Current Electrodeposition Research Articles

Enhancing NiCoB alloy coatings with hBN nanoparticles: exploring structural, mechanical, and corrosion improvements through pulse electrodeposition

ABSTRACT NiCoB/hBN composite coatings deposited onto a 304 stainless steel substrate by pulsed current electrodeposition method. The morphology, chemical composition, structural, mechanical and corrosion properties of the coatings were investigated. Optimal microhardness, corrosion resistance, and a lower coefficient of friction were achieved when the hBN concentration in the plating bath was 8 g L−1 . Vickers microhardness increased from 610 to 980 HV and the coefficient of friction decreased from 0.53 to 0.4. Grain size decreased as the amount of added hBN increased, affecting the microstructure of the coating. Increasing the concentration of hBN in the plating solution increased the percentage of hBN particles in the film, reducing the percentage of total metal from 95.18% to 89.76%. The magnitude of the Nyquist parabola of the composite film from the bath containing 8 g L−1 hBN increased by an average of 5 times compared to that of the NiCoB metal alloy film.

Preparation and Properties of Thick Tungsten Coating Electrodeposited from Na2WO4-WO3-KCl-NaF Molten Salt System

The pulsed current electrodeposition method was employed for the first time to achieve tungsten coating with a thickness of 433.72 μm on a CuCrZr alloy from Na2WO4-WO3-KCl-NaF molten salt. The microstructure of the coating was observed and the coating density, porosity, hardness, bonding strength, residual stress and oxygen content were tested. The results revealed that the tungsten coating exhibited desirable characteristics such as high density, absence of impurities, excellent adhesion to the matrix (53.16 MPa), residual compressive stress as surface stress, and good stability and durability. Moreover, this thick tungsten coating possesses high density and hardness, low oxygen content and porosity. This offers a novel solution to solve the challenging issue of the connection between tungsten material and heat sink material.

Interdependence of Support Wettability ‐ Electrodeposition Rate‐ Sodium Metal Anode and SEI Microstructure

AbstractThis study examines how current collector support chemistry (sodiophilic intermetallic Na2Te vs. sodiophobic baseline Cu) and electrodeposition rate affect microstructure of sodium metal and its solid electrolyte interphase (SEI). Capacity and current (6 mAh cm−2, 0.5–3 mA cm−2) representative of commercially relevant mass loading in anode‐free sodium metal battery (AF‐SMBs) are analyzed. Synchrotron X‐ray nanotomography and grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) are combined with cryogenic ion beam (cryo‐FIB) microscopy. Highlighted are major differences in film morphology, internal porosity, and crystallographic preferred orientation e.g. (110) vs. (100) and (211) with support and deposition rate. Within the SEI, sodium fluoride (NaF) is more prevalent with Te−Cu versus sodium hydride (NaH) and sodium hydroxide (NaOH) with baseline Cu. Due to competitive grain growth the preferred orientation of sodium crystallites depends on film thickness. Mesoscale modeling delineates the role of SEI (ionic conductivity, morphology) on electrodeposit growth and onset of electrochemical instability.

Interdependence of Support Wettability - Electrodeposition Rate- Sodium Metal Anode and SEI Microstructure.

This study examines how current collector support chemistry (sodiophilic intermetallic Na2Te vs. sodiophobic baseline Cu) and electrodeposition rate affect microstructure of sodium metal and its solid electrolyte interphase (SEI). Capacity and current (6 mAh cm-2, 0.5-3 mA cm-2) representative of commercially relevant mass loading in anode-free sodium metal battery (AF-SMBs) are analyzed. Synchrotron X-ray nanotomography and grazing-incidence wide-angle X-ray scattering (GIWAXS) are combined with cryogenic ion beam (cryo-FIB) microscopy. Highlighted are major differences in film morphology, internal porosity, and crystallographic preferred orientation e.g. (110) vs. (100) and (211) with support and deposition rate. Within the SEI, sodium fluoride (NaF) is more prevalent with Te-Cu versus sodium hydride (NaH) and sodium hydroxide (NaOH) with baseline Cu. Due to competitive grain growth the preferred orientation of sodium crystallites depends on film thickness. Mesoscale modeling delineates the role of SEI (ionic conductivity, morphology) on electrodeposit growth and onset of electrochemical instability.

Resistance to Electrical Corrosion of Au-Cu Alloy Coatings for Electronic Contacts

In order to obtain electronic contacts with good performance, Au-Cu alloy coatings with different gold contents were prepared on copper substrates by direct current electrodeposition and were tested against electrochemical corrosion and arc corrosion. The experimental results showed that the hardness of the Au-Cu alloy was in the range of 115.2 HV~171.6 HV, which meets the requirements of electronic contact materials. The polarization curve (Tafel) test and electrochemical impedance spectroscopy (EIS) test results indicated that the electrochemical corrosion resistance of Au-Cu alloy plating was much better than pure copper. With the rise of gold content in the alloy coatings, the corrosion resistance of the alloy coatings enhanced gradually. Compared with pure copper, the Au-Cu alloy coatings showed more stable contact resistance. After 1000 contacts, the resistivity of the alloy with 75% gold varied from 72 mΩ to 78 mΩ, whereas under the same conditions, the resistivity of copper changed from 14 mΩ to 78 mΩ. Anode-type material transfer occurred after 1000 contacts with a reduction in the total mass of each contact element. The mass loss of Au75Cu25 and Au86Cu14 contact elements was lower than that of pure copper. The Au-Cu alloy coatings displayed excellent arc corrosion resistance when the gold content in the alloy plating was higher than 75%.

The effect of multi-step cycles on the surface properties of Ni-TiO2 coatings produced by pulse current electrodeposition

ABSTRACT In this study, the Ni-TiO2 coatings were deposited on copper substrates by pulse plating. The effect of multi-step current cycles on the metallurgical properties of produced coatings was investigated. The results showed that the values of applied currents within the periods significantly affect the surface properties of all coatings. Using the negative current cycles, the surface morphologies completely changed from regular and compact to irregular, compared to the deposits that did not have a negative cycle in the coating process. Also, the surface roughness increased by 1.5 times in the best case. Applying the 8-step cycle increased the percentage of TiO2 content inside the Ni-TiO2 layer from 13.13 vol.% to 31.58%. The corrosion and wear analysis results showed that the coating applied by a 4-step cycle with a 90-second off time has the best properties. Therefore, the corrosion and wear properties were not necessarily directly related to the participation percentage of TiO2 particles. Compact morphology with high current efficiency, wide distribution of TiO2 particles (6.31 vol.%) with minimal agglomeration, low coating roughness (Ra = 0.32 µm), high hardness value (436 Vickers), and the participation of (111) plane in the preferred texture improved the corrosion and wear behaviour of the optimal coating.

Bisphenol A Polyoxyethylene Ether Sodium Sulfate as a New Leveler for Electrodeposition of Copper.

The electrochemical behavior of three types of bisphenol A polyoxyethylene ether sodium sulfate (BPA) is investigated through cyclic voltammetry striping tests. The results indicate that BPA-25 exhibited the most significant inhibition of Cu deposition. The nanotwinned Cu (nt-Cu) films are prepared by direct current electrodeposition in an acidic Cu sulfate bath containing a combination of conventional bath additives. Transmission electron microscopy (TEM) and cross-sectional scanning electron microscopy (SEM) results revealed that nt-Cu consisted of microcolumnar grains with high-density nanoscale coherent twin boundaries oriented parallel to the growth surface. The interaction between BPA-25 and the poly2-sulfur-2-propane sodium sulfonate (SPS) was further analyzed through galvanostatic measurements (GMs) and electron backscatter diffraction (EBSD). The results demonstrate that BPA-25 and SPS underwent competitive adsorption on the cathode surface, leading to the formation of nt-Cu. This growth mechanism provides a new perspective for the preparation of nt-Cu by using direct current electrodeposition.

Electrodeposited zinc cobalt bimetallic phosphate as a bifunctional catalyst for hydrogen evolution and urea oxidation

The theoretical potential of the urea oxidation reaction (UOR) is a mere 0.37 V(vs.RHE), significantly lower than the 1.23 V (vs. RHE) of the oxygen evolution reaction (OER). Thus, substituting the OER with the UOR can effectively reduce the voltage required for electrolysis. Transition metal phosphates (TM-Pi), with their unique physical properties, can partly replace precious metal catalysts and hold great application potential. However, further modification is necessary to enhance their catalytic activity and stability. Therefore, this study prepared a coral-like cluster Co/Zn-Pi@NF (Pi represents phosphate) catalyst, which was grown in situ on nickel foam (NF) using the constant current electrodeposition method. The catalyst exhibited superior catalytic performance in 1 M KOH, with the required overpotentials for the hydrogen evolution reaction (HER) and OER reaching 10 mA·cm−2 being 36.6 mV and 343.4 mV, respectively. In 1 M KOH containing 0.5 M urea, the urea oxidation potential was only 1.4 V, which remained stable for 60 hours. The Co/Zn-Pi@NF nanoparticles were used as the anode and cathode for water-urea electrolysis, and the electrolysis voltage was 1.43 V at a current density of 10 mA·cm−2, which was 290 mV lower than that of electrolyzed water. This study demonstrates that zinc-cobalt bimetallic phosphate can be used as a dual-function electrocatalyst for hydrogen evolution and urea oxidation.

Effect of Tween 80 on the Electrocatalytic Performance of a Ti/PbO2‐MWCNTs Electrode

AbstractIn this work, Ti/PbO2‐MWCNTs anodes modified with different amount with different amount of Tween 80 (0.0–2.0 g/L) were prepared by the direct current electrodeposition method used as anode materials for Zinc electrowinning. The MWCNTs were dispersed in a lead nitrate solution with Tween 80, and the effects of the amount of added Tween 80 on the morphology, phase composition and electrocatalytical performance of lead dioxide coating were investigated. Physical characterizations show that with the increase of the amount of Tween 80, both grain size of PbO2 and carbon content in PbO2 layer firstly increased and then decreased, the preferential orientation and crystallinity of the PbO2 grain growth in the deposition process changed. Electrochemical tests demonstrate that the optimal modified electrode achieved the minimum Eo value and maximum j0 of 2.038 V and 3.781×10−4 A, respectively, an increase of capacitance to 368.8 μF cm−2, and a decrease of charge transfer resistance to 92.74 Ω cm2, which is mainly attributed to the PbO2 electrode modified with Tween 80, coupled with the synergistic effects of MWCNTs doping.

Magnetic properties of bamboo-like Ni-Zn-in nanowires using 3D-AAO templates

In this paper, using three-dimensional porous alumina (3D-AAO) as a template, Ni-Zn-In nanowires array with periodically changing diameters was successfully prepared by direct current electrodeposition method. The effect of deposition voltage on the morphology, crystal structure and magnetic properties of Ni-Zn-In ternary alloy nanowires was studied. The experimental results show that the diameters of the nanowires are 212 nm and 151 nm, and the periodic length is 800 nm, which matches the pore size of the phosphoric acid-etched 3D-AAO template. XRD results indicate that the crystal structure of Ni-Zn-In nanowires can be adjusted by the deposition voltage. The VSM results reveal that the Ni-Zn-In nanowires possess soft magnetic properties and significant magnetic anisotropy, with the easy magnetization direction parallel to the film. The nanowires deposited at −1.5 V exhibit the highest coercivity of 161 Oe and squareness of 0.045. Micromagnetic simulations show that the magnetization reversal mechanism of the Ni-Zn-In nanowires is localized nucleation mode.

Electrodeposition of Ni–MoS2 as effective hydrogen evolution reaction catalysts in alkaline media

Highly active, long-lasting, and economically feasible nonprecious metal-based electrocatalysts are urgently required for the slow hydrogen evolution reaction (HER) in alkaline conditions. Direct current (DC) electrodeposition was used to develop the highly active Ni–MoS2 composite coatings for efficient hydrogen generation. Scanning electron microscopy (SEM), Energy Dispersive X Ray Spectroscopy (EDS), X-ray diffraction (XRD), and linear sweep voltammetry (LSV) were used to evaluate the coatings. Ni–MoS2 composite coatings behaved almost identically to pure platinum metal. The Ni–MoS2 coating produced 1.0 g/l demonstrated a low overpotential for HER. The HER process's analyzed from Volmer-Tafel mechanistic route has an extremely low slope of 56.5 mV/dec. All the coated samples were subjected to chronopotentiometry (CP). This catalyst's high HER performance shows that it has significant potential for practical applications.

Pulsed electroplating of ZrO2-reinforced Ni-Cr alloy coatings from the duplex complexing agents-containing bath for engineering applications: Importance of operating conditions

The progress in tribocorrosion performance of the engineering parts is in dire need of improving their surface properties. In the present contribution, Ni-Cr-ZrO2 layers were electrodeposited on St37 steel. The stress was put on optimizing the process factors, including the parameters involved in pulsed current electrodeposition and level of the ZrO2 reinforcing nanoparticles (0–20 g/L) in the bath. The surface characteristics of the electrodeposits were evaluated using FESEM, EDS, AFM, and XRD. The tribomechanical characteristics of the films were determined using a Vickers microhardness tester and pin-on-disk apparatus. The electrochemical behavior of the samples was studied using OCP, EIS, PDP, and immersion techniques. The results demonstrated that the included ZrO2 nanoparticles led to more homogenous, rougher, and defect-free surfaces, while they did not change the phase composition of the alloy electrodeposits. The polarization resistance of the Ni-Cr alloy coating increases by 6.7 times when 10 g/L of the reinforcing nanoparticles is added to the electrolyte. A decrease of ≈42 % in the mean COF value was obtained by the incorporation of 10 g/L ZrO2 nanoparticles into the plating bath. The coating system developed holds the promise to address both technical requirements and health concerns.

Microstructure, hardness, and tribological properties of Ni-Co/ SiO2 nanocomposite coating produced through pulsed current electrodeposition

This study investigates the development of Ni-Co/SiO2 nanocomposite coatings on mild steel surface using pulsed-current electrodeposition method. The effects of incorporating SiO2 nanoparticle and varying its concentration on the coatings' microstructure, microhardness, wear resistance, and frictional properties were assessed using field-emission electron microscopy, X-ray diffraction, Vickers microhardness testing, and dry sliding wear tests. The results indicated that the coatings exhibited two-phases of Ni-Co solid solution (α) with a face-centered cubic (FCC) crystal structure and hexagonal Co, a refined crystallite size of approximately 31 nm for Ni-Co and about 25 nm for Ni-Co/SiO2, along with a colony-like morphology that did not show any preferred growth direction. The amount of Ni-Co solid solution increased with the addition of SiO2 nanoparticles. The composite coatings demonstrated enhanced microhardness of 581 HV, which is 52 % greater than that of the Ni-Co coating, as well as improved wear resistance and a reduced friction coefficient compared to the unreinforced alloy coating. However, higher SiO2 content adversely impacted the tribological properties due to nanoparticle agglomeration. Analysis of the worn surfaces revealed a transition from abrasive wear to oxidative wear with increasing applied force for the coatings.

Binder-free copper manganese sulfide nanoflake arrays electrodeposited on reduced graphene oxide-wrapped nickel foam as an efficient battery-type electrode for asymmetric supercapacitors

In the current study, 2D interconnected copper manganese sulfide (CMS) nanoflake arrays are successfully electrodeposited on nickel foam (NF) and reduced graphene oxide-coated NF (NF/rGO). A pulsed current electrodeposition method is used to prepare a uniform and homogeneous coverage of rGO on NF. By using rGO as a conductive carbon-based template, an ultrathin nanoflake structure of CMS with smaller dimensions and higher electrochemically active surface area (ECSA) is achieved. The results reveal the battery-type behavior of the as-synthesized CMS electroactive materials. At a current density of 5 A g−1 this electrode delivers a significant specific capacity of 667 C g-1 and maintained a considerable proportion of its initial capacity, with a retention value of 83.2 % even after undergoing 3000 charge/discharge cycles. In addition, an asymmetric supercapacitor is fabricated by setting up the synthesized NF/rGO/CMS sample as the positive electrode and activated carbon as the negative electrode. The constructed device not only delivers an impressive energy density of 63.3 Wh kg-1 accompanied by an outstanding power density of 11214.5 W kg−1, but also exhibits a considerable cycling durability, enduring only a 12 % decline in specific capacitance after 3000 charge/discharge cycles at a current density of 5 A g−1.

Influence of the current density on the properties of electrodeposited Ni-W- Ti2AlC composite coatings

In this work, Ni-W-Ti2AlC composite coatings with anti-wear and anti-corrosion abilities were prepared using direct current electrodeposition. The study primarily focuses on the influence of different current densities on the structure and properties of Ni-W-Ti2AlC composite coatings. The microstructural, mechanical properties, and electrochemical performances were studied by using SEM, XRD, EDS, and Tafel polarization techniques. The results indicated that Ti2AlC is successfully co-deposited into the Ni-W coating, and the average grain size of the Ni-W-Ti2AlC composite coating is 15.2 nm. The significant improvement in hardness, wear resistance, and corrosion resistance of Ni-W-Ti2AlC composite coating is attributed to the effects of solid solution strengthening and the uniform distribution of the microstructure. The suitable current density has a great influence on the properties. The microhardness of Ni-W-Ti2AlC composite coatings was increased by 99.59% at a current density of 5 A dm−2 compared to 3 A dm−2. At the same time, the friction coefficient decreased by 13.89%.

Pulse electrodeposition of Ni–P alloy coatings from Watts baths: P content, current efficiency, and internal stress

Ni–P alloy has been used as a protective coating for mechanical parts, a surface material for electronic parts, and an electrocatalyst for water electrolysis. Ni–P alloy electrodeposition was performed by adding H3PO3 to Watts baths under four different types of pulse current conditions and compared with direct current (DC) electrodeposition. When the peak current density was kept constant and the off time was extended, the P content increased, and the current efficiency decreased. When the off time was extended while the average current density remained constant, the P content peaked. This is thought to be due to a change in the phosphorus precipitation mechanism from indirect to direct. The internal stress trend of the Ni–P electrodeposition was measured in-situ using a spiral contractometer up to about 20 μm thickness. The results confirmed that it exhibited internal tensile stress due to hydrogen desorption. As the current efficiency decreased, the internal tensile stress tended to decrease because some excess hydrogen was not desorbed and remained inside. The internal tensile stress could be remarkably reduced to half that of DC electrodeposition while maintaining a high current efficiency by reducing the frequency of pulse electrodeposition to accelerate hydrogen desorption, or by applying a reverse current to consume the electrons that induce hydrogen production.

The Effect of the Rare Earth Element Cerium on the Electrocrystallization and Microstructure of Nickel Electrodeposits in Industrial Electrolytes

To meet the industrial production needs for high-quality and precisely controllable structured high-end nickel foils, rare Earth compounds are added as additives in complex industrial electrolytes to improve the quality of the nickel deposition layer. This study investigates the effects of adding rare Earth compounds to the existing industrial production electrolytes (which already contain various organic and inorganic additives in a mixed acid solution) on the surface microstructure, cerium content, grain size, and crystal orientation of the nickel deposition layer. Using direct current electrodeposition, different concentrations of rare Earth compounds were added to the industrial electrolyte, and the cerium content, grain size, and crystal orientation were characterized. The results show that adding 0.8 g·l−1 CeCl3 accelerates the nucleation rate and shortens the nucleation relaxation time. The addition of rare Earth elements promotes multi-directional preferential growth, resulting in uniform and fine grain size, improved grain structure of the deposition layer, and reduced surface roughness of the nickel plating layer. Therefore, rare Earth elements can be used to regulate the structure, microstructure, and grain refinement of the nickel deposition layer without affecting its composition.

Rational design of porous vanadium-based alloys modified with a Ni-Cu-Mo coating for alkaline water electrolysis

The development of a hydrogen evolution catalyst with both catalytic activity and stability is critical for hydrogen production from electrolytic water. Herein, a V-based porous alloy was prepared via high-energy ball milling and solid-state sintering. Then, the V-based porous alloy was modified with a Ni-Cu-Mo ternary alloy coating by direct current electrodeposition to obtain a composite hydrogen evolution cathode with high hydrogen evolution activity. The substrate has a certain hydrogen storage capacity combined with a high-activity Ni-Cu-Mo coating. The composite hydrogen evolution cathode exhibited high electrocatalytic activity toward the HER. It can afford a lower overpotential of 93 mV and a smaller Tafel slope of 97.4 mV/dec with a current density of 10 mA/cm2 in 1.0 M KOH. The composite hydrogen evolution cathode demonstrated outstanding stability after 2000 cycles and good durability after intermittent electrolysis for 20 h. Hydrogen protons can protect the components of the cathode composite from dissolution during discontinuous constant potential electrolysis. The composite hydrogen evolution cathode also exhibited a strong catalytic capacity for hydrogen evolution during intermittent electrolysis under alkaline conditions.

Tenfold Enhancement of Wear Resistance by Electrosynthesis of a Nanostructured Self‐Lubricating Al2O3/Sn(S)MoS2 Composite Film on AlSiCu Casting Alloys

Enhancing tribological performance through nanostructure control is crucial for saving energy and improving wear resistance for diverse applications. We introduce a new electrochemical approach that integrates aluminum (Al) anodization, tin alternating current (AC) electrodeposition, and anodic MoS2 electrosynthesis for fabricating nanostructured Al2O3/Sn(S)MoS2 composite films on AlSiCu casting alloys. Our unique process uses Sn‐modified MoS2 deposition to form robust solid lubricant MoS2–SnS electrodeposits within the nanochannels and microsized voids/defects of anodic alumina matrix films on the base materials, resulting in a bilayered Al2O3/SnSMoS2 and MoS2–SnS–Sn composite film. The AC‐deposited Sn enhances conductivity in the anodic alumina matrix film, acts as catalytic nuclei for Sn@SnS@MoS2 core‐shell nanoparticles and a dense top layer, and serves as a reductant for the direct synthesis of hybrid solid lubricant MoS2–SnS from MoS3 by anodic electrolysis of MoS42− ions. The resulting nanocomposite film provides a two‐fold increase in lubricity (friction coefficient (COF) μ = 0.14 ⇒ 0.07) and a ten‐fold improvement in wear resistance (COF μ < 0.2) compared to conventional Al2O3/MoS2 film formed by anodizing and reanodizing. The effectiveness of the Al2O3/Sn(S)MoS2 composite is further validated through real automotive engine piston tests.

The mechanism of enhanced electrocatalytic water splitting on S-doped NiFe2O4/Ni–Fe alloy@copper foams

The development of bifunctional catalysts with subtle structures, high efficiencies, and good durabilities for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is crucial for overall water splitting. In this work, a multicomponent S-doped NiFe2O4/Ni–Fe micro nano flower electrocatalyst was synthesized rapidly on foam copper using a simple one-step constant current electrodeposition method. The introduction of S leads to the transformation of the microsphere structure of the Ni–Fe alloy into a cauliflower-like morphology and induces changes in the surface electronic structure, significantly enhancing the catalytic performance for the HER and OER. The S-NiFe2O4/Ni–Fe alloy/CF showed low overpotentials of 220 and 66 mV at 10 mA cm−2 in 1.0 M KOH for the OER and HER, respectively. High durability OER and HER performances were demonstrated through 60 h of chronopotentiometry and 6000 CV cycles test. Excellent overall water splitting electrocatalytic activity was observed in the S-NiFe2O4/Ni–Fe alloy/CF‖S-NiFe2O4/Ni–Fe alloy/CF two-electrode system. In particular, active-phase NiOOH, a highly active substance for OER, can be controllably formed in the reaction process owing to the nanoflower structure of multi-layer sulfur which slows down the dissolution of NiFe2O4/Ni–Fe alloy. These results suggest that this composite structure is a promising bifunctional electrocatalyst.