Codeposition Behavior Research Articles

Codeposition Behavior of the Particles and their Surface Treatments in Composite Plating

Codeposition Behavior of the Particles and their Surface Treatments in Composite Plating

Electrodeposition of equiatomic FeNi and FeCo nanowires: Structural and magnetic properties

In the present work, equiatomic FeNi and FeCo magnetic nanowires (NWs) have been electrodeposited in Anodic Aluminum Oxide (AAO) membranes with 70 nm pore size. The role of the electroactive species Ni2+ and Co2+ on the anomalous codeposition behavior in thin films and nanowires has been discussed and compared. Field Emission Gun-Scanning Electron Microscope (FEG-SEM), X-ray diffraction (XRD) and Vibrating Sample Magnetometer (VSM) were used to evaluate the morphology, composition, crystalline structure and magnetic properties of the materials. SEM-FEG analysis showed very homogeneous NWs lengths for both FeNi and FeCo NWs, Energy dispersive X-ray spectroscopy (EDS) analysis revealed a stable composition along the FeCo NWs and a change in composition along the FeNi NWs. The XRD patterns indicate the predominance of the bcc structure for both alloys. Except for additional peaks of fcc phase found on FeNi alloy, the same crystalline bcc structure is observed after annealing treatment of 300 °C during 20 h. TEM analysis confirmed the ordered character of the bcc FeCo alloy. The hysteresis loops show an easy magnetization direction parallel to the wires due to the predominance of the shape anisotropy. The coercive field (Hc) of FeNi NWs increases with the length of the wires while that of FeCo NWs decreases. The annealing treatment doesn’t affect the magnetic properties of FeNi NWs, whereas a remarkable increase in the coercivity of the FeCo NWs is observed.

Co-deposition and electrokinetic behavior of TiO2–WO3 nanoparticles under non-uniform AC field

AbstractThe electrokinetic behavior of TiO2–WO3 nanoparticles while applying non-uniform AC electric fields at a frequency of 10 kHz was investigated using planar parallel electrodes. For this purpose, WO3 and TiO2 nanoparticles, which exhibited a different response to the applied electric field, were deposited simultaneously at 10 kHz. Characterization of the obtained patterns by optical and scanning electron microscopy revealed that the TiO2 nanoparticles, which were unable to enter the gap, moved toward it and got deposited there in the presence of WO3 nanoparticles. Hence, a composite layer consisting of TiO2 and WO3 nanoparticles was formed in the gap. A hypothesis for the change in the deposition and electric behavior of TiO2 nanoparticles is presented in this paper using the multi-shell model. Furthermore, a possible method for the fabrication of a TiO2–WO3based gas sensor has been provided.

Coupled Electrodeposition of Fe-Co-W Alloys: Thin Films and Nanowires.

The electrodeposition of Fe–Co–W alloys was examined using a rotating cylinder Hull (RCH) cell and conditions were determined to create nanowires. The metal ion reduction mechanism was a combination of induced and anomalous codeposition, with water reduction as a gas evolving side reaction, rending deposition into recesses a challenge. In thin film deposition, under kinetic control, the addition of Fe ions into the electrolyte, greatly reduced the Co partial current density, and thus it's content in the deposit. The change of Co partial current density was attributed to an anomalous codeposition behavior, but it had a minimal effect in changing the W wt% in the deposit, despite the expected inducing characteristic of Fe when codeposited with tungsten. Deposition conditions were determined to electrodeposit Fe–Co–W nanowires having similar concentration as the thin films. Nanowires were electrodeposited into polycarbonate membranes under pulsed current at room temperature.

Corrosion behavior of Ni–P–Ag and Ni–P–Al2O3 composite coatings

The aim of this research is to study the co-deposition behavior of Ag and Al2O3 particles within Ni–P coating and the corrosion resistance of Ni–P–Ag and Ni–P–Al2O3 composite coatings. The structure of the composite deposits was evaluated by XRD and the morphology and cross-section of the coatings were analyzed by SEM and TEM. 3D optical profilometer was also used to determine the surface roughness of the coatings and the co-deposition percentage was calculated by the image analysis of micrographs. The electrochemical behavior of the coatings were evaluated by open circuit potential (OCP) measurements, potentiodynamic polarization and also electrochemical impedance spectroscopy (EIS) techniques. The results showed that the Al2O3 particles were co-deposited more than that of Ag particles in the existence of CTAB cationic surfactant whereas maximum co-deposition were achieved about 20 and 34 vol% in Ni–P–Ag and Ni–P–Al2O3 composite deposits. Moreover, the phosphorus content and especially the deposition rate of Ni–P matrix coating were strongly influenced by the concentration of the particles in plating solution. The different co-deposition behavior of these two types of reinforcements have been directly correlated to the density, particle size and zeta potential of the particles. The EIS results revealed that the incorporation of Ag and alumina powder in Ni–P matrix cause the lower corrosion resistance rather than that of conventional Ni–P coating. This behavior has been attributed to the pore formation in the composite deposits as well as the galvanic corrosion especially in Ni–P–Ag composite coating.

An investigation of structural properties and surface morphologies ofelectrochemically fabricated nanocrystalline Ni-Co-Cu/ITO deposits withdifferent compositions

In this study, nanocrystalline ternary Ni-Co-Cu/ITO deposits with different compositions were produced by using the electrochemical deposition technique from a sulfate-based bath solution with different Co ion concentrations. It was revealed that an increment in the Co ion concentration gives rise to an enhancement in the Co content but leads to a decrement in the Ni and Cu contents of the deposit structure. The Co-Cu and Ni-Cu exhibited normal codeposition behavior, while the Co-Ni showed anomalous codeposition behavior irrespective of the bath concentration. The change in the degree of the anomalous codeposition was also investigated according to the Co ion concentration. The deposits exhibited a dual face-centered cubic (fcc) phase structure comprising Cu and Ni-Co phases. The strength of the Ni-Co (111) (Cu (111)) phase increased with respect to the Cu (111) (Ni-Co (111)) phase when the Co (Cu) content in the ternary Ni-Co-Cu deposit increased. The size of the crystallites, the value of the interplanar spacing, and the crystallinity of the deposits changed depending on the deposit composition. It was also revealed that the differences in the deposit composition highly affect the average diameter and the density of the agglomerated clusters formed on the deposit surfaces.

Codeposition of Nanocrystalline Co-Ni Catalyst Based on 1-ethyl-3-methylimidazolium Bisulfate and Ethylene Glycol System for Hydrogen Evolution Reaction

The codeposition behavior of Co(II) and Ni(II) in 1-ethyl-3-methylimidazolium bisulfate ([EMIM]HSO4) ionic liquid (IL) and ethylene glycol (EG) system is recorded using cyclic voltammetry (CV). The result indicates that the mechanism of Co-Ni codeposition is an anomalous codeposition, and both the inhibition for Ni(II) reduction and the anomalous codeposition phenomena can be improved by the increase of Co(II) concentration in the system. These Co-Ni deposits are characterized using EDS, XRD and SEM. SEM micrographs indicate that the surface morphology of Co-Ni deposits can be changed by the increase of Co content, and these deposits with many additional elongated acerose crystals, which are germinated on the spherical “nodules” surface, can be prepared. XRD pattern reveals the feature peak of crystalline Co1.2Ni2.8 with a preferred orientation direction and the average size of grains is calculated to be about 14.6 nm. Moreover, the electrocatalytic activity for hydrogen evolution reaction (HER) on the prepared Co-Ni catalyst surface is investigated using linear sweep voltammetry (LSV) and electrochemical impedance spectra (EIS). These results indicate that the obtained catalyst presents an excellent electrocatalytic activity and durability for HER with an overpotential of 139 mV at 10 mA cm−2 in 1 M KOH solution.

Pulse and Pulse Reverse Electrodeposition of Cubic, Tetragonal and Its Mixed Phase of Ni-W Alloys for Corrosion Applications

Ni-W alloy coatings on mild steel substrate with various crystalline structures were prepared using pulse and pulse reverse electrodeposition method for corrosion protection application. The co-deposition behavior of tungsten and basic electrochemical information of electrolytes were confirmed through cyclic voltammetry studies. The crystalline nature, alloy phase and it is crystal (cubic and tetragonal) phase transformations were confirmed using X-ray diffractions. The corrosion resistance performances of the deposits were studied using Tafel polarization and electrochemical impedance studies. Correlation between the crystal structures and its corrosion resistance performance were explored and tetragonal Ni-W alloy film having better corrosion resistance than cubic Ni-W alloy film. The mixed phase of tetragonal dominated cubic structures in the alloy matrix has the superior corrosion resistance performance. This study confirms the Ni-W alloy films have good corrosion protection and this can be tuned with the modification of crystal structure using various deposition conditions.

Low-pressure electroneutral loose nanofiltration membranes with polyphenol-inspired coatings for effective dye/divalent salt separation

Low-pressure electroneutral loose nanofiltration (NF) membranes were facilely fabricated by co-deposition of polyphenol-inspired epigallocatechin gallate (EGCg) and polyethyleneimine (PEI) on polyethersulfone (PES) ultrafiltration substrates. The effects of PEI with different molecular weights on co-deposition behavior, morphologies, surface properties, as well as separation performance of the resultant membranes were investigated in detail. The results showed that with the increase of PEI molecular weight from 600 to 10,000, the co-deposition amount of EGCg/PEI on membrane surface decreased, while the EGCg/PEI selective layer became denser. As a result, the EGCg/PEI 600 co-deposited membrane, which possessed an electroneutral surface with the best hydrophilicity, exhibited the optimal separation performance among the co-deposited membranes in the context of textile wastewater treatment. It had the highest pure water permeability (19.0 L/(m2·h·bar)) and excellent rejections towards dyes with different charges (e.g. 99.0% for Congo Red) as well as the lowest rejections towards divalent salts (e.g. 4.1% for Na2SO4) at an operating pressure of 2 bar. Moreover, the membranes exhibited good organic solvent resistance, structural stability together with favorable performance in dealing with textile effluent, demonstrating their great potential in practical applications.

A Comparative Study on Microstructures, Magnetic Features and Morphologies of Ternary Fe–Co–Ni Alloy Thin Films Electrochemically Fabricated at Different Deposition Potentials

Electrochemically fabricated ternary Fe–Co–Ni alloy thin films with different chemical compositions were obtained at different deposition potentials. An increase in the deposition potential increased the Ni content while it decreased the Co and Fe contents in the film structure. An anomalous co-deposition behaviour was also studied and the anomalous order of co-deposition was found to be Fe–Ni > Co–Ni > Fe–Co irrespective of deposition potential. Structural characterizations confirmed the presence of single face-centred cubic (fcc) phase structure with [111] preferred crystallographic orientation for all films. The size of the crystallites and the texture degree increased with increasing applied deposition potential. Smaller globular particles occurred on the surface structure of the film fabricated at higher deposition potentials compared to those grown at lower deposition potentials. A decrement detected in the coercive field with increasing applied deposition potential was related to the variations occurred in the chemical composition and the particle size.

Electrowinning of U-Pu onto inert solid cathode in LiCl-KCl eutectic melts containing UCl3 and PuCl3

Electrowinning process was investigated for extracting actinides from molten salts used for the pyrochemical reprocessing of spent nuclear fuels. The separation of actinides from lanthanides is expected to be enhanced by employing inert solid cathodes due to larger potential differences on these cathodes. In this study, the co-deposition behavior of Pu and U metals onto an inert solid cathode made of tungsten was examined in LiCl-KCl eutectic melts containing UCl3 and PuCl3 at 773 K. The standard potential of U3+/U is 0.31 V more positive than that of Pu3+/Pu. The U3+ concentration was varied in the range of 0.11–0.66 wt%, while the Pu3+ concentration was maintained at approximately 2.9 wt%. When the U3+ concentration was not sufficiently low, the deposited U metal readily grew outward from the electrode surface and the electrode surface area rapidly increased, which facilitated only the deposition of U metal. It was estimated that metallic Pu can be efficiently collected along with U at U3+ concentrations lower than ∼0.2 wt%.

Insight into the Mechanism of the Fe-Ni Alloys Co-Deposition from Poly-Nuclear Complexes

Electrodeposition of the Fe-Ni alloys in the citrate bath was anomalous co-deposition, but normal co-deposition in the citrate-ammonia bath. The Fe and Ni elements were uniformly distributed in the Fe-Ni deposit, which were highly alloyed. These results cannot be simply explained by the hydroxide deposition model or the competitive adsorption of intermediate model, which proposed in literature. A poly-nuclear complex co-deposition mechanism of Fe-Ni alloy was proposed in the above two baths, which can explain better electro-deposition behavior of the Fe-Ni co-deposition and the experimental phenomena we observed.

The Effect of SiC Nanoparticle Size on the Electrodeposition of Zn–SiC Nanocomposite Coatings from Citrate Bath

A comparison is made between the codeposition behavior of Zn with SiC nanoparticles (NPs) of two average sizes: 56 nm and 90 nm. The SiC NPs are first characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD). Dynamic light scattering (DLS) is used to compare the surface charge of both kinds of SiC NPs suspended in aqueous citrate electrolytes. The effect of applied current density, hydrodynamic conditions, and total charge passed on the SiC content in the coating and electrodeposition rate is studied. The electrodeposited Zn-SiC coatings are characterized by wavelength dispersive X-ray fluorescence (WDXRF), scanning electron microscopy (SEM), and XRD. The results obtained confirm that Cit-Zn complexes are adsorbed on the surface of the SiC NPs, which are transported to the cathode and are codeposited with Zn during reduction. Zn-SiC incorporation may proceed also by mechanical entrapment of SiC agglomerates in the cavities and pores that are formed in the deposit under condition of relatively fast Zn deposition, which is accompanied by fast hydrogen evolution.

A comparative study on the electrocatalytic activity of electrodeposited Ni-W and Ni-P alloy coatings

Bright Ni-W and Ni-P alloy coatings were synthesized through direct electrolysis from an aqueous alkaline citrate bath. The effect of alloying elements, W and P, on the electrocatalytic activity of Ni was studied, based on their induced codeposition behavior and related to the composition, structure and surface morphology of the developed coatings. The electrocatalytic activity of the alloy coatings towards hydrogen evolution reaction (HER) was studied using electrochemical techniques such as cyclic voltammetry (CV) and chronopotentiometry (CP), in 1.0 M KOH medium. A comparison of the electrocatalytic efficiencies of these Ni-based alloys was made in consideration with its physical and electrochemical characteristics. The obtained results showed that the alloying of Ni with W gives superior properties towards HER, attributed by its better hydrogen adsorption energy than in Ni-P alloy. The surface appearance, chemical composition and phase structure of the coatings were studied using SEM, EDS and XRD analyses, respectively.

Synthesis of Ni-Fe thin films by electrochemical deposition technique and characterization of their microstructures and surface morphologies

Microstructural features and surface morphologies of Ni-Fe thin films fabricated by the electrochemical deposition technique have been experimentally studied. Ni-Fe thin films have been deposited under different deposition potentials and FeSO$_{4}$ concentrations. Energy dispersive X-ray measurements demonstrate that the Fe content decreases (increases) as the deposition potential (FeSO$_{4}$ concentration) is enhanced. All of the produced films exhibit an anomalous codeposition behavior. The effects of deposition potential and FeSO$_{4}$ concentrations on the degree of anomalous codeposition have been also characterized. X-ray diffraction studies reveal that the films have face-centered cubic crystallographic structures with [111] preferred crystallographic orientation regardless of the applied deposition conditions. However, the crystallization and the crystallite size of the films are affected by changing of the FeSO$_{4}$ concentration and the deposition potential. The results of scanning electron microscopy analyses verify that the surface structure of the film electroplated from the electrolyte with higher FeSO$_{4}$ concentration under higher deposition potential exhibits a more homogeneous and dense structure with smaller grain sizes.

Microstructural characterization and corrosion behaviors of Ni-Cu-Co coatings electrodeposited in sulphate-citrate bath with additives

Abstract Nanocrystalline Ni-Cu-Co coatings with face centered cubic (F.C.C.) structure were electrodeposited in sulphate-citrate bath with additives. Composition analysis showed that an anomalous co-deposition behavior of nickel-cobalt was maintained and hardly affected by copper (II) concentration in the copper- and additives-contained bath. Use extrapolation method according to the Nelson-Riley function and X-ray diffraction (XRD) profile analysis to estimate microstructure of the coatings. The results showed that the lattice parameter, microstrain and dislocation density increased and the grain size decreased with the increments of copper and cobalt incorporated into nickel. The coatings displayed a sliver-mirror-like appearance and lots of pores formed on surface. Especially, more large pores appeared on the copper-rich (44–49 wt.%) coatings. The coating comprised of 49 wt.% nickel, 13.5 wt.% copper and 37.5 wt.% cobalt attained a maximum microhardness. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were employed to investigate the corrosion behaviors of the coatings. The coating comprised of 50.3 wt.% nickel, 34.7 wt.% copper and 15 wt.% cobalt possessed higher electrochemical impedance than the copper-rich coatings, exhibiting a better corrosion resistance in 3.5 wt.% NaCl solution.

Differences observed in the surface morphology and microstructure of Ni-Fe-Cu ternary thin films electrochemically deposited at low and high applied current densities

In this research, nanocrystalline Ni-Fe-Cu ternary thin films using electrochemical deposition technique were produced at low and high applied current densities onto Indium Tin Oxide (ITO) coated conducting glass substrates. Change of surface morphology and microstructural properties of the films were investigated. Energy dispersive X-ray spectroscopy (EDX) measurements showed that the Ni-Fe-Cu ternary thin films exhibit anomalous codeposition behaviour during the electrochemical deposition process. From the X-ray diffraction (XRD) analyses, it was revealed that there are two segregated phases such as Cu- rich and Ni-rich within the films. The crystallographic structure of the films was face-centered cubic (FCC). It was also observed that the film has lower lattice micro-strain and higher texture degree at high applied current density. Scanning electron microscopy (SEM) studies revealed that the films have rounded shape particles on the base part and cauliflower-like structures on the upper part. The film electrodeposited at high current density had considerably smaller rounded shape particles and cauliflower-like structures. From the atomic force microscopy (AFM) analyses, it was shown that the film deposited at high current density has smaller particle size and surface roughness than the film grown at low current density.

Positively charged nanofiltration membranes via economically mussel-substance-simulated co-deposition for textile wastewater treatment

Herein, a novel positively charged nanofiltration (NF) membrane has been facilely fabricated via a highly efficient one-step mussel-substance-simulated co-deposition of low-cost catechol and branched polyetheylenimine (PEI) onto substrates. The co-deposition behaviour, physicochemical properties and separation performances of resultant membranes can be readily tailored by varying PEI molecular weight. In particular, the catechol/PEI600 co-deposited NF membrane shows good removals toward dyes, common salts and heavy metal ions for textile wastewater treatment. Our membranes exhibit high removal efficiency toward cationic dye and metal ions due to the Donnon effect. In addition, EtOH activation process can greatly enhance the membrane permeance with a factor of 1.8–2.4 without compromising rejection. Especially, the novel membranes show stable long-term separation performance toward MgCl2 removal, and the dye-fouled co-deposited membranes can be facilely regenerated and reused with a simple static immersion operation. The co-deposited membrane can perform well in alcohols solvents, indicating its excellent performance for practically environmentally-friendly usages. The facile strategy disclosed in our study can provide new opportunities to not only nanofiltration membrane modification but also the surface engineering of vast kinds of materials towards energy and environmental applications.

Effects of current density and agitation on co-deposition behaviour of electrodeposited Ni–TiO2 composite coating

In the present study, the effects of current density and agitation on the behaviour of co-deposition of TiO2 particles in an electrodeposited nickel were investigated. The electrodeposited Ni–TiO2 composite was manufactured from a nickel sulfamate bath containing TiO2 particles. The volume fraction of the incorporated TiO2 particles, the current efficiency (C.E.) and the hardness were measured in different current densities, magnetic bar speed and flow rate of the air bubble. The results indicate that the volume fraction of TiO2 particles in the nickel matrix increased with a decrease of the C.E. at the mass transfer region, but the opposite tendency was observed under the charge transfer region. The hardness of the Ni–TiO2 composite increased normally with an increase in the volume fraction of the TiO2 particles. However, the hardness increased with a decrease in the volume fraction at a lower current density region owing to the hardening of the nickel matrix.

Electrochemical Co-Deposition of Iron and Nickel from a Hydrophobic Ionic Liquid

Electrochemical reactions of Ni(II)/Ni and Fe(II)/Fe were investigated in a hydrophobic room-temperature ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing Ni(TFSA)2 and Fe(TFSA)2. The optimal conformation of high-spin metal ion (M(II) = Fe(II) and Ni(II)) with three trans-TFSA− were obtained using the theoretical calculations. The bigger molecular volume of Fe(II) species in BMPTFSA may lead to a smaller reduction peak current. The cyclic voltammetric results showed that the cathodic peaks of Ni(II) and Fe(II) emerged into one wave, which is close to the cathodic waves of individual metals and favorable for the co-electrodeposition of Ni-Fe. A non-anomalous codeposition behavior was found from BMPTFSA with Ni(TFSA)2 and Fe(TFSA)2. Ni-Fe deposits with different morphology and composition were obtained at various applied potentials and metal ion concentrations.