre-cracked single crystal crack-tip are investigated under Mode-I loading. Depending upon the elastic interaction energy and misfit volume, high local concentrations at the crack front lead to the formation of nickel-hydride and nickel-hydride with vacancies phases. These phases are shown to cause softening due to earlier and increased dislocation emission from the interface region. On the other hand, dislocation propagation under the random distribution of hydrogen atoms and VaH complexes at the crack front or along the slip plane shows that VaH complexes lead to hardening that corroborates well with the increased shear stresses observed along the slip plane. Further, VaH complexes lead to the disintegration of partial dislocation and a decrease in dislocation travel distance with respect to time. The softening during emission and hardening during propagation and disintegration of partial dislocation loops due to VaH complexes fit the experimental observations of various dislocation structures on fractured surfaces in the presence of hydrogen, as reported in literature.

Multi-component delocalized nonlinear vibrational modes in nickel

Delocalized nonlinear vibrational modes (DNVMs) are relatively new dynamical objects that can be used for testing interatomic potentials and for classification and finding new types of discrete breathers. In this work, for the first time, multi-component DNVMs in a single crystal of fcc nickel are studied using molecular dynamics method. Previously discovered two one-component DNVMs are used to construct and investigate properties of all possible two- and three-component superpositions. A quasi-periodic energy exchange between components in multi-component DNVMs is described. If the amplitudes of the one-component DNVMs in a superposition differ by less than four times, then an equivalent energy exchange between them is observed. Otherwise, an unequal energy exchange takes place, i.e. when the high-amplitude component gives up only a part of its energy leading to a slight increase in the amplitude of another component. The DNVMs consisting of two- and three-components have a lifetime of more than 10 ps as long as the initial atomic amplitudes do not exceed 0.08 Å. An increase in the initial amplitude leads to a substantial decrease in the lifetime due to the rapidly developing modulational instability. Some superpositions of modes with the same initial amplitudes of the components can transform into a one-component DNVM, while others remain multi-component ones. The results obtained in this work demonstrate the existence of multi-component DNVMs, being a superposition of two or three components, which significantly expands our understanding of their dynamics in an fcc lattice.

Effect of Cu on Performance of Self-Dispersing Ni-Catalyst in Production of Carbon Nanofibers from Ethylene

The development of effective catalysts for the pyrolysis of light hydrocarbons with the production of carbon nanomaterials represents a relevant direction. In the present work, the influence of copper addition on performance of a self-dispersed Ni-catalyst and structural features of the obtained carbon nanofibers (CNFs) was studied. The precursors of Ni and Ni-Cu catalysts were prepared by activation of metal powders in a planetary mill. During contact with the C2H4/H2 reaction mixture, a rapid disintegration of the catalysts with the formation of active particles catalyzing the growth of CNFs has occurred. The kinetics of CNF accumulation during ethylene decomposition on Ni- and Ni-Cu catalysts was studied. The effect of temperature on catalytic performance was explored and it was shown that introduction of copper promotes 1.5–2-fold increase in CNFs yield in the range of 525–600 °C; the maximum CNFs yield (100 g/gcat and above, for 30-min reaction) is reached on Ni-Cu-catalyst at 575–600 °C. A comparative analysis of the morphology and structure of CNF was carried out using electron microscopy methods. The growth mechanism of carbon filaments in the shape of “railway crossties” on large nickel crystals (d > 250 nm) was proposed. It was found that the addition of copper leads to a decrease in the bulk density of the carbon product from 40–60 to 25–30 g/L (at T = 550–600 °C). According to the low-temperature nitrogen adsorption data, specific surface area (SSA) of CNF samples (at T < 600 °C) lies in the range of 110–140 m2/g, regardless of the catalyst composition; at T = 600 °C the introduction of copper contributed to an increase in the specific surface of CNF by 100 m2/g.

Fatigue Crack Growth in a Monocrystal and Its Similarity to Short-Crack Propagation in a Polycrystal of Nickel

Short fatigue cracks in polycrystalline materials are very important from both practical and basic aspects, yet they are very difficult to observe. Therefore, it is suggested to emulate some properties of short cracks with long fatigue cracks in monocrystals. Indeed, such experiments in pure nickel crystals prove that the three peculiar properties of short fatigue cracks in polycrystalline metals are observed in long cracks in monocrystals, i.e., a lower threshold of the stress intensity factor (ΔKI)th, a higher crack propagation rate at low ΔKI regimes, and the fact that different cracks exhibit different growth behaviors. The fatigue experiments in monocrystals reveal interesting details of the slip activity at the front of fatigue cracks, including a selection rule for the active slip systems above and below the crack, the slip behavior under conditions of steep strain gradients, and the activation of a new slip system.

ТЕХНОЛОГИЯ КРИСТАЛЛИЗАЦИОННОГО РАЗДЕЛЕНИЯ НИКЕЛЯ И КАДМИЯ ПРИ ПЕРЕРАБОТКЕ НИКЕЛЬ-КАДМИЕВОЙ ЭЛЕКТРОДНОЙ МАССЫ ЩЕЛОЧНЫХ АККУМУЛЯТОРОВ

The main stages of processing nickel-cadmium electrode mass of alkaline batteries, including: sulfuric acid leaching and subsequent crystallization of the main components of the system - cadmium and nickel in the form of double sulfates MSO4·(NH4)2SO4·6H2O (Tutton's salts), where M = Ni, Cd. As a result of the research, regularities in the behavior of nickel and cadmium at the stage of leaching with a solution of sulfuric acid and crystallization of double sulfates were revealed. It is shown that the separation of cadmium and nickel in the sulfuric acid solution of leaching of nickel-cadmium battery mass by crystallization of nickel and cadmium-ammonium double sulfates is achieved in three stages with the formation of crystals of the composition NiSO4·(NH4)2SO4·6H2O, in two stages of crystallization and the degree of extraction of nickel 99 %, as well as CdSO4·(NH4)2SO4·6H2O and CdSO4·(NH4)2SO4 at the third stage of crystallization. Iron remains in solution after all valuable components have been isolated.

Fabrication and performance of nickel-based composite mold inserts for micro-injection molding

During the demolding stage of micro-injection molding (μIM), reducing the interfacial interactions (mainly adhesion and friction forces) between the contact interfaces is the key to achieve non-destructive molding of polymer micro/nano structures. In this study, Ni-based composite mold inserts using polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS2) and tungsten disulfide (WS2) with low surface energy and low friction coefficients were fabricated by electroforming. Different nanoparticles could be uniformly distributed in the composite mold inserts without agglomeration at low concentrations, and the orientation of nickel crystal was found to be unchanged by phase composition analysis. The surface energy and adhesion of the inserts could be effectively reduced after the addition of nanoparticles. The molecular dynamics simulation results showed that the value of water contact angle could be closer to the experimental value by adding a surface roughness factor. Due to the self-lubricating property of nanoparticles, the friction coefficient was reduced from 0.75 for pure Ni to 0.25 for WS2 with a concentration of 0.2 g/L. The use of the composite mold inserts with low surface energy and low friction coefficient would solve the problem of microstructure deformation in the demolding stage of injection molded polymer microfluidic chips.

Study on interfacial thermal resistance between single wall carbon nanotubes and nickel by molecular dynamics

The interfacial thermal resistance of the nanocontact system of carbon nanotubes and nickel crystals was investigated using molecular dynamics. It was found that with the increase in temperature, the interface thermal resistance gradually increased. In addition, the interfacial thermal resistance also increases gradually with the increase of the contact distance. The ballistic transport of phonons is proposed to be the main reason for the interfacial thermal resistance in this case.

Manufacturing single crystals of pure nickel via selective laser melting with a flat-top laser beam

• Fabrication of single-crystal structure using selective laser melting was studied. • A flat-top profile was utilized without the implementation of single-crystal seeds. • Parametric optimization resulted in planar melt pool formation. • A homogeneous near-{001}<100> texture was achieved in high building heights. • Suppressing strain accumulation was necessary to avoid high-angle grain boundary. The exploration of flat-top laser profile in fabricating a single crystal (SX) structure using selective laser melting (SLM) in pure Ni was investigated. Optimization of the parameters led to the formation of a planar melt pool. A homogeneous near-{001}<100> texture with suppressed high-angle grain boundary (HAGB) in high building heights of >20 mm was achieved without an SX seed. In addition, the planar melt pool suppressed the geometrically necessary dislocation accumulation and prevented strain-induced continuous dynamic recrystallization that could cause HAGB formation. Thus, an SX structure with homogeneous near-{001}<100> texture and suppressed HAGB was successfully achieved without an SX seed.

Double-slit interference and single-slit diffraction experiments on electrons

De Broglie proposed the matter wave in 1924. The de Broglie wave is neither a mechanical wave nor an electromagnetic wave and has a very short wavelength. The Davisson-Germer electron diffraction experiment performed in 1925 involved bombarding the surface of a nickel crystal with a narrow beam of electrons. When the accelerating voltage V was maintained at 54 V, the wavelength of the incident electron was λ=h/ &lt;mml:math display="inline"&gt; &lt;mml:msqrt&gt; &lt;mml:mn&gt;2&lt;/mml:mn&gt; &lt;mml:mi mathvariant="normal"&gt;m&lt;/mml:mi&gt; &lt;mml:mi mathvariant="normal"&gt;e&lt;/mml:mi&gt; &lt;mml:mi mathvariant="normal"&gt;V&lt;/mml:mi&gt; &lt;/mml:msqrt&gt; &lt;/mml:math&gt; = 0.167 nm [Y. S. Chen and Z. Z. Li, College Physics (Tianjin University, Tianjin, 1999)] demonstrating the existence of the matter wave. We introduce a type of electron wave with a very long wavelength in this study that is different from the matter wave. For example, the wavelength of the electron wave can reach 0.43 mm in the double-slit interference of electrons. Experiments demonstrate that this long-wavelength electron wave can produce both double-slit interference and electron diffraction. A comparative analysis of matter and electron waves reveals the physical natures of these waves and wave‐particle duality.

Shock resistance capabilities of nickel crystal containing helium nanobubbles

It has been revealed in previous studies that helium bubbles have a damaging consequence on the load bearing capabilities of nickel. Shock resistance is the key characteristic of structural materials used in the construction of a nuclear reactor. Herein, atomistic simulations were performed to study the dynamic shock resistance capabilities of single crystal Ni impregnated with helium bubble. The effect of the geometrical configuration of helium bubble on a nickel crystal, which acts as a substrate in which the bubble is lodged, when subjected to shock loading, was studied. It was concluded from the atomistic simulations that the presence of helium bubble with a higher concentration of helium atom leads to a reflection of shock front energy from the shock path. The diameter of the helium bubble at the same concentration of He (the ratio of He atoms to the vacancy created by deleting Ni atoms) is less critical for the shock resistance capabilities of Ni crystal. At lower values of shock impact, the deformation is mainly controlled by dislocation emission, whereas at higher impact velocities, the phase transformation from FCC to BCC is the primary mode of deformation. The analysis presented in this article will help in elucidating the shock resistant capabilities of Ni facing challenges of transmutation.

Microstructures and properties of nickel-titanium carbide composites fabricated by laser cladding

In this work, Ni/TiC composites were synthesized by the laser cladding technique (LCT). A scanning electron microscope (SEM), X-ray diffractometer (XRD), microhardness meter, electrochemical workstation, and friction and wear tester examined the microstructure, surface morphology, phase structure, microhardness, wear, and corrosion resistances of the Ni/TiC composites. These results indicated the Ni/40TiC composite contained finer equiaxed crystals than the Ni and Ni/20TiC composites. In addition, numerous TiC particles in the Ni/40TiC composite impeded growth of the nickel crystals, which resulted in the fine microstructure of the Ni/40TiC composite. The Ni, Ni/20TiC, and Ni/40TiC composites exhibited face-centered cubic (f c c) lattices. The average microhardness values of the Ni/20TiC and Ni/40TiC composites were approximately 748 HV and 851 HV, respectively. The Ni/40TiC composite had the lowest friction coefficient (0.43) among all three coatings, and only some shallow scratches appeared on the surface of the Ni/40TiC composite. The corrosion potential (E) of Ni/40TiC exceeded the Ni/20TiC composite, and both were larger than the Ni composite, which indicated the Ni/40TiC composite had outstanding corrosion resistance and the Ni composite had poor corrosion resistance. The corrosion current densities (i) of Ni, Ni/20TiC, and Ni/40TiC composites were 5.912, 4.405, and 3.248 μA/cm2, respectively.

Hydromechanics for crystal growth from water-salt solutions

This paper presents an overview of the current state of technological problem solving related to controlling of hydrodynamics and mass transfer in crystallizers of complex design (continuous-flowing and non-flowing) during the growth of crystals with technologically important properties (potassium dihydrogen phosphate - KDP and a mixed crystal of nickel and cobalt - KCNSH) from special water-salt solutions. Unlike crystallizers of standard designs for crystal growth from a melt (by Czochralski, Bridgman, etc.), there are also crystallizers of different design for crystal growth from water-salt solutions. According to the designers, the necessary crystal growth conditions are maintained in these crystallizers by creating the best characteristics of the flow, i.e., by controlling its velocity and direction, as well saline saturation solution and temperature. In this work, hydromechanical problems are solved for continuous-flowing and non-flowing crystallizers. The flow visualization through its physical model reveals a multi-vortex and unsteady flow structure due to mixer action, three-dimensional solution inflow and outflow and spatial crystal placement. For this reason, primary attention is given to the studies devoted to the development and application of the mathematical models for hydromechanics and heat and mass transfer based on the complete Navier-Stokes equations in the Boussinesq’s approximation for laminar regimes, as well as to the standard (k-ε)-turbulence model for turbulent regimes. The hydromechanical features associated with the three-dimensional flow complexity are discussed for continuous-flow crystallizers. The possibilities of maintaining the required saline saturation near the growing crystal over a long period of time are analyzed for non-flowing crystallizers. Mathematical models of convective mass transfer are considered in a "solution-crystal" conjugate formulation. The local features of hydrodynamics and mass transfer conditions in solution (saline solution saturation near growing crystal) are analyzed.