Magnetoelectrodeposition Research Articles

Comparison Study the Modeling of Limiting Current in the Magneto Electrodeposition of Vanadium using Neural-Wiener Model and Feed Forward Neural Network

Vanadium has long been used as a corrosion-resistant coating, including as a metal alloy for battery cathodes. However, batteries discovered with non-smooth cathode surfaces due to the fabrication process have a short battery life. So, a cathode coating stage is required via the electroplating method under the influence of a magnetic field or Magneto Electro Deposition (MED). Knowing the limiting current in MED is very important because the optimum mass transport achieves at the limiting current (iB). The smoothest and most compact electrodeposit surface will occur at this limiting current. In this study, Feed Forward Neural Network and Neural-Wiener are suggested and compared as a nonlinear modeling approach to determine the ideal limiting current because of their strong capacity to anticipate the link between input and output from experiment data. The Levenberg-Marquadt optimization technique with hidden neurons was used to evaluate and compare the modeling capabilities of two neural networks, the Feed Forward Neural Network, and the Neural Wiener. The results of this study are presented as a comparison of the Mean Square Error (MSE) values obtained from the nonlinear modeling of two artificial neural network algorithms. The algorithm that models the ideal current limiting has the lowest MSE value (iB).

Effect of Magnetic Field on Corrosion Performance of Ni–Co Alloy Coatings

The corrosion protection efficacy of Ni–Co alloy coatings was tried to improve by magnetoelectrodeposition (MED) approach. The magnetic field of varying strength (B) was applied in perpendicular and parallel to the direction of diffusion of metal ions, simultaneously to the process of deposition. The corrosion behaviour of the deposited coatings was studied through electrochemical DC method and results revealed that Magneto-electrodeposited (MED) Ni–Co alloys coatings were found to be more corrosion resistant than their conventionally electrodeposited (ED) counterparts. Moreover, the effect of magnetic field is more pronounced in perpendicular field direction and was explained by Lorentz force. Under optimal condition, MED Ni–Co alloy coating obtained at a magnetic field intensity of B = 0.3 T (Perpendicular) was found to be less prone to corrosion than its ED alloy (B = 0 T) counterpart. The increased limiting current density (iL) of Co2+ ions in turn increases the corrosion resistant properties of MED Ni–Co alloy coatings. The effect of magnetic field on improved corrosion resistance of the deposited coatings have been investigated in terms of their changed surface morphology, composition, phase structure and surface roughness using Scanning electron microscopy (SEM), Energy dispersion spectroscopy (EDS), X-Ray diffraction (XRD) technique and Atomic Force Microscopy (AFM) respectively.

Electrochemical analysis study of rare earth element: Lanthanum under the effect of magnetic field and its application as an additive for chrome magneto electrodeposition

Lanthanum is a rare earth group that is increasingly needed for a variety of applications. In this study, we analyze the effect of magnetic fields on lanthanum electrodeposition. Electrochemical analysis techniques used are linear sweep voltammetry (LSV) and Chronoamperometry (CA). LSV is used to measure the maximum current (limiting current). To determine the maximum current, the result of the LSV must be plotted in a Tafel plot. Tafel generated from LSV is the electrode potential (mV) with the logarithm of the current density (Log iL (A·cm–2)). The diffusion coefficient of the electroactive species was determined using chronoamperometry (CA). The results showed that the effect of increasing the working electrode area (A), magnetic field strength (B), and electroactive concentration (C) gave a certain increase in limiting current. Meanwhile, the addition of solution viscosity (v) and diffusion coefficient (D) will reduce the limiting current value for lanthanum electrodeposition. This study also carried out a chrome-plating process with the addition of lanthanum which was studied previously, it was found that the plating process using magnetic field produced a more uniform; thicker; more compact, and more mass deposit.

Study of magnetoelectrodeposition of lanthanum (III) chloride heptahydrate leached with sulfuric acid

Abstract A rare-earth element (REE) is one of the minerals with many resources in Indonesia and lanthanum is one of REE. Lanthanum is widely used as a material for x-ray screens, glass lenses, optical fiber, capacitor batteries, and ceramics. Electrodeposition is a metal deposition process. The advantages of electrodeposition are easy and inexpensive. The method is simple since it can be done at room temperature, and it is inexpensive because it only requires basic equipment. However, there is a drawback to conventional electrodeposition: the roughness of the resultant layer (non-uniform crystal growth). Magnetoelectrodeposition (MED) is a solution for solving this problem. We employed the MED method in this study, which is the electrodeposition procedure under the influence of a magnetic field, and there has been no previous research on lanthanum MED. The electrode area, magnetic field strength, electroactive concentration, diffusion coefficient, and kinematic electrolyte viscosity were variables used in this study. The lanthanum MED in this study used 98% lanthanum (III) chloride heptahydrate (LaCl3.7H2O) for analysis from Merck, which was leached at a particular concentration of sulfuric acid (H2SO4), using platinum electrodes in three electrochemical cells, and varying the magnetic field strength from 0 to 0.08 Tesla. The results showed that the stronger the magnetic field, the greater the limiting current for lanthanum electrodeposition. The effect of electrode area and electroactive concentration also gives rise to the limiting current. Meanwhile, the viscosity of the solution and the diffusion coefficient will cause a reduction in limiting the current value.

Magneto-Electrodeposition of 3D Cross-Linked NiCo-LDH for Flexible High-Performance Supercapacitors.

Layered double hydroxides (LDHs) with outstanding redox activity on flexible current collectors can serve as ideal cathode materials for flexible hybrid supercapacitors in wearable energy storage devices. Electrodeposition is a facile, time-saving, and economical technique to fabricate LDHs. The limited loading mass induced by insufficient mass transport and finite exposure of active sites, however, greatly hinders the improvement of areal capacity. Herein, magneto-electrodeposition (MED) under high magnetic fields up to 9 T is developed to fabricate NiCo-LDH on flexible carbon cloth (CC) as well as Ti3 C2 Tx functionalized CC. Owing to the magneto-hydrodynamic effect induced by magnetic-electric field coupling, the loading mass and exposure of active sites are significantly increased. Moreover, a 3D cross-linked nest-like microstructure is constructed. The MED-derived NiCo-LDH delivers an ultrahigh areal capacity of 3.12 C cm-2 at 1mA cm-2 and as-fabricated flexible hybrid supercapacitors show an excellent energy density with an outstanding cycling stability. This work provides a novel route to improve electrochemical performances of layered materials through MED technique.

Breaking of Odd Chirality in Magnetoelectrodeposition of Copper Films on Micro-Electrodes

The surface chirality was investigated in magnetoelectrodeposition (MED) of copper films on micro-disc electrodes with the diameters of 100 and 25 µm. The MED was conducted in the magnetic fields of 1–5 T, which were parallel or antiparallel to the ionic currents. In the case of 100 µm-electrodes, the MED films prepared in 2 and 3 T exhibited odd chirality for the magnetic field polarity, as expected in the magnetohydrodynamic (MHD) vortex model. However, the films prepared in the higher fields of 4 and 5 T exhibited breaking of odd chirality. In the case of the 25 µm-electrode, the broken odd chirality was observed in 2 and 3 T. These results indicate that the strong vertical MHD flows induce the breaking of odd chirality. The mapping of chiral symmetry on the axes of the magnetic field and electrode diameter demonstrate that the odd chirality could be easily broken by the fluctuation of micro-MHD vortices.

Application of feed forward neural network model to predict the limiting current of tin magneto electrodeposition

Predicting the value of Tin Magneto electrodeposition (MED) is very important since the optimum mass transport occurred at the limiting current. The MED limiting current able to detect using electroanalytical chemistry, but this method is expensive; it needs some method, which able to predict the limiting current of tin MED. However, predicting the limiting current under magnetic field effect is more complicated due to the highly nonlinear characteristic and complicated of its multiple inputs single-output (MISO) system. The nonlinear model that able to predict the limiting current of tin MED is Artificial Neural Networks (ANNs). One of the ANNs which able to simulate the Multiple-Input-Single-Output (MISO) model is the Feed Forward Neural Network (FFNN). In this work, MISO FFNN will model a matrix data set with six variable inputs and one output. The data was obtained from the results of the experiments using electroanalytical chemistry. The output of this model is the limiting current of tin MED, meanwhile, the inputs are by the concentration of tin (Sn2+) in the electrolyte (C), viscosity(v), diffusion coefficient (D), area of the electrode (A), the number of electroactive species (n) and magnetic field strength (B). To get the best model, the performance of FFNN was tested with three variations of the algorithm (Levenberg-Marquardt, Bayesian Regularization, and Scaled Conjugate Gradient) and ten variations of the number of neurons (10, 15, 20, 25, 30, 35, 40, 45 and 50). The best model obtained for this MISO FFNN model is which uses the Levenberg-Marquardt algorithm and the highest number of neurons (50 neurons).

Fluctuation Effects of Magnetohydrodynamic Micro-Vortices on Odd Chirality in Magnetoelectrolysis

The magnetic field dependence of chiral surface formation was investigated in magnetoelectrodeposition (MED) and magnetoelectrochemical etching (MEE) of copper films. The MED and MEE was conducted in magnetic fields of up to 5 T, which were parallel or antiparallel to the ionic currents. The MED films prepared in high magnetic fields of 5 and 3 T exhibited odd chirality for magnetic field polarity, as expected on the basis of the magnetohydrodynamic (MHD) vortex model. However, the films prepared in the lower fields of 2.5 and 2 T exhibited breaking of odd chirality. Similar magnetic field dependence was observed in the surface chirality of MEE films. These results imply that the fluctuation in the self-organized state of micro-MHD vortices is responsible for the breaking of odd chirality.

Effects of Vertical MHD Flows and Cell Rotation on Surface Chirality in Magnetoelectrodeposition

The combination of vertical MHD flows and micro-MHD vortices can produce chiral surfaces in magnetoelectrodeposition (MED) of metals. Here we show two effects on the chiral surface formation in MED of copper. The first one is the effect of perturbation of vertical MHD flow using a tube wall around the electrode. The MHD flow penetrated into the tube and affected the chiral surface formation, as a result, the surface chirality depended on the height of wall. The other is the effect of rotation of electrochemical cell in magnetic fields. The rotational direction allowed the control of surface chirality.

Effects of Vertical Magnetohydrodynamic Flows on Chiral Surface Formation in Magnetoelectrolysis

Magnetoelectrolysis (electrolysis in magnetic fields) has potential to produce chiral surfaces on metal films. The Lorentz force causes two types of magnetohydrodynamic (MHD) flows; a vertical MHD flow and micro-MHD vortices, and the combination of these MHD flows has been considered to produce chiral surfaces. This paper shows the effects of vertical MHD flow on the chiral surface formation in magnetoelectrodeposition (MED) and magnetoelectrochemical etching (MEE) of copper films. To control the vertical MHD flows the working electrode was embedded in a tube wall with various heights of 2–12 mm, and the vertical MHD flows were expected to penetrate into the tubes with damping. In both MED and MEE experiments, the surface chirality diminished considerably at the wall height of 12 mm. When the penetrating MHD flow could not reach the electrode surface in the sufficiently tall wall, such an MHD flow could not affect the micro-MHD vortices. These results demonstrate that the vertical MHD flow plays a significant role in symmetry breaking of micro-MHD vortices.

Influences of magnetic field on the fractal morphology in copper electrodeposition

Copper magneto-electrodeposition (MED) is used decrease roughening in the copper electrodeposition process. This technology plays a vital role in electrodeposition process to synthesize metal alloy, thin film, multilayer, nanowires, multilayer nanowires, dot array and nano contacts. The effects of magnetic fields on copper electrodeposition are investigated in terms of variations in the magnetic field strength and the electrolyte concentration. Based on the experimental results, the mere presence of magnetic field would result in a compact deposit. As the magnetic field strength is increased, the deposit grows denser. The increment in concentration also leads to the increase the deposited size. The SEM image analysis showed that the magnetic field has a significant effect on the surface morphology of electrodeposits.

Effect of magnetic field on corrosion protection efficacy of Ni-W alloy coatings

High corrosion resistant Ni-W alloy coatings were developed using magnetoelectrodeposition (MED) approach for the protection of mild steel substrates. The conditions for the development of more corrosion resistant MED Ni-W alloy coatings were optimized by inducing a magnetic field (B) during deposition, in terms of intensity and direction. The applied magnetic field was used as a tool to alter the crystallinity, composition and thereby the corrosion resistance of the coatings. It was demonstrated that the corrosion resistance of Ni-W alloy coatings can be improved to many folds of its magnitude by MED approach. Significant increase in corrosion resistance exhibited by MED coatings (under both parallel and perpendicular magnetic field, B) is attributed to the increased W content of the alloy affected by an increase in limiting current density (iL). The high corrosion resistance of the MED Ni-W alloy coatings was explained in the light of magnetohydrodynamic (MHD) effect, responsible for the increased W content, brought about by the enhanced mass transport. The inherent limitations of the bath like low iL and induced type of codeposition which impedes the development of W rich alloy coatings has been successfully resolved by MED method. Drastic improvement in corrosion resistance is ascribed to the basic difference in the process of electrocrystallization and phases formed during MED, confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) study. The results are discussed with greater insight into binary alloy deposition and mass transfer process at cathode/electrolyte interface.

Optimization of Tin Magneto Electrodeposition under Additive Electrolyte Influence Using Taguchi Method Application

Operational conditions of tin magneto electrodeposition were successfully obtained using Taguchi technique. The parameters which optimize using Taguchi orthogonal array were tin sulphate, sulphuric acid, gluconate concentrations and magnetic strength (Tesla). The gluconate in this process is additive electrolyte which acts as an inhibitor against corrosion. The effects of those parameters toward the fractal dimension of tin electrodeposits were studied in this research. The results show that microstructures of tin electrodeposit from magneto electrodeposition have a compact structure than the tin electrodeposits of conventional electrodeposition.

Magnetoelectrodeposition of Ni–W alloy coatings for enhanced hydrogen evolution reaction

The electrocatalytic efficiency of electrodeposited (ED) Ni–W alloy coatings for the hydrogen evolution reaction (HER) has been improved drastically through magnetoelectrodeposition (MED) approach.

Magneto-electro deposition of tin dendrites

The magnetic strength and number of electrons in tin magneto-electro deposition can induce the limiting current by increasing the mass transport of electro active species. The presence of the magnetic field can lead to the eventual increase of the electrolytic current by means of convective movement of the electro active species. In this paper, the growth of tin dendrites under the magnetic field is reported. The results show that the deposited mass (coating) and fractal dimension increase in the presence of the magnetic field from a simulation (based on the diffusion limited aggregation) and an experiment.

Development of Semi Empirical Equation of Limiting Current for Lead (Pb) Magneto Electrodeposition

An electrodeposition process placed in a magnetic field or magneto electrodeposition (MED) cause the increment of limiting current and the change of electrodeposits become more compact. This method is important process to produce of nano materials and micro electronics devices. Knowing the limiting current in electrodeposition process is very important because the optimum mass transport achieve at this condition. This limiting current under magnetic influence (iB) can be predict accurately using semi empirical equation, which have parameters that influence on mass transport phenomena on MED. The semi empirical expression of iB for lead (Pb) MED was established for our experimental setup.