Electrodeposition Bath Research Articles

(Digital Presentation) Pulsed-Waveform Electrodeposition of Fe-W Brazing Interlayers for Fusion Applications

Numerous government and commercial entities are currently engaged in research toward net-energy-positive nuclear fusion electricity generation technology, which if successfully developed would revolutionize the energy economy and have a significant beneficial impact on carbon emissions and anthropogenic climate change. One fusion subsystem with significant remaining engineering challenges comprises the multitude of divertor modules installed on the plasma-facing surface of modern nuclear fusion reactors. These divertors must absorb/conduct steady-state heat fluxes on the order of 10–20 MW/m2 in an extremely harsh environment, including high-energy neutron bombardment. One common material choice for the plasma-facing portion of these components is tungsten, which provides a high melting point, high sputtering resistance, low tritium retention, and other benefits. As the thermal conductivity of tungsten is somewhat low, however, these tungsten components are often paired with a heat sink made from a more thermally-conductive material, such as copper-chromium-zirconium alloy, CuCrZr. While these materials can be joined by a number of methods, such as diffusion bonding and brazing, the dramatic mismatch in coefficient of thermal expansion (CTE; ~4 μm/m/K and ~17 μm/m/K for tungsten and CuCrZr, respectively) has a significant detrimental effect on the joint strength under these high-temperature, high-heat flux conditions. Development of a means for mitigating this CTE mismatch is imperative for the use of these materials to be feasible in a practical fusion device.This talk will present results to date on development of an electrodeposited functionally-graded iron-tungsten (Fe-W) interlayer system for mitigation of the CTE mismatch between tungsten and CuCrZr in brazed joints. In theory, an interlayer with a CTE functionally graded between “tungsten-like” and “copper-like” values should significantly mitigate the thermally-induced stresses at the tungsten/CuCrZr joint. A key objective of the work is to demonstrate sufficient control over the local interlayer composition, residual stress, and other properties by adjusting primarily the pulse/pulse-reverse electrical waveform parameters, so as to allow interlayer preparation from a single electrodeposition bath. Results from electrodeposition trials and mechanical testing of brazed joints under ambient conditions as an initial screen for interlayer performance will be discussed, in anticipation of high-heat flux testing of joint performance under fusion-relevant conditions, where the ultimate goal is demonstration of increased tungsten/CuCrZr joint lifetime under thermal load via inclusion of graded interlayers, as compared to similar joints without interlayers. Figure Caption (Left) Tungsten substrate with electrodeposited Fe/W interlayer. (Right) Brazed tungsten/CuCrZr sample with Fe/W interlayer. Figure 1

Minimum Thickness of Continuous Cu Layers on Mo from Fluoride Free Electrolytes

Mo as a refractory metal has physical properties which are of interest for applications in CIGS photovoltaic cells fabrication and for next generation of liners for Cu interconnects[1]. Therefore it is of fundamental and practical interest to develop a process for Cu metallization of Mo surfaces where contiguity and high coverage is achieved at minimum thickness. However, one of the obstacles that prevent readily use of Mo as substrate for Cu electrodeposition is tendency of its surface to form a high quality oxide[2] ,[3].The surface energy of Mo-oxide is much lower than Cu which results in sporadic 3D nucleation and low adhesion of Cu deposit[2]. The presented work addresses this fundamental problem by combining the knowledge/breakthroughs demonstrated in the field of electro-polishing of refractory metals such as Nb[4] with common pulse electrodeposition practice[1] ,[5]. A design of deposition pulse reverse potential/current function for Cu is presented which converts a Mo-oxide/Cu to a Mo/Cu interface. Elaborate measurements of the thin film impedance during the Cu growth complemented with Pb UPD decoration studies and AFM surface morphology analysis are presented. These data indicate that Cu layers reach full contiguity and coverage of the Mo substrate at the thickness level of 3-5 nm. Considering that common Cu electrodeposition bath chemistry for interconnects contains additives whose incorporation makes Cu deposit somewhat incompatible with photovoltaic layers[1], this work presents the Cu solution chemistry which is additive free and can serve as a base for further improvement of the specific Cu deposition processes depending on its application.[1] . J. Bi et al, Journal of Power Sources, 326, (2011) 211.[2] . D. Mercier et al, Journal of the Electrochemical Society, 160 (2013) 3103.[3] . M. Pourbaix, Atlas of electrochemical equilibria in aqueous solutions. 2d English ed. 1974, Houston, Tex.: National Association of Corrosion Engineers.[4] . Journal of The Electrochemical Society, 160 (9) E94-E98 (2013).[5] . J.C. Puippe and F. Leaman, Theory and Practice of Pulse Plating, AESF, (1986).

Effect of pulse reverse current waveform on tribological and mechanical properties of electrodeposited nickel–tungsten alloys on brass substrate

ABSTRACT The precise control of tungsten content of electrodeposited nickel–tungsten (NiW) on brass substrate was achieved by applying a well-designed pulse reverse current waveform. A crack-free, uniform and, mirror-like finish surface was obtained by using a novel derivative of propargyl compound, propargyl-oxo-propane-2,3-dihydroxy, as a brightener and grain refiner into the electrodeposition bath. This study indicates that the electrodeposited nickel–tungsten alloys with an optimum tungsten content (32 wt%) possesses outstanding mechanical and, wear performance, also with very low friction of coefficient of 0.2.

Increasing the structural and compositional diversity of ion-track templated 1D nanostructures through multistep etching, plastic deformation, and deposition

Ion-track etching represents a highly versatile way of introducing artificial pores with diameters down into the nm-regime into polymers, which offers considerable synthetic flexibility in template-assisted nanofabrication schemes. While the mechanistic foundations of ion-track technology are well understood, its potential for creating structurally and compositionally complex nano-architectures is far from being fully tapped. In this study, we showcase different strategies to expand the synthetic repertoire of ion-track membrane templating by creating several new 1D nanostructures, namely metal nanotubes of elliptical cross-section, funnel-shaped nanotubes optionally overcoated with titania or nickel nanospike layers, and concentrical as well as stacked metal nanotube-nanowire heterostructures. These nano-architectures are obtained solely by applying different wet-chemical deposition methods (electroless plating, electrodeposition, and chemical bath deposition) to ion-track etched polycarbonate templates, whose pore geometry is modified through plastic deformation, consecutive etching steps under differing conditions, and etching steps intermitted by spatially confined deposition, providing new motifs for nanoscale replication.

Butynediol’s Role beyond Brightening Additive during Electrodeposition of Cobalt

Butynediol (2-Butyne-1,4-diol), a well-known type-II brightening additive, changes the interfacial pH resulting in the formation of porous cobalt hydroxide film of ca. 1 μm thickness over the copper substrate in a short duration of electrodeposition (2 min) and at a very low current density (−5 mA cm−2) from sulfate bath. In the absence of butynediol, a metallic cobalt layer was observed under identical deposition conditions. The choice of anions (sulfates, chlorides and nitrates) in the electrodeposition bath determines the kind of electrodeposited films obtained, viz., cobalt, cobalt/cobalt hydroxide, and compact cobalt hydroxide. The adsorption of butynediol enhances hydrogen evolution due to water reduction that facilitates the formation of porous microstructures of cobalt hydroxide. Competition for adsorption sites between butynediol and chloride and dissolution of cobalt hydroxide by diffusing protons result in a mixed metallic cobalt particle and porous cobalt hydroxide microstructure. The variations in the phases and microstructures of electrodeposits were evidenced through the difference in the magnetic and electrocatalytic properties.

Study of Glycerol as an Additive in Ni-Mo Electrodeposition

This paper evaluates the effect of adding glycerol to the electrodeposition bath on the deposition efficiency and characteristics of Ni-Mo coating in concentrations ranging from 0.07 to 0.82 mol.L-1. Evaluation of the corrosion resistance was performed by means of weight loss tests in four different periods of immersion. Electrochemical techniques, such as obtaining polarization curves, linear polarization resistance, corrosion current density, corrosion potential, and electrochemical impedance spectroscopy were applied. Corrosion measurements were obtained in 0.5 mol.L-1 NaCl acid solution and 0.5 mol.L-1 NaOH alkaline solution. The morphology and microstructures of electrodeposited were analyzed using Scanning Electron Microscopy and Spectrometry X-Ray Diffraction. The effect of glycerol on Ni-Mo hardness was evaluated by Vickers microhardness measurements. The presence of glycerol in the electrodeposition bath increased the grain size and decreased the hardness of the coating. However, it promoted the formation of a more compact and less porous coating, increasing the corrosion resistance of the coating. Moreover, the addition of 0.82 mol.L-1 glycerol increases current efficiency, thereby reducing the amount of energy consumed during electroplating.

In-site pulse electrodeposition of manganese dioxide/reduced graphene oxide nanocomposite for high-energy supercapacitors

Manganese dioxide/reduced graphene oxide (MnO2/RGO) nanocomposite material was synthesized by the in-situ anodic pulse electrodeposition method to fabricate symmetric supercapacitors. The effects of the pH value of the electrodeposition bath were considered on the properties of fabricated electrodes. Three pH values ​​of 4, 7, and 10 were evaluated, and physicochemical properties were studied using field-emission scanning and transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, nitrogen gas sorption isotherm, and thermogravimetric analysis. The electrochemical evaluation was performed by galvanostatic charge/discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy techniques. The results revealed that the MnO2/RGO nanocomposite prepared at pH = 7 (i.e., MGO7) exhibited a maximum specific capacitance of 693.4 F g−1 at a current density of 0.5 A g−1. The symmetric supercapacitor based on MGO7 was also assessed using GCD and CV tests. Its specific capacitances at current densities of 0.5 and 20 A g−1 were 577.9 and 290.0 F g−1, respectively. The symmetric supercapacitor maintained 79.2% of initial capacitance after 5000 consecutive charge/discharge cycles at a current density of 4 A g−1. The highest energy density of 80.3 Wh kg−1 at the power density of 0.625 kW kg−1 and the highest power density of 25 kW kg−1 at the energy density of 40.3 Wh kg−1 was achieved by the fabricated supercapacitor.

Study on electrodeposited CuFe film on Cu electrode as an efficient catalyst for electrochemical reduction of nitrate

In this research, a novel CuFe catalyst was fabricated using a simple, single-step electrodeposition method on a traditional Cu electrode. CuFe films from various electrodeposition baths with different Cu and Fe ratios were prepared by chronopotentiometry and characterised by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray analysis (EDX), and Pb underpotential deposition (Pb-UPD). The Cu electrode coated with CuFe8020 (from electrodeposition bath containing 80% Cu and 20% Fe) showed the highest reduction current among the film produced. The Cu electrode coated with CuFe8020 exhibited three times higher nitrate reduction efficiency and less undesired products like NO2− và NH4+ than the traditional Cu.

CoMo heterohierarchical foam-structured cathode for anion exchange membrane water electrolyzer

It is important to consider the synergy of heterostructures to improve the slow kinetics of water dissociation in the alkaline hydrogen evolution reaction (HER). Herein, we report a simple method to design a heterohierarchical CoMo catalyst. The CoMo catalyst was prepared by simple one-pot electrodeposition on carbon paper (CP). The CoMo/CP catalyst was optimized for the alkaline HER by controlling the electrodeposition bath conditions, potential, and time. The optimized catalyst shows the heterohierarchical structure containing the electrically conductive metallic Co in the bulk and Mo-incorporated Co containing Mo4+ at the surface. It exhibited a lower HER overpotential of 0.11 V at −20 mA/cm2 compared to those of the others owing to the synergetic effect of the between the Co and Mo incorporated Co. The results highlight the advantages of the simple method developed herein for the design of heterohierarchical catalysts.

Low-temperature Sn electrodeposition: Texture evolution, grain boundary constitution and corrosion behavior

Electrodeposition of Sn was conducted at three different electrolyte bath temperatures: 25 °C, 20 °C, and 15 °C in galvanostatic conditions. Corrosion analysis using the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization revealed that decreasing the electrodeposition bath temperature reduced the corrosion resistance of Sn coatings. The 25 °C coating exhibited the highest polarization resistance (Rp) value of 71,460 Ω.cm2 and lowest corrosion current density (icorr) value of 0.251 μA.cm−2, whereas the 15 °C coating exhibited Rp value of 16,120 Ω.cm2 and icorr value of 0.891 μA.cm−2. The electrochemical response was correlated with the texture and grain boundary constitution using the electron backscatter diffraction (EBSD) technique. It was observed that decreasing the electrodeposition temperature decreased the predominance of the (100) texture, increased the strain, and reduced the average grain size of Sn grains. The Sn coating with the lowest corrosion resistance displayed a predominant (501) texture, lowest grain size, and highest strain within the Sn grains.

Zinc Electrodeposition in Acetate‐based Water‐in‐Salt Electrolyte: Experimental and Theoretical Studies

AbstractZinc electroplating has found applications in many fields. The chemical composition of the electrodeposition bath can have a great impact on the final coating quality and the economics of the process. In traditional aqueous electrolytes, zinc deposition competes with the hydrogen evolution and oxygen reduction reactions, which can lead to hydrogen embrittlement of the substrate as well as decrease in efficiency. Highly concentrated water‐in‐salt electrolytes can suppress these reactions significantly. Here, we show that electrodeposition of zinc with high efficiencies can be achieved using an acetate‐based water‐in‐salt electrolyte at room temperature. Nucleation studies confirm that at potentials more negative than −1.30 V vs. Ag/AgCl, the three‐dimensional (3D) nucleation process becomes instantaneous, while at more positive potentials it is progressive. Using two of the most common nucleation and growth models, Scharifker‐Mostany and Mirkin‐Nilov‐Heerman‐Tarallo, nucleation parameters such as the nucleation rate constant and nuclei density are found, showing a good agreement between the two models.

Photoelectrochemical solar cell study of electrochemically synthesized Cd1-xZnxTe thin films

Cd1-xZnxTe thin films of different zinc concentrations were prepared using simple and cost effective electrodeposition technique. The films were coated on FTO substrates using a chemical bath consisting of CdSO4, ZnSO4 and TeO2. In this deposition of Cd1-xZnxTe thin films electrodeposition potential, bath temperature, precursor concentrations and pH were optimized. The morphological, structural and optical characterizations of the films deposited with various zinc compositions are also reported. The grown films displayed a high-quality polycrystalline films with crystallites orientation along (111) direction. The deposited Cd1-xZnxTe alloy films showed direct band gaps varying between 1.67 and 2.15 eV depending upon zinc concentration. Photo electrochemical (PEC) solar cells fabricated using the grown alloy films of different zinc concentration showed increased efficiency for the increase of zinc concentration.

Comparative Study of Sheet Resistance Stability of Electro-Deposited Ni/Co - Alloy Thin Films

Cu is conventionally used for interconnect material in most of high performance and high integration of logic devices because Cu has low conductivity as 1.7×10－8 Ω･m and also has excellent electromigration resistance. However, Cu requires a barrier layer for eliminating Cu diffusion into SiO2 or Si. Because of the limitation of the barrier layer thickness, the effective resistance of the wiring including the barrier layer greatly increases with decreasing of the width of Cu wiring less than 10 nm. Therefore, many researches have been reported about the development of barrier layer-free wiring technology using Co or Ru with low resistivity compared to Cu wiring system. Ni has similar physical properties e.g. resistivity, thermal expansion coefficient, diffusion coefficient, etc. like Co or Ru, however, few research on electrical properties has been done so far. In this study, Ni, Ni-Co alloys, and Co are deposited by electrodeposition and crystallographic structure and electrical properties were evaluated.A Ni or W (5 nm) seed layer were deposited onto thermally grown SiO2/Si(001) substrates (10 mm sq.) at R.T. by RF sputtering. After forming the seed layer, Ni or Ni-Co alloy or Co thin film (50 nm) was deposited. Table 1 shows the composition of electrodeposition bath. After the deposition, all samples were annealed in argon atmosphere (0.1 Torr) at 450°C for 30 minutes. Elemental analysis was done by Energy Dispersive X-ray spectrometry (EDX). The crystal structure, Chemical bonding state and electrical properties were evaluated by X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and 2-terminal Method, respectively, before and after annealing.Figure 1 shows the sheet resistance change of Ni, Ni-Co alloy, or Co films before and after 450°C - 30 minutes annealing using (a) Ni and (b) W as a seed layer. There was no significant difference in sheet resistance between the Ni or W seed layer samples. In the case of Ni or Ni-Co alloy films, the sheet resistance after annealing was very stable for both seed layers, Ni and W. On the other hand, the sheet resistance of Co films increased and they were considered to be oxidized by XPS and XRD results. Co film by electrodeposition was oxidized but Ni and Ni-Co alloy films were not oxidized by annealing, so they are better wiring metal than Co in terms of oxidation resistance. Figure 1

Effect of Mechanical Agitation on Cr-Al<sub>2</sub>O<sub>3</sub> Nanocomposite Coatings Fabricated from Trivalent Chromium Electrodeposition

In the present work, Cr-Al2O3 nanocomposite coatings were electrodeposited onto a copper substrate using a modified trivalent chromium electroplating bath with the addition of 80nm Al2O3 powder. The effects of mechanical agitation of electrodeposition bath on Al2O3 particles dispersion and particles embedment were studied. The Cr-Al2O3 nanocomposite samples were subjected to different tests to characterize their surface morphology, crystalline structure, and mechanical properties. The crystalline structure, composition and surface morphology of the deposits were studied by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscopy (FESEM). The corrosion resistance test was carried out by electrochemical polarization method. The microhardness was studied via Vickers Microhardness Test. The variation in the microhardness as a main property to achieve enhancement of Al2O3 incorporations with Cr matrix. From the EDX analysis, Cr-Al2O3 nanocomposite deposited at 200 rpm stirring speed showed the highest weight percentage (wt%) of alumina. The hardness results showed the Cr-Al2O3 composite coating has the best performance at 200 rpm stirring speed which the hardness increased 32.3 % compared to that of Cr coating. The corrosion current density (icorr) of Cr-Al2O3 coating achieved highest value at 200 rpm. This result revealed that the corrosion resistance of Cr-Al2O3 coating decreases with increasing Al2O3 particles content.

Optimization and characterization of pulse electrodeposited nickel selenide nanostructure as a bifunctional electrocatalyst by response surface methodology

The electrocatalytic activity of the pulse electrodeposited Ni–Se coating on nickel foam (NF) for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) was optimized by design of experiments. In this study as the first step of optimization, the condition of electrodeposition bath containing the ratio of Se/Ni, pH, and temperature was optimized. The response surface methodology (RSM) in central composite design (CCD) was used for experiments based on the parameters of the ratio of Se/Ni and pH. The prediction model after carrying out the analyses of variance (ANOVA) on the responses showed the best desirable values for the ratio of Se/Ni and pH were 0.7 and 3.6. The nanostructure Ni–Se electrode electrodeposited in the optimal condition requires 103 and 249 mV (vs. RHE) for delivering 10 mA/cm2 in HER and OER, respectively. To temperature survey, the optimized Ni–Se electrode was synthesized at 25, 40, and 60 °C. Results showed that the electrode electrodeposited at the ambient temperature with large electrochemically active surface area of 8960 and low Tafel slopes of 86 and 35 mV/dec has the superior electrocatalytic performance for HER and OER, respectively.

Impact of ionic liquid [FPIM]Br on the electrodeposition of Ni and Co from an aqueous sulfate bath

A novel ionic liquid, namely, 1-(4-fluorobenzyl)-3-(4-phenoxybutyl)imidazole-3-ium bromide [FPIM]Br, was used as an additive for cobalt (Co) and nickel (Ni) electrodeposition from acidic sulfate and Watts baths, respectively. The effect of [FPIM]Br on the electrodeposition mechanism of the coatings was investigated by a variety of electrochemical methods (potentiodynamic cathodic polarization, cyclic voltammetry, and anodic linear stripping voltammetry) as well as by morphologic techniques (XRD, SEM, EDX and AFM). The inhibition of Co2+ and Ni2+ ions deposition in the presence of [FPIM]Br was found to lead to finer-grained deposits. Adsorption of [FPIM]+ on the copper substrate is shown, and the process obeys the Langmuir adsorption isotherm. The cathodic current efficiency (CCE%), hardness and corrosion resistance for Co2+ and Ni2+ deposition in the electrodeposition bath were found to increase when additive was included. The resultant surface morphologies demonstrated that the [FPIM]Br additive served as an effective brightener that can produce highly uniform and smooth Co and Ni deposits.

Effects of Additives in an Electrodeposition Bath on the Surface Morphologic Evolution of Electrodeposited Copper

Effects of Additives in an Electrodeposition Bath on the Surface Morphologic Evolution of Electrodeposited Copper

Preparation of Nanoparticle Porous-Structured BiVO4 Photoanodes by a New Two-Step Electrochemical Deposition Method for Water Splitting

In the synthesis method of a BiVO4 photoanode via BiOI flakes, a BiOI film is formed by electrochemical deposition in Step 1, and a vanadium (V) source solution is placed by drop-casting on the BiOI film in Step 2. Following this, BiVO4 particles are converted from the BiOI–(V species) precursors by annealing. However, it is challenging to evenly distribute vanadium species among the BiOI flakes. As a result, the conversion reaction to form BiVO4 does not proceed simultaneously and uniformly. To address this limitation, in Step 2, we developed a new electrochemical deposition method that allowed the even distribution of V2O5 among Bi–O–I flakes to enhance the conversion reaction uniformly. Furthermore, when lactic acid was added to the electrodeposition bath solution, BiVO4 crystals with an increased (040) peak intensity of the X-ray diffractometer (XRD) pattern were obtained. The photocurrent of the BiVO4 photoanode was 2.2 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE) under solar simulated light of 100 mW/cm2 illumination. The Faradaic efficiency of oxygen evolution was close to 100%. In addition, overall water splitting was performed using a Ru/SrTiO3:Rh–BiVO4 photocatalyst sheet prepared by the BiVO4 synthesis method. The corresponding hydrogen and oxygen were produced in a 2:1 stoichiometric ratio under visible light irradiation.

Zn composite corrosion resistance coatings: What works and what does not work?

Corrosion is one of the most significant contributors to structural degradation in process industries. It causes process equipment failure, which can led to severe safety issues. One approach to address this concern is to provide a preventive barrier-coating to equipment. Due to its superior reductive property, zinc is usually employed as a sacrificial anode in conventional corrosion-resistance methods. Nickel is also used to both mechanically strengthen the barrier and improve overall corrosion resistance; therefore, zinc, zinc-nickel alloys, and zinc-nickel-oxide composite coatings are commonly employed for anti-corrosion purposes. The complexation of zinc and nickel ions by agents (citrate, acetate and EDTA) can stabilize the electrodeposition bath and extend the pH of Ni(OH)2 and ZnO precipitation to improve corrosion resistance in the resultant coating. This paper reviews the challenge with these type of coatings and presents progress in Zn and Zn-Ni composite corrosion resistance coatings co-deposited with Al2O3, TiO2, ZrO2, SiO2, and Fe2O3 as means of corrosion control to reduce the probability of process equipment failure due to corrosion, which will improve the overall safety and reliability of processing equipment.

2D alignment of zinc oxide@ZIF8 nanocrystals for photoelectrochemical water splitting

Thin films of zinc oxide nano-sheets loaded with Zeolitic Imidazole Framework 8 nanocrystals were synthesized using electrodeposition and chemical bath deposition for photoelectrochemical application.