Citrate Bath Research Articles

The influence of temperature and the magnetic field on Ni electrodeposition from citrate bath and its electrocatalytic performance towards hydrogen evolution reaction

The demand for energy surpasses the available supply, leading to various economic, social, and environmental consequences. Hydrogen is one of the most clean and renewable source for energy. Therefore, the electrocatalytic hydrogen evolution reaction (HER) presents a promising eco-friendly approach for generating sustainable hydrogen energy. However, in alkaline conditions, HER encounters slow kinetics due to challenges associated with hydrogen adsorption and hydrolysis. In this article, thin Ni films were synthesized using the electrodeposition technique from citrate electrolyte. Their suitability as electrocatalysts for the hydrogen evolution reaction (HER) in a 1 M NaOH solution was estimated. This research investigates how the uniform magnetic field and temperature affect the process of nickel electrodeposition from a citrate bath and its subsequent influence on surface morphology and catalytic properties for the hydrogen evolution reaction (HER). Additionally, alterations in surface material wettability were examined based on changing the temperature during using the magnetic field for the electrodeposition process and shows how this effect on the catalytic performance towards HER. The outputs show that using the magnetic field for fabrication of Ni thin films at room temperature enhances the surface morphology and its catalytic performance for HER. However, the study reveals that using the temperature for Ni electrodeposition improves its catalytic performance independently of the magnetic field, whereas combining temperature with the magnetic field for Ni thin film fabrication diminishes their catalytic performance for the hydrogen evolution reaction (HER). The nickel thin film produced at 25 °C under the influence of a magnetic field, whether parallel or perpendicular, demonstrates the lowest overpotential of − 268 mV to achieve a current density of 10 mA cm−2. Additionally, it exhibits the smallest Tafel slope values of 106 mV dec−1 and 128 mV dec−1 for the parallel (Bǁ) and perpendicular (BꞱ) directions, respectively. However, the magnetic field effect diminishes at elevated temperatures. Nickel thin films prepared at 35 °C under the influence of perpendicular (BꞱ) and parallel (Bǁ) directions exhibit higher overpotential values of − 314 mV and − 322 mV, respectively.

Strategic Development of Ni–Cu–Fe2O3 Composite Coatings to Strengthen Mild Steel Against Corrosion

Mild steel is extensively employed in various industries due to its affordability and versatility. However, its susceptibility to corrosion poses a significant challenge. This study explores the efficacy of protecting mild steel by applying coatings composed of highly noble copper and its alloys. In this direction, Ni–Cu alloy and Ni–Cu–Fe2O3 coating have been developed from a sulfate citrate bath on mild steel through the electrodeposition method. The alloy and composite coating deposition was done at different current densities 1 A dm−2, 2 A dm−2, 3 A dm−2, and 4 A dm−2. The copper content of the coating has increased with an increase in current density in both alloy and composite coatings. The deposit with a high Copper content showed lower crystallite size with a lower corrosion rate value at a current density of 3 A dm−2. The trace addition of Fe2O3 into the Ni–Cu alloy matrix has improved the overall corrosion resistance of the mild steel materials as compared to bare Ni–Cu alloy coating.

Effect of Cetyl Trimethyl ammonium bromide (CTAB) amount on the Nanoindentation creep behaviour of Sn-cu-Y2O3 nanocomposite Lead-free solder

Sn-Cu-Y2O3 nanocomposite solder is synthesized from a citrate bath by pulse electrodeposition route. Y2O3 powder is synthesized from a sol-gel assisted combustion route. Different techniques such as SEM, XRD, and TEM are used to characterize Y2O3 powder. The particle size of Y2O3 powder is found to be 27 nm. The effect of adding cetyl trimethyl ammonium bromide (CTAB) on the synthesis of Sn-Cu-Y2O3 nanocomposite lead-free solder is studied. The amount of CTAB is varied for a particular amount of Y2O3 powder. It is carried out to find the exact ratio of CTAB for better dispersion of Y2O3 powder in the electrolytic bath. Because the distribution of reinforcement in the matrix which is associated with the dispersion of Y2O3 powder in the electrolyte is as important as the amount of reinforcement in the solder matrix. For the synthesis of nanocomposite solder, the optimum ratio of CTAB to Y2O3 is found to be 1:1. After the synthesis of nanocomposite solder, the influence of Y2O3 powder on the melting temperature of the solder is also studied. Incorporating Y2O3 has little effect on the melting point of the nanocomposite solder. Nanoindentation creep test results showed that the deposit at 0.2 A/cm2 (monolithic solder) has a lower creep resistance than the nanocomposite solders. Additionally, the creep resistance of the nanocomposite with a CTAB to Y2O3 ratio of 1:1 was higher.

Effect of Cathode Surface Area on the Electrodeposition Rate, Composition, and Microhardness of Co–W Coatings Deposited from a Citrate Bath

Effect of Cathode Surface Area on the Electrodeposition Rate, Composition, and Microhardness of Co–W Coatings Deposited from a Citrate Bath

Electrodeposition mechanism of Cu2CoSnS4 thin films onto FTO-coated glass: Effect of some additives

In this study, we synthesized thin films of semiconductor Cu2CoSnS4 (CCTS). We investigated the mechanism of CCTS electrodeposition precursor onto fluorine-doped tin oxide (FTO) surface. This investigation utilized various mixed additives (Trisodium citrate, Glycine, and Boric acid) through voltammetric and chronoamperometric techniques. The polarization cathodic indicated that the additives narrowing the potential range for electrodeposition of the four elements. The reduction of S2O32− was mainly induced by the effect of metal ions. The current transient was analyzed using the Astley and Scharifker-Hills models. Trisodium citrate electrolyte showed an instantaneous model followed by 3D diffusion-limited growth. Both trisodium citrate mixed with glycine and trisodium citrate mixed with boric acid shifted towards the progressive nucleation model. Trisodium citrate with tartaric acid showed a strong agreement with progressive nucleation. In-situ electrochemical impedance spectroscopy (EIS) evaluated a low charge transfer resistance for CCTS precursor electrodeposition in trisodium citrate electrolyte. The X-ray diffraction and Raman analysis study revealed the stannite structure of the obtained Cu2CoSnS4 thin film. The morphological properties and thickness of the films were investigated using a scanning electron microscope (SEM). The compositions were determined using energy dispersive spectroscopy which indicated different atomic ratios of Cu-Co-Sn-S. The maximum absorption was observed within the 1.5 eV range for the film deposited in the Trisodium citrate bath, as determined by spectroscopic ellipsometry.

Preparation of Ni–Mo/GO composite coatings with strengthened mechanical properties and enhanced corrosion resistance

Ni–Mo/GO coatings in thickness of 1.5–3 μm were electrodeposited from a citrate bath containing nickel sulfate, sodium molybdate, GO and SDS. The impacts of GO nanosheets on the surface morphology, structure, mechanical properties and corrosion resistance of the Ni-Mo matrix were explored. Ni-Mo alloy shows an amorphous phase with a smooth and compact surface. The codeposited graphene oxide can refine Ni-Mo microstructure, but also can lead to rougher surfaces with defects. Coefficient of friction (COF) of Ni-Mo matrix decreased, and wear resistance and hardness increased in the presence of GO. The corrosion resistance of Ni–Mo/GO would be improved only if GO concentration exceeded 0.2 g L−1. The preferred concentration of GO was 0.2–0.3 g L−1, which showed satisfactory anti-corrosion performance. The corrosion resistance depends not only the amount of GO present but also its dispersed arrangement and distribution. A higher content of GO, a dispersion of particles parallel to the substrate and uniform GO distribution in the metallic matrix can hinder the diffusion of corrosive species, leading to an improved corrosion resistance.

Electrochemical deposition and characterisation of NiTi alloy coatings for better corrosion protection

ABSTRACT The present study reports the electrochemical deposition and characterisation of Nickel-Titanium (NiTi) alloy coatings on mild steel (MS) from citrate bath having nickel sulphate and titanium oxysulphate as salts, tri-sodium citrate as complexing agent and glycerol as the brightener. Bath composition and operating variables were optimised by the conventional Hull cell method for bright and uniform coating. NiTi alloy coatings were developed at varied current densities (1.0 A/dm2 to 4.0 A/dm2), keeping pH = 4.0. The corrosion behaviours of NiTi alloy coatings were evaluated by electrochemical AC and DC methods in a 3.5 per cent sodium chloride solution. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) techniques were used to study the phase structure, surface morphology and chemical composition of the coatings, respectively. The observed facts stand to the reason that the bath follows induced type co-deposition in the range of current density studied. Corrosion studies validated that NiTi alloy coating deposited at 4.0 A/dm2 is the most corrosion-resistant among all other current densities. This highest corrosion stability of NiTi alloy, corresponding to 4.0 A/dm2 is attributed to high wt.% of Ti (i.e. 3.5%). The decrease in corrosion rate towards high current density was analysed and discussed.

Pseudo lamellae of Cu6Sn5 on the crystal facet of Sn in electrodeposited eutectic Sn-Cu lead-free solder

Eutectic Sn-Cu lead-free solder is developed using the pulse electrodeposition method from a citrate bath at different current densities like 0.1, 0.2, 0.4, and 0.5 A/cm2. The exact composition of all the deposits was confirmed through atomic absorption spectroscopy (AAS) analysis. The coating deposited at 0.2 A/cm2 constitutes 0.7 wt% of Cu which is similar to the eutectic Sn-Cu composition. Microstructural characterization was carried out with the help of a scanning electron microscope (SEM). Sn was the major constituent in all the deposits while a little amount of intermetallic i.e. Cu6Sn5 was present for the deposits at 0.1 and 0.2 A/ cm2. The energy dispersive spectroscopy (EDS) results showed traces of Cu6Sn5 in the deposits. The formation of Cu6Sn5 was also confirmed through X-ray diffraction (XRD). For the deposit at 0.2 A/cm2, the endothermic peak temperature in DSC is exactly the same as that of the melting point of Sn-Cu eutectic. This electrodeposited microstructure resembles the conventional eutectic Sn-Cu cast structure. The top view of the deposited Cu6Sn5 on the steps of Sn creates an illusion of lamellar structure. The effect of current density on the roughness was analyzed through AFM.

Effect of Surface Area on Electrodeposition Rate, Composition and Microhardness of Co-W Coatings Deposited From a Citrate Bath

Using the example of electrodeposition of Co-W coatings from a citrate bath, it has been experimentally proved that with a large-scale transfer of the results of studying the process rate, composition and properties (microhardness) of coatings under galvanostatic conditions, it is necessary to change the volume of the bath in proportion to the change in surface area. In this case, the current load on the electrolyte is preserved, which is quantitatively determined by the value of the volume current density.

Electrodeposition of Fe-Ni Alloy Films having Invar Compositions with Fe3+ as the Sole Iron Source

Fe-Ni alloy films with invar alloy compositions were electrodeposited from a stable citrate bath containing trivalent iron ions (Fe3+) as the sole iron source. This bath was prepared based on determining the equilibrium constants for acid dissociation, complex formation and precipitation reactions. Electrodeposition was conducted under galvanostatic conditions at 25 °C without agitation and an investigation was carried out into the effects of pH and current density on the composition and microstructure of the films. The results showed that ferric hydroxide (Fe(OH)3), which is normally poorly soluble, did not precipitate after electrodeposition. Fe-Ni alloy films containing 31‒42 mass% Ni (including Fe-36 mass% Ni) were formed with a current efficiency of approximately 70%. The films were smooth and were made up of grains with sub-micron sizes, although some cracks were observed. Fe and Ni were distributed homogeneously throughout the films and the Fe-Ni solid solutions exhibited both face-centered cubic and body-centered cubic structures.

Electrochemical preparation and alkaline water splitting activity of ternary Co–Fe–Mo non-crystalline coatings

The influence of Na2MoO4 concentration on the electrochemical deposition of Co–Fe and Co–Fe–Mo alloy coatings from slightly acidic citrate baths and their electrocatalytic performance for alkaline water electrolysis in 1 M NaOH solution have been examined. The chemical composition and the evolution of the crystallographic structure have been analyzed by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), and scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) measurements. Increasing concentration of Mo in the alloy led to gradual amorphization of the crystalline structure. Electrochemical studies revealed that the cathodic Tafel slope reduced to 69 mV/dec for Co–Fe–Mo alloys. Furthermore, a low overpotential value of −121 mV was observed from polarization studies, which confirmed a good catalytic activity for the alkaline water splitting process.

Size Effect in the Rate of Electrodeposition of Co–W Coatings from a Citrate Bath

Size Effect in the Rate of Electrodeposition of Co–W Coatings from a Citrate Bath

Anodic Dissolution of Surface Layers as a Method of Increasing the Microhardness of Coatings by Alloys of the Iron Group Metals with Tungsten Obtained by Induced Co-Deposition

It is shown that the macroscopic dimensional effect of the composition and properties (microhardness and corrosion resistance) of coatings obtained by induced co-deposition of the iron group metals with tungsten (the effect of the surface area of electrodeposition on the composition and properties) due to the presence of oxide-hydroxide layers in the surface layer, as well as hydrogenation, is a special case of effects of this kind; this, in turn, requires a constant volumetric current density (mA/L) during electrodeposition. It has been established, using examples of electrodeposition of Fe-W and Co-W alloys from a citrate bath, that a change in the volumetric current density at a fixed electrodeposition current density leads to a change in the potential, the current output, and in the composition of the alloy in the coating. Anodic dissolution of the modified surface layer increases the microhardness, but does not eliminate the effect of dependence of the composition and properties of coatings on the electrodeposition surface area.

Influence of Annealing on the Microstructure and Mechanical Properties of Ni-W/Boron Composite Coatings

Ni-W/boron composite coatings are deposited from an ammonia citrate bath with a boron particle suspension. The effect of the boron incorporation into the Ni-W alloy coating and subsequent heat treatment of the deposits on the microstructure and properties of the Ni-W/boron coatings have been investigated. The boron particles can be uniformly dispersed in the Ni-W alloy, which can lead to an enhancement in the wear performance and hardness of the coatings. The XRD results show that a new Ni4W phase can be formed, especially at heat treatment temperatures beyond 400 °C. The grain size of the deposits is smaller than 10 nm with heat treatment temperatures lower than 600 °C and increases with the heat treatment temperature increasing. The higher temperature will significantly cause the grain coarsening (25.8 nm at 700 °C). Furthermore, the hardness and wear resistance increase with the formation of the Ni4W phase and the inverse Hall–Petch relationship at the lower heat treatment temperatures (<600 °C). While the grain coarsening causes the hardness of the deposits to decrease at the temperature of 700 °C.

Hull Cell Investigation of Ni-Mo and Ni-Mo-O Electrodeposits from Ammonium Citrate Baths

Among different Ni-based alloys, Ni-Mo is well-known for the excellent corrosion resistance which makes them a potential alternative for the electroplated chromium. In addition, Ni-Mo alloys have been used as substrates for various purposes and as hydrogen evolution reaction electrocatalyst owing to their good mechanical strength and electrocatalytic activities. Each application requires distinct material properties of Ni-Mo alloys (e.g., composition, morphology, and crystallinity). Therefore, tunability of the material properties of Ni-Mo alloys become important to facilitate them for applications. Synthesis of Ni-Mo alloys has been achieved by various methods (e.g., e-beam evaporation, sputtering, and arc melting); however, high cost and time consumption, especially harsh synthesis conditions, limit the range of studied parameters. Hull cell, an electrodeposition technique, becomes a promising means for the high throughput investigation of synthesis parameters. Similar to other efficient electrodeposition techniques, Hull cell not only provides the tunability of morphology and composition, but also requires a simple setup and near ambient operating conditions. Ni-Mo alloys are electrodeposited via induced co-deposition, implying the dependent reduction of Ni and Mo. Therefore, complexing agent (e.g., citrate ions) is required to control the relative reduction rates of Ni and Mo and consequently tune the material properties via the complexation and the reduction reactions. The complexation between metal precursors and complexing agents generates many different species. Only chemically active species participate in the reduction reactions at the interface of electrolyte and electrode. Thereby, it is necessary to study the distribution of species after complexation to maximize the fraction of chemically active species for Ni-Mo co-deposition. In this work, effects of various synthesis parameters on the formation of Ni-Mo alloys and Ni-Mo-O composites were investigated using Hull cell. Firstly, the fraction of complex species at equilibrium is simulated using material balance with the assistance of MATLAB to understand the complexation of metals and complexing agents as well as predict the solution compositions which maximize the chemically active species for reduction reactions. Also, the effect of various synthesis parameters (e.g., complexing agents (ammonium-to-citrate ratio), Ni/Mo precursor ratio, pH) are experimentally studied and correlated with simulated data to elucidate the deposition mechanism as well as determine the conditions for the transition from Ni-Mo alloys to Ni-Mo-O composites.

Effect of solution pH, precursor ratio, agitation and temperature on Ni-Mo and Ni-Mo-O electrodeposits from ammonium citrate baths.

The induced co-electrodeposition of Ni and Mo is a complex process, where metallic Ni-Mo alloys and Ni-Mo-O composites can originate from the complete and partial reduction of Mo respectively. By adjusting electrolyte compositions and electrodeposition parameters, various metallic, metal/oxide composite, and oxide thin films of Ni-Mo and Ni-Mo-O were electrodeposited from ammonium citrate baths. Ni-ammonia complexes, which play a critical role in promoting the deposition of metallic Ni-Mo alloys, were enhanced at alkaline pH (i.e., 8–10) and lower temperature (i.e., 25–45°C). Moreover, the electrochemical reduction of Ni is under mass transfer limitation, so the deposited Mo content decreased with increasing agitation. On the other hand, higher Mo content can be achieved by relatively higher citrate concentration and larger Mo-to-Ni precursor molar ratio. However, a critical molar ratio of metal precursor resulted in transition from alloy to composite due to Ni inducing the reduction of Mo.

Effects of NH4 +/citrate complexing agent ratio on Ni-Mo and Ni-Mo-O electrodeposits from ammonium citrate baths.

To understand the effect of complexing agents (i.e., ammonium and citrate) in nickel–molybdenum electrodeposition, calculation of the concentration of various Ni and Mo species as a function of pH and initial concentration of metal ions and complexing agents was performed. In addition, linear sweep voltammetry and Hull cell experiments were systematically investigated to understand the effect of current density and ammonium-to-citrate ratio to film compositions, morphology, and crystallinity. The results indicated that Ni(NH3)3 2+ played a critical role in induced co-deposition mechanism of Ni–Mo alloys, which involved the reduced Ni and absorbed H atoms. Microstructure analysis of deposits indicated that the transition from smooth laminarly grown amorphous Ni–Mo–O composites to columnar and nanocrystalline metallic Ni–Mo alloys with a globular structure as the ammonium-to-citrate molar ratio increases. The highest Mo content of alloys was as high as 19 at%, and up to 70 at% O was present in the composites.

Microstructure and corrosion resistance of highly oriented electrodeposited CoNiFe medium-entropy alloy films

The medium-entropy alloy is a newly intriguing material showing superb properties. A simple, one-step method was developed to electrodeposit CoNiFe medium-entropy alloy films from a sulfate and citrate bath. The microstructure and corrosion resistance were investigated in CoNiFe films with varying deposition current densities. It shows the face-centered cubic structure with a <111> preferential orientation. HRTEM-EDS observations further show information on the nanostructure and element distribution. The films exhibit a strong corrosion resistance in 3.5 wt.% NaCl solution. The films electrodeposited with a current density of 44.4 A/dm2 shows a low self-corrosion current density of 4.72 × 10−6 A⋅cm−2 in 3.5 wt.% NaCl solution. The corrosion mechanism was proposed in combination with electrochemical impedance spectroscopy results. The outstanding properties were attributed to the near-equimolar ternary components. The results lay a solid foundation for developing of highly oriented medium-entropy alloy films with strong corrosion resistance.

The effect of molybdenum (Mo) concentrations on the mechanical and magnetic properties of electrodeposited Co rich ternary CoMoW thin films from citrate electrolytic bath

Cobalt–Molybdenum-Tungsten (CoMoW) alloy thin films were prepared through an induced electroplating route from a citrate bath on the surface of the copper electrode at the controlled value of pH 8. The CoMoW thin films have been prepared by varying the Mo concentrations like 0.1, 0.2, 0.3 and 0.4 M at a deposition time of 30 minutes over a plating current potential of 40 mA / cm2. The electrodeposited CoMoW coatings have been investigated with the help of Field Emission Scanning Electron Microscopy (FESEM), powder crystal X-ray diffraction (XRD), Electrochemical studies (impedance and polarization) and Vibrating Sample Magnetometer (VSM) to reveal its respective microstructure-based information, mechanical and soft magnetic nature of the synthesized CoMoW thin layers. The CoMoW thin films of an HCP crystal structure have been attained. The induced electroplated condition such as Mo concentration has a significant impact on the crystal structure system, surface morphology, and soft magnetic performances. The crystalline size of the CoMoW thin layers has varied from 22.66 nm to 42.87 nm. The synthesized CoMoW thin layers were smooth, without cracks and had uniform morphology. All the electroplated CoMoW films have the highest Co content along with low Mo content (Co content gradually decreased while increasing the Mo content in the deposits) and thickness varied from 10 to 20 μm. Through the electrochemical investigation studies, it is concluded that the corrosion rate of CoMoW thin films was slightly increased by increasing the Mo content and the corrosion resistance varied from 80.2 KΩ to 92.7 KΩ. The CoMoW thin alloy films with higher Co content exhibited a lower coercivity value of 3.69 Oe and the saturation magnetization of 49.049 emu /cm2.

Material mechanisms of Cu/Ni nanolaminate coatings resulting in lifetime extensions of welded joints

Metal nanolaminate coatings are introduced as a new approach in post-weld treatment methods. A Cu/Ni nanolaminate coating is electrodeposited from a single Cu/Ni citrate bath onto a butt-welded tension-tension fatigue specimen. The nanolaminate coating consists of a Ni base layer and 160 alternating Cu and Ni layers. The specimen is tested in tension-tension fatigue with a stress range close to the yield strength of the specimen. This first study reveals surprisingly high lifetime extensions of welded joints. The tested specimens are examined using FIB/SEM and TEM. Local roughness measurements are carried out with AFM. This leads to observations on crack behavior of nanostructured Cu/Ni multilayers. The Cu layers show initial multi-crack formation, while the cracks arrest at the Cu/Ni interfaces. The Ni layers bridge those cracks and each Ni layer tears individually. Hypotheses are formed on the fatigue behaviour of Cu/Ni multilayers.