Pulse Electrodeposition Process Research Articles

Cu-based bubble and ion sieve for ampere-level hydrogen evolution

Designing cheap, efficient, and stable electrocatalysts for hydrogen evolution reaction (HER) under ampere-level current density is essential for the industrial water electrolysis technique. However, the large H2 bubbles produced at high current density decrease the activity and stability of the catalyst. Here, a self-supported electrode with porous yolk-shell CuNi@Cu electrocatalyst is obtained via an alternant electrodeposition and replacement reaction during the pulse electrodeposition process. The porous Cu shell can boost electrolyte diffusion and serve as an H2 bubble fining sieve to enhance the activity and stability of alkaline HER at high current density with the low overpotential of 326 mV @1 A cm−2. The CuNi@Cu electrocatalyst can work steadily for 1000 h at 1 A cm−2 with negligible attenuation. The porous Cu shell can also repel cations in natural seawater owing to the positively charged surface. The spontaneous alternant reaction paves an avenue to design electrocatalysts with porous yolk-shell structures for large-scale industrial applications.

Chitosan/Graphene Oxide Nanocomposite Coatings on Magnesium Alloy: Corrosion and Biocompatibility Properties

Abstract In the present study, optimal conditions for the fabrication of chitosan (CS)/graphene oxide (GO) nanocomposite coatings were evaluated by the pulse electrodeposition (PED) process on Mg–2wt%Zn scaffolds. The size distribution of CS, GO suspension, and CS/GO composite was evaluated using dynamic light scattering. The coatings’ microstructure and morphologies were investigated by Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, thermogravimetric analysis, derivative thermogravimetric analysis, differential thermal analysis, and scanning electron microscopy. The Taguchi statistical method was used to optimize PED parameters, including peak current density (j), duty cycle, and GO nanosheets content (1, 2, and 3 percent by weight [wt%]). Results showed that optimal coatings were produced under the conditions of 2 wt% GO, j = 20 mA/cm2, duty cycle = 0.5, and pH = 5. The process’s time, temperature, and frequency were 20 min, 37°C, and 1,000 Hz. The biocompatibility of coatings was assessed by in vitro test. The results of cell viability and adhesion of MG63 cells on optimal coating are promising for application in bone tissue engineering.

Nanostructured MnO2 Films for 3D Micro‐Supercapacitors: From New Insights of the Growth Mechanism to the Fine Tuning of Areal Capacitance Values

Maximizing the electrochemical performance of 3D micro-supercapacitors based on pseudocapacitive films is crucial for powering the next generation of miniaturized IoT devices. The films have to be nanostructured, must conform the 3D template, and have uniform deposition. To study the growth mechanism of nanostructured MnO2 films obtained by a pulsed electrodeposition method, in situ Atomic Force Microscopy methods operating in liquid mode, Scanning Electron Microscopy, and electrochemical characterization techniques were used. The impact of ON and OFF times during the pulsed electrodeposition process was investigated. The deposition mechanism in Volmer Weber Island growth mode provided some guidelines to tune the deposit morphology to enhance the electrochemical performance of the 3D electrode based on nanostructured MnO2 films.

Electrical property-microstructure of copper interconnects printed by localized pulsed electrodeposition (l-PED)

Printing processes that enable printing high conductivity metals at small scale (<mm) are in demand for microelectronics, interconnects, and sensors applications. Since electrical properties of metals are controlled by their microstructure, microstructure-property relation for each process needs to be established. In the recently developed localized pulsed electrodeposition (l-PED) process, the pulsed voltage applied during metal printing allows control over the microstructure. In this article, we quantify the electrical resistivity of copper (Cu) interconnects printed by the l-PED process and correlate it with its microstructure. The results show a microstructure combined of nanotwinned (nt) grains and nanocrystalline (nc) grains, with an average grain size of 190 nm and twin thickness of ∼8 nm to ∼29 nm. The electrical resistivity was measured to be 8.25 µΩ.cm, which correlates with the observed microstructure and is remarkable for a printing process with no post-processing annealing done on the printed metal.

Pulse-electrodeposited Ni–Fe–Sn films supported on Ni foam as an excellent bifunctional electrocatalyst for overall water splitting

The development of extremely active bifunctional non-noble electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is pivotal for water splitting but remains challenging. Herein, self-supported Ni–Fe–Sn electrocatalysts were fabricated on nickel foam (NF) through a simple and facile pulse electrodeposition process. Under optimal conditions, the prepared Ni–Fe–Sn electrocatalysts exhibited excellent bifunctional properties in alkaline medium and required ultralow overpotentials of only 27 and 201 mV for HER and OER, respectively, to reach the current density of 10 mA cm−2. Importantly, the same Ni–Fe–Sn electrocatalyst can be assembled as the anode and the cathode in a two-electrode system. It demanded a fairly low applied voltage of 1.55, 1.72, and 1.87 V to produce 10, 50, and 100 mA cm−2, respectively, and exhibited excellent long-term stability. The excellent electrocatalytic water splitting performance of the Ni–Fe–Sn film was mainly associated with its intrinsic catalytic activity derived from the modulation of the electronic structures among Ni, Fe, and Sn by using the appropriate atomic ratio of Ni: Fe: Sn.

Superhydrophobic micro-nano structured PTFE/WO3 coating on low-temperature steel with outstanding anti-pollution, anti-icing, and anti-fouling performance

The fabrication of superhydrophobic coatings on the low-temperature steels has rarely been explored to this day. Herein, we designed and fabricated a superhydrophobic micro-nano structured composite coating on the E40 low-temperature steel, which was composed of an underlying WO3 coating derived from the pulsed electrodeposition process and a top polytetrafluoroethylene (PTFE) layer obtained from the magnetron sputtering. The synergistic effect of the hierarchical micro-/nanostructures of the WO3 coating and the low surface free energy of the fluorine-containing PTFE layer makes the PTFE/WO3 coating superhydrophobic, which demonstrated a water contact angle of 159° and a water roll-off angle of ≤1°. The PTFE/WO3 coating exhibited outstanding anti-pollution properties towards both the solid pollutant such as carbon black particles and the liquid pollutant such as black ink. Importantly, the PTFE/WO3 coating demonstrated excellent anti-icing properties with low icing temperature and small ice-adhesion strength, while simultaneously possessing outstanding anti-fouling performance. The present work provides a new strategy for fabricating coatings with multifunctionality on metallic materials which can work under low-temperature and biofouling conditions.

Application of BP Artificial Neural Network in Preparation of Ni-W Graded Coatings.

The internal stress difference between soft-ductile aluminum alloy substrate and hard-brittle Ni–W alloy coating will cause stress concentration, thus leading to the problem of poor bonding force. Herein, this work prepared the Ni–W graded coating on aluminum alloy matrix by the pulse electrodeposition method in order to solve the mechanical mismatch problem between substrate and coatings. More importantly, a backward propagation (BP) neural network was applied to efficiently optimize the pulse electrodeposition process of Ni–W graded coating. The SEM, EDS, XRD, Vickers hardness tester and Weighing scales are used to analyze the micromorphology, chemical element, phase composition, and micro hardness as well as oxidation weight increase, respectively. The results show that the optimal process conditions with BP neural network are as follows: the bath temperature is 30 °C, current density is 15 mA/cm2 and duty cycle is 0.3. The predicted value of the model agrees well with the experimental value curve, the relative error is minor. The maximum error is less than 3%, and the correlation coefficient is 0.9996. The Ni–W graded coating prepared by BP neural network shows good bonding with the substrate which has flat and smooth interface. The thickness of the coating is about 136 μm, which slows down the oxidation of the substrate and plays an effective role in protecting the substrate.

Preparation and characterization of chitosan/graphene oxide nanocomposite coatings on Mg–2 wt% Zn scaffold by pulse electrodeposition process

Mg and its alloys are biodegradable and mechanically strong materials, which can be used for an orthopedic implant and device applications, but corrosion rate of these alloys is high. In this research, the nanocomposite coatings of chitosan (CS)/graphene oxide (GO) were fabricated to improve the corrosion resistance of the Mg–2 wt% Zn scaffold. The contents of the GO nanosheets and the pulse electrodeposition process parameters, including peak current density (CD) and duty cycle (DC), will also be investigated. The Mg–2 wt% Zn as a substrate of the scaffold was prepared using a powder metallurgy process. The influence of the porosity was studied on the microstructure fabricated scaffolds. The coating microstructures and morphologies were investigated by Raman spectroscopy, x-ray diffraction, thermogravimetric analysis, and SEM. The atomic force microscopy was performed to study the thickness of the nanocomposite coatings. The zeta potential measurement was conducted for the dispersion of the GO nanosheets in the CS matrix. The obtained results showed that the optimum conditions to fabricate a uniform CS/GO coating on the scaffolds were 2 wt% GO, CD = 20 mA cm−2, and DC = 0.5. The pH, time and temperature for the fabrication of the coatings were conducted at 5, 20 min, and 37 °C, respectively. Additionally, the potentiodynamic polarization measurement in simulated body fluid indicated that the CS/GO coatings could provide effective protection of the scaffolds against corrosion. Additionally, the optimum sample obtained from the aspect of the corrosion behavior demonstrated adequate biocompatibility with proper adhesion of mouse fibroblast cells (L929) on the CS–2 wt% GO coating.

Effect of concentration of TiC on the properties of pulse electrodeposited Ni–P–TiC nanocomposite coatings

Ni–P/TiC nanocomposite coatings, including different concentrations of TiC nanoparticles (TCNPs) were developed on HSLA (high strength low alloy steel) substrates through the pulse electrodeposition (PED) process. The prepared coatings' structural, compositional, mechanical, wear, and electrochemical properties were accomplished, applying numerous characterizing techniques. The surface morphologies show the coatings are uniform, and compact, which appears flawless. An increase in the mechanical response of Ni–P/TiC is noticed with an increasing amount of TCNPs into the Ni–P matrix, attaining its highest values (720 Hv microhardness, 22.22 GPa modulus, 7.26 kN/m stiffness), and the lowest wear rate (ws) of 0.87 μ gm/Nm) for Ni–P/0.75TiC composition. The improvement in mechanical behavior can be attributed to grain refinement and dispersion hardening effect. Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic plots reveal a substantial increment in Ni–P coatings' corrosion resistance by successively incorporating TCNPs. As a comparison, Ni–P/0.75TiC coatings demonstrate the highest corrosion protection requirement efficiency (PE) of 94% in saline water. The promising performance of Ni–P/0.75TiC coating can be credited to forming a compact structure containing inactive TCNPs in the Ni–P matrix.

Pulsed electrodeposition of Ni-B/TiN composites: effect of current density on the structure, mechanical, tribological, and corrosion properties

ABSTRACT Ni-B/TiN composite coatings with different current densities (1.5, 3.0, 4.5, and 6.0 A/dm2) have been successfully produced on a mild steel substrate using the pulsed electrodeposition (PED) method. The effect of current density on structure, morphology, hardness, tribological, and corrosion behaviors were investigated. It was found that the composite coating produced with a current density of 4.5 A/dm2 exhibited, smooth surface a uniform fine compact and crack-free structure and the particles were distributed homogeneously in the metallic matrix. After the Ni-B/TiN composite coatings deposited on the substrate, samples were heat treated at 400 C for 1 h for providing precipitation of intermetallics to improve mechanical and tribological properties. In the electrochemical measurements performed in 3.5% NaCl solution by weight, the anti-corrosion ability of the composite coating was analyzed. According to the results obtained that current density is an important parameter affecting not only the deposition mechanism of Ni-B/TiN composite depositions but also microstructural, mechanical, tribological, and corrosion properties in the PED process. Accordingly, TiN particle reinforced Ni-B composite coatings deposited by the PED method are expected to be applied as a protective coating in industrial applications with excellent hardness, superior wear resistance and anticorrosion capability.

Thermal stability of microscale additively manufactured copper using pulsed electrodeposition

Micro/nanoscale 3D printing of metals is promising for printed electronics and sensors. It is important to evaluate how material properties of the microscale 3D-printed metals change at high temperature, though such studies are currently very limited. Here, we investigate morphological and mechanical property changes in copper interconnects 3D-printed by pulsed electrodeposition process. The results revealed significant surface damage and void formation in printed Cu after annealing at 450 °C. No significant surface damages or voids were observed for printed Cu annealed at 300 °C, however, their strength dropped ~40% from the strength of the as-deposited material (~868 MPa). Such results are important to determine the operation temperature range for interconnects fabricated by microscale 3D printing.

Using DMH as a complexing agent for pulse electrodeposition of platinum nanoparticles towards oxygen reduction reaction

Due to the excellent intrinsic activity of platinum, developing a Pt-based oxygen reduction catalyst with both high performance and low loading is highly desirable but still challenging. How to improve the utilization of platinum-based materials has become one of the most critical issues. Herein, a synthesis strategy using the 5,5-dimethylhydantoin (DMH) as complexing agent is designed to synthesize the Pt catalyst via pulse electrodeposition. On the one hand, the platinum nanoparticles prepared by electrodeposition are exposed on the surface of support materials, which effectively avoids performance degradation caused by the coverage of binder and support. On the other hand, the strong coordination affinity between DMH and platinum ions significantly inhibits the electrodeposition process, resulting in a smaller size of platinum nanoparticles. The effect of plating composition and pulse plating parameters on the Pt/KB catalyst activity for oxygen reduction reaction (ORR) has been investigated. The deposited Pt nanoparticles show a face-centered cubic (fcc) crystal structure with a size ranging from 3 to 10 nm. The optimized Pt/KB catalyst exhibits an enhanced activity (i.e., a half-wave potential of 0.906 V) and stability in the acidic media, even with lower loading of platinum. Moreover, the vital role of the DMH in the pulse electrodeposition process is further verified by using linear sweep voltammetry and cyclic voltammetry.

Preparation of Co–P–TiO2 nanocomposite coatings via a pulsed electrodeposition process

ABSTRACT A series of Co–P–TiO2 nanocomposite coatings were prepared via pulsed electrodeposition technique. TiO2 nanoparticles were embedded into the coating matrix using TiO2 sol. The phase constituents of nanocomposites were identified using X-ray diffraction. The surface morphology of nanocomposites was obtained through scanning electron microscopy. Wear tests and corrosion tests were conducted to determine the coating performance. Electrochemical characterization was performed by electrochemical impedance spectroscopy analysis. The nanocomposite coatings made via conventional pulse electrodeposition had a relatively ordered surface morphology and enhanced mechanical behaviour, which is associated with the increased strengthening effect of embedded nanoparticles. When applying a pulse reverse current, the Co–P–TiO2 nanocomposite coating had improved corrosion resistance owing to its smooth and uniform surface morphology.

Effect of Pulse Parameters on The Particle Size of Copper Powder Electrodeposition

In this paper, copper powder fabrication has been made via electrolysis method using CuSO4 and H2SO4 in aqueous media. Electrodeposition process of copper powder on a metallic surface is done by applying to continue current and pulse current with rectangular pulse waveform. Characterization of copper powder was carried out by SEM to confirm particle size and shape and EDX to determine the copper powder composition. In electrodeposition by applying to continue current to produce the copper powder with particle shape was dendritic, and the elemental composition of the powder was Cu and O. Regarding average particle size, pulse electrodeposition process produces the copper powder with average particle size up to 0.85μm, 72.6% smaller than if apply to continue current.

Mechanism and kinetic study of pulse electrodeposition process of Pt/C catalysts for fuel cells

The growth mechanism and the corresponding kinetic parameters are valuable to improve the electrodeposition method for preparing Pt-based catalysts. In this paper, the effect of the operation condition on the electrodeposition mechanism has been investigated through experiments and theoretical analysis, and the corresponding kinetic parameters were acquired. The catalytic activity of the deposited Pt catalyst prepared by the pulse current (PC) electrodeposition method was improved, compared with that of the commercial Pt catalyst and the Pt catalyst prepared by the direct current electrodeposition method. The results show that both high current density and high ton/toff in PC electrodeposition could cause large cathode overpotentials, resulting in faster nucleation rate and smaller catalyst particle size, which leads to the better reaction activity of the Pt catalyst. Finally, kinetic parameters including the constants, which relate the nucleation rate with the overpotential, the transfer coefficient and the exchange current density of the electrodeposition process, were determined.

Pulse electrodeposited RuO2 electrodes for high-performance supercapacitor applications

ABSTRACTThe present work addresses high-performance Ruthenium Oxide (RuO2) electrodes prepared by using a simple pulse electrodeposition method. For the comparison purpose, two different precursors, namely, ruthenium (III) nitrosyl sulphate (RuNS) and ruthenium trichloride (RuCl3), were used in this study. The coatings were subjected to material characterisation such as Field Emission Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy, X-ray diffraction and Transmission electron microscopy as well as electrochemical characterisation such as Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and charge/discharge. The RuNS–RuO2 coating exhibited excellent specific capacitance (1724 F/g at 5 A/g) with a remarkable rate capability. This value is significantly higher (52%) than the value obtained for RuCl3–RuO2 electrode material at 5 A/g. The findings provide valuable information on the potential use of RuNS as a precursor for synthesising RuO2 and pulse electrodeposition process to produce electrodes for supercapacitors.

Toward Control of Microstructure in Microscale Additive Manufacturing of Copper Using Localized Electrodeposition

The progress in microscale additive manufacturing (μ‐AM) of metals requires engineering of the microstructure for various functional applications. In particular, achieving in situ control over the microstructure during 3D printing is critical to eliminate the need for post‐processing and annealing. Recent reports have demonstrated the possibility of electrochemical μ‐AM of nanotwinned metals, in which the presence of parallel arrays of twin boundaries (TBs) are known to enhance mechanical and electrical properties. For the first time, the authors report that the microstructure of metals printed using the microscale localized pulsed electrodeposition (L‐PED) process can be controlled in situ during 3D‐printing. In particular, the authors show that through electrochemical process parameters the density and the orientation of the TBs, as well as the grain size can be controlled. The results of the in situ SEM microcompression experiments on directly 3D‐printed micro‐pillars show that such control over microstructure directly correlates with the mechanical properties of the printed metal.

Reversed Pulse Plating of Silver-Cobalt for Connector Applications

Abstract The manuscript describes the use of anti-galling silver-cobalt alloy as a novel metallic contact finish for connector applications. The purpose of this work was to develop a cost-effective and cyanide-free and self-lubricated silver-cobalt alloy deposited using reversed pulse electrodeposition process for silver-based contact finishes in electrical contacts applications. The manuscript describes a novel silver-cobalt alloy deposited through reversed pulse-electroplating process that provides exceptionally low friction coefficient (similar to hard gold) and outstanding wear resistance compared to standard silver and any commercially available electroplated silver alloys such as silver-tin, silver palladium, silver antimony, silver-bismuth, silver-tellurium, and silver-tungsten.

Investigation of Carbon Nanofiber‐supported Electrocatalysts with Ultra‐low Platinum Loading for the Use in PEM Fuel Cells

AbstractThe present study aims to investigate gas diffusion electrodes with ultra‐low platinum loading and increased durability, prepared by pulsed electrodeposition process, applicable for polymer electrolyte membrane fuel cells (PEMFC). Testing was performed both, in situ in a PEMFC test bench while prepared GDEs were compared to anodes and cathodes with commercially available catalysts by Johnson Matthey (JM), as well as ex situ regarding electrochemical properties and catalyst layer structure. High and stable performance of developed electrodes was achieved, while the Pt catalyst loading of investigated anodes and cathodes was reduced to 10 µgPt cm−2. The catalyst deposition was achieved via pulsed electrodeposition process from H2PtCl6‐containing electrolyte on an oxygen plasma‐pretreated corrosion‐stable carbon nanofiber (CNF) support. In situ performance tests show a similar operation behavior of the compared anodes, while activation losses of investigated cathodes are high due to the limited amount of catalyst material. However, Pt/CNF_c cathodes show significantly higher power densities than cathodes prepared with JM catalyst. Membrane electrode assemblies containing developed Pt/CNF_a anodes with 10 µgPt cm−2 reached a power density of 0.525 W cm−2 at a cell potential of 0.65 V, which was similar to anodes with commercially available HiSPEC 2000 catalysts by JM. Accelerated stress tests (AST) revealed that Pt/CNF_a anodes preserve their performance, whereas the commercial catalyst degraded severely. Cyclic voltammetry (CV) indicated a high electrochemical active surface area of Pt/CNF_a anodes. Moreover, the electrode characteristics, analyzed via electrochemical impedance spectroscopy after AST, showed marginal anode degradation.

Pulse Reverse Plating of Silver on Silver Alloy

Pulse deposition is a scalable and easy technique to obtain uniform coating without voids. In this work, the electrodeposited silver on silver alloy by pulse–reverse pulse and DC electrodeposition process. The quality of the film was analyzed by various characterization techniques. The structural property was studied by XRD, nitrogen adsorption studies and atomic force microscopy techniques. The electrical and chemical property of the film was analyzed by electrochemical techniques.