Galvanic Deposition Research Articles

Application of UV-synthesized anion exchange membranes to improve nickel removal through galvanic deposition process

Nickel removal from sodium chloride solution has been studied in an electrogenerative cell and the effect of synthesized anion exchange membranes on the galvanic deposition process was investigated. As shown, although in the absence of the membranes, the highest electrical potential of 0.985 volts was achieved, nickel removal efficiency was the lowest. On the other hand, electrical potential as high as 0.976 volts was achieved from the galvanic cell when the UV-curable membrane was employed between the two galvanic cell compartments. Using such electrogenerative process facilitated by the advanced anion exchange membranes, 37.2% of nickel ions were spontaneously removed from a solution of 0.04 M NaCl containing 100 ppm initial nickel ions. Furthermore, the introduced UV-synthesized membranes revealed to have a rigid polymer network and sufficient mechanical and thermal stability with tensile strength of 26.9 MPa and degradation temperature of 415 °C.

Galvanic Deposition of Hydroxyapatite/Chitosan/Collagen Coatings on 304 Stainless Steel

The galvanic deposition method was used to deposit Hydroxyapatite/Chitosan/Collagen coatings on 304 stainless steel. Galvanic deposition is an alternative and valid way to fabricate bio-coatings with high biocompatibility and good anticorrosion properties. Physical-chemical characterizations were carried out to investigate chemical composition and morphology of the samples. Coatings consist of a mixture of calcium phosphate (Brushite and Hydroxyapatite) with chitosan and collagen. Corrosion tests were performed in the simulated body fluid (SBF) after different aging times. Results show that, in comparison with bare 304 stainless steel, coating shifts corrosion potential to anodic values and reduces corrosion current density. Nevertheless, the aging in SBF led to a completely conversion of brushite into hydroxyapatite. The release of metal ions, measured after 21 days of aging in SBF solution, is very low due to the presence of coating that slow-down the corrosion rate of steel.

Calcium phosphate/polyvinyl acetate coatings on SS304 via galvanic co-deposition for orthopedic implant applications

Abstract In this work, the galvanic deposition method is used to deposit coatings of brushite/hydroxyapatite/polyvinyl acetate on 304 stainless steel. Coatings are obtained at different temperatures and with different sacrificial anodes, consisting of a mixture of brushite and hydroxyapatite. Samples are aged in a simulated body fluid (SBF), where a complete conversion of brushite into hydroxyapatite with a simultaneous change in morphology and wettability occurred. The corrosion tests show that, compared with bare 304, the coating shifts Ecorr to anodic values and reduces icorr Ecorr, and icorr has different values at different aging times due to chemical interactions at the solid/liquid interface. The best performing deposits are those obtained by using Al as the sacrificial anode. The metal ion release, measured after 21 days of aging, is very low and is attributable to the presence of a coating that slows the steel corrosion. Coating cytotoxicity is investigated through cell viability assays with MC3T3-E1 osteoblastic cells. The results reveal a high cytocompatibility comparable to that of a pure cell culture medium.

Hydrogen sensing behaviour of platinum and palladium functionalized silicon nanowalls

In a chemi-resistive gas sensor, the sensing properties are essentially improved through surface functionalization. In the present work, silicon nanowalls (SiNWs) were carved on silicon wafers by metal-assisted chemical etching technique. Over the SiNWs, platinum (Pt) and palladium (Pd) nanoparticles were deposited through a fluoride-free galvanic displacement deposition technique. The surface-decorated SiNWs were then evaluated for their sensing behaviour towards hydrogen (H2) gas. The morphological investigation revealed vertically aligned SiNW architecture with Pt and Pd nanoparticles sprinkled over the wall-tips. The crystallographic analysis indicated that the SiNWs has the original single-crystalline nature of the silicon wafer even after surface modification. Comparison of H2 gas sensing efficacies indicates an ~ 8 and ~ 4-fold corresponding increase in Pd and Pt functionalized SiNWs, at 200 °C, with respect to pristine SiNWs. A plausible sensing mechanism is suggested with a suitable parallel resistance model. The combinatorial effect of single-crystalline SiNWs and catalytic properties of Pt and Pd resulted in enhanced sensing characteristics. Moreover, the economically scalable aptitude of the fabrication technique makes them suitable for real-time and facile industrial applications.

Свойства хромовых покрытий, нанесенных различными методами на циркониевый сплав Э110

The issue presents the results of studies of methods for increasing the corrosion resistance of fuel claddings made from zirconium alloy E110, performed at the SRC RF TRINITI, using coatings (Al, Al2O3, Cr) by pulsed laser deposition, as well as magnetron sputtering and galvanic deposition of chromium. Also presented some results of studies of adhesion, microstructure and corrosion resistance of chromium coatings deposited by various methods. It was revealed that the corrosion resistance of the cladding of fuel rods with chrome coatings at temperatures of 1100 – 1200 °С practically does not depend on the method of their application. However, the coating method has a significant effect on their adhesion, with coatings obtained by atomic deposition methods and characterized by a continuous uniform structure have the greatest adhesion. The depth of oxidation of the outer surface of the cladding of a fuel rod when applying a chromium coating decreases by an average of 30 times for sponge-based alloy E110.

X-ray fluorescence determination of zinc sulfate in acidic zinc plating electrolyte

Zinc sulfate is the main component in the composition of the acidic zinc plating electrolyte. Deviation in the electrolyte composition from the optimum content leads to destabilization of the electrolysis process and deteriorate the quality of the resulting zinc coating. The proper quality of a zinc coating obtained by galvanic deposition can be ensured only with timely monitoring and adjustment of the electrolyte composition. A technique of X-ray fluorescence determination of zinc (in terms of zinc sulfate) in an acidic zinc plating electrolyte is proposed. The study was carried out using an ARL Quant’X energy dispersive spectrometer (Thermo Fisher Scientific, USA) with a semiconductor silicon-lithium detector. The features of the spectrometer design are presented. The optimal parameters of excitation and detection of zinc radiation were specified when the electrolyte sample was diluted 1:1000. The ZnKα1 line was used as an analytical line. The plotted calibration graph is linear, the correlation coefficient being 0.999234. The results of zinc determination according to the developed method were compared with the data of the reference method of complexometric titration to prove the reliability of the procedure. The results are characterized by good convergence and accuracy. The proposed method of X-ray fluorescence zinc determination in a zinc plating electrolyte equals complexometric titration in the limiting capabilities and even exceeds the latter in terms of the simplicity of sample preparation and rapidity. The developed method of X-ray fluorescence determination of zinc is implemented in analysis of the electrolyte used in the continuous galvanizing unit at «METSERVIS LLC».

Controlled morphology and dimensionality evolution of NiPd bimetallic nanostructures

Controlling the morphology of noble metal-based nanostructures is a powerful strategy for optimizing their catalytic performance. Here, we report a one-pot aqueous synthesis of versatile NiPd nanostructures at room temperature without employing organic solvents or surfactants. The synthesis can be tuned to form zero-dimensional (0D) architectures, such as core–shell and hollow nanoparticles (NPs), as well as nanostructures with higher dimensionality, such as extended nanowire networks and three-dimensional (3D) nanodendrites. The diverse morphologies were successfully obtained through modification of the HCl concentration in the Pd precursor solution, and the reaction aging time. An in-depth understanding of the formation mechanism and morphology evolution are described in detail. A key factor in the structural evolution of the nanostructures was the ability to tune the reduction rate and to protonate the citrate stabiliser by adding HCl. Spherical core–shell NPs were formed by the galvanic replacement-free deposition of Pd on Ni NPs which can be transformed to hollow NPs via a corrosion process. High concentrations of HCl led to the transition of isotropic spherical NPs into anisotropic wormlike nanowire networks, created through an oriented attachment process. Aging of these nanowire networks resulted in the formation of 3D porous nanodendrites via a corrosion process. The diverse structures of NiPd NPs were anchored onto acid treated-activated carbon (AC) and exhibited improved catalytic efficiency towards the hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP).

Microstructure of combined electroless and galvanic deposits on roll annealed copper foils and copper single crystals

The production of highly flexible printed circuit boards requires copper plating on roll annealed (RA) Cu foils with strong (001) crystallographic orientation, with electroless copper plating followed by galvanic copper plating. Concurrent epitaxial and polycrystalline crystal growth during galvanic plating has to be avoided because it leads to unacceptably rough sample surfaces, with polycrystalline regions protruding. Two electroless plating processes are compared in terms of their interaction with the subsequent galvanic plating step. Plating tests are carried out with RA substrates and (111), (011) and (001) copper single crystals. Crystallite orientation distributions are determined by measuring X-ray diffraction pole figures for the substrates, as well as the substrates with galvanic deposits, electroless deposits and combined electroless and galvanic deposits. One of the electroless processes creates Cu {111} planes parallel to the sample surface, thereby reliably disrupting epitaxy between the substrate surface and the growing galvanic film. Moderate constant stress in the electroless processes enables good mechanical adhesion to the substrate.

Copper nanowire array as highly selective electrochemical sensor of nitrate ions in water

Contamination of water with nitrate ions is a significant problem that affects many areas of the world. For this reason, European legislation has set the maximum permissible concentration of nitrates in drinking water at 44 mg/L. Thus, it is clear that a continuous monitoring of nitrate ions is of high technological interest but it must be rapid, easy to perform and directly performable in situ. In this work we have developed a nanostructured sensor based on array of copper nanowires obtained with the simple method of galvanic deposition. The nanostructured sensors have a very short response time with a detection limit less than 10 μM. Different interfering species were tested finding a negligible effect except for the chloride ions. However, this problem has been solved by removing chloride ions from the water through a simple precipitation of chloride compounds with low solubility. Nanostructured sensors were also used to analyze real water samples (rain, river and drinking water). In the case of drinking water, we have measured a concentration of nitrate ions very close to the that measured by conventional laboratory techniques.

Structure and Magnetic Properties of Layered Nanowires of 3d-Metals, Fabricated by the Matrix Synthesis Method

Based on PET track etched membranes, arrays of layer nanowires 100 nm in diameter, consisting of alternating Ni/Cu and Co/Cu layers are grown by the matrix synthesis method. Galvanic deposition processes are studied and conditions for fabricating layer nanowires with different thicknesses for magnetic (Ni or Co) and nonmagnetic (Cu) layer components are determined. An electron microscopic study is performed to verify conditions for fabricating layer nanowires and to correct geometrical sizes of alternating layers. Magnetization curves of produced arrays of layer nanowires are measured by vibration magnetometry methods at room temperature for two extreme orientations of a scanning magnetic field, i.e., parallel and perpendicular ones with respect to the nanowire growth axis. It is shown that the magnetic anisotropy of the nanowire array is controlled not only by the chemical composition, but also the thickness and alternation period of magnetic metal layers in nanowires. The dependence of the magnetostatic energy and demagnetizing field in the synthesized layer nanowires on the magnetic metal filling factor is numerically evaluated; the results are in qualitative agreement with experimental observations.

New insight into Pt nucleation mechanism on Si surface during galvanic displacement deposition

Platinum nanostructures are of large interest because of their electrocatalytic properties, enhanced by the high surface/volume ratio, and find applications in numerous fields from fuel cells and electrolyzers, to gas biosensors and nano-biomedicine.In this work we present a simple procedure, based on spontaneous galvanic displacement, to obtain Pt nanoparticles (PtNPs) directly on Si substrate. The nucleation and growth processes involved in the deposition have been studied by Transmission Electron Microscopy and Rutherford Backscattering Spectrometry. The nucleation is quite complex and includes, first, the generation of primary non-growing clusters, with size smaller than 2 nm. Then, for longer deposition times, larger particles are formed, resulting from dynamic coalescence of primary clusters with/or single ion attachment processes. The growth of such larger particles follows the prediction of the classical diffusion limited model. Moreover, the large nanoparticles are poly-crystalline and exhibit a nano-porous structure, in agreement with a mixed aggregative-diffusion limited growth. The nano-porous structure implies a high internal surface area, therefore making these particles particularly promising as efficient catalysts.

Energy-Inexpensive Galvanic Deposition of BiOI on Electrodes and Its Conversion to 3D Porous BiVO4-Based Photoanode

The present work focuses on energy neutral, bias free, scalable galvanic synthesis of highly crystalline thin films of BiOI on a fluorine doped tin oxide (FTO) electrode (BiOI/FTO). Electrodes as d...

The Significant Effect of Supporting Electrolytes on the Galvanic Deposition of Metallic Rhenium

The Significant Effect of Supporting Electrolytes on the Galvanic Deposition of Metallic Rhenium

Use of Electroplating for Increasing the Efficiency and Quality of Impregnation of a Porous Graphitized Carbon Material with Copper Alloys

The possibility of increasing the efficiency and quality of the gasostat-free impregnation of porous graphitized carbon materials with copper alloys by galvanic deposition of thin metallic alloying coatings on the surface of a graphitized carbon sample is studied. An electrodeposited coating made of high-purity copper (up to 99.9% Cu) in combination with other metals, which is preliminarily deposited onto the surface of a porous graphitized carbon base, is shown to significantly increase the filling of pores with a matrix melt and to a decrease the impregnation temperature from 1250 to 800°C. This finding makes it possible to use low-temperature furnace equipment and simple technological equipment and to produce high-quality composite materials.

Study of structural and morphological features of nanostructured coatings based on CoCdSe

The paper presents the results of a study of the effect of the applied potentials difference on the properties of thin films based on CoCdSe. It is shown that the use of the galvanic deposition method allows not only controlling the thickness of the synthesized films by changing the applied potentials difference, but also changing the stoichiometric and phase composition of thin films. It was found that an increase in the applied potentials difference leads to the domination of the CoSe phase in the structure of thin films, leading to structural ordering and a decrease in the dislocation density of defects and an increase in the density of thin films. It was found that the formation of the CoSe phase in the structure of thin films and its subsequent increase leads to a shift in the band gap from 3.5 eV to 3.8 eV. The change in the band gap is caused by a change in the phase composition, as well as stoichiometry of thin films, with a predominance of cadmium in the structure. The prospects of using thin films based on CoCdSe as the basis for photocatalytic reactions are shown.

Comparison study of gold coatings prepared by traditional and modified galvanic replacement deposition for corrosion prevention of copper

Gold coating is one of the choices to prevent copper circuit in PCBs from corrosion. Although galvanic replacement deposition is supposed to be a convenient method to prepare gold coating on copper circuit, compact gold coating is hard to be obtained through traditional galvanic replacement deposition. In this work, gold coatings were prepared on copper substrates through traditional and modified galvanic replacement deposition. According to the SEM, EDS, XPS and XRD tests, the gold coating prepared by traditional galvanic replacement deposition had lots of micropores and nanopores, and Cu-Au solid solution phase was generated on copper substrate other than the gold phase. Therefore, the gold coating prepared by traditional galvanic replacement deposition could not prevent copper substrate from corrosion, but slightly increased the corrosion current density of copper substrate in 3.5 wt% NaCl solution owing to the galvanic corrosion. However, compact gold coating could be obtained through modified galvanic replacement deposition, in which aluminum foil was contacted to the copper substrate to form galvanic couple and donated the electrons for the deposition of gold instead of the copper substrate. The SEM, EDS, XPS and XRD tests demonstrated the gold coating prepared by modified galvanic replacement deposition was compact and mainly composed of pure gold phase. The gold coating prepared by modified galvanic replacement deposition obviously enhanced the corrosion resistance of copper substrate, and it reduced the corrosion current density of copper substrate in 3.5 wt% NaCl solution to 1.773 μA·cm−2 from 87.40 μA·cm−2 with the corrosion inhibition efficiency of 98.0%.

Electrochemical Copper Deposition on Nanoscale-Sculptured Aluminum for Mechanically Stable Joints with Optimal Electrical and Heat Transport Properties

Copper is a material with a very high conductivity per volume; therefore it is widely used in the industry for nearly every electric application. However, with respect to weight aluminum (due to its low density of 2.7 g/cm3) shows a significantly higher electrical conductivity than copper. For many lightweight applications, aluminum would be the preferred material, but it lacks for good technical solutions for forming easy to apply, corrosion resistant, highly conductive contacts to (other) metals, especially to copper. Many of these problems are related to the native aluminum oxide coating on all aluminum surfaces in contact to air. State of the art solutions for electrical contacting aluminum surfaces require high temperatures and/or high pressure, thus making them expensive and typically damage the surface near microstructure of the aluminum.In this abstract, we will discuss details of a room temperature technique, which allows for a mechanically stable, corrosion resistant, galvanic copper deposition on aluminum surfaces with extremely high interface conductivity for heat as well as for electrical current. This allows the application of standard bonding technologies for copper (e.g. soldering or using conductive glues) onto aluminum as a conducting material.The copper deposition technique contains three steps: 1. A special surface preparation, i.e. nanoscale-sculpturing (cf. [1]) which creates a low corrosive aluminum surface structure full of mechanical hooks, composed of 100 crystallographic facets.2. A preconditioning step before galvanostatic copper deposition.3. Galvanic copper deposition controlling the nucleation of copper islands within the hooking structure and the morphology of the growing copper layer.Due to the nanoscale-sculpturing, the deposited copper is mechanically stable bonded to the aluminum surface. Dependent on the demands for subsequent bonding applications, the galvanic copper deposition must be adjusted; e.g. for gluing, large parts of the hook like structure from the underlying aluminum surface should still exist after a thin layer of copper is deposited.In contrast, for soldering application, a robust and thick layer of copper is needed.How the nanoscale-sculpturing and the galvanic copper deposition can be adjusted to various application will be discussed in detail.[1] Baytekin-Gerngross, M., Gerngross, M., Carstensen, J. and Adelung, R. (2016). Making metal surfaces strong, resistant, and multifunctional by nanoscale-sculpturing. Nanoscale Horizons, 1(6), pp.467-472.

Durability of the “Coating–Base” Composition during Rolling Friction

In this paper, we study the effect of various physical and mechanical properties, chemical and phase compositions of diffusion coatings of steels on the durability of tribosystems during rolling friction with point and linear contacts in an I-20 oil medium. Gradient coatings obtained by ion nitriding in anhydrous media and titanium and chromium nitride coatings, respectively, obtained by cathode-ion bombardment and galvanic deposition on steels with various levels of hardness after heat treatment were considered. The main factors affecting the contact endurance of coated steels and ways to increase the durability of tribosystems during rolling friction were identified in comparative tests using friction machines. A direct linear dependence of the durability of the coating-base composition on the hardness of the base for steels without metastable structures in the material and a deviation from this dependence toward increasing durability for steels with residual austenite in the structure of the material were established.

Reexamination of Nucleation and Growth Behavior of Zn during Zincating on Al: Role of Nitric Acid Etching

Deposition of various coatings on Al surface is required for variety of functional applications such as for better corrosion resistance, improvement in conductivity, wear resistance etc. These coatings are normally applied on Al surface followed by well-known zincating process (galvanic displacement) in order to obtain subsequent adherent overlayer coatings. Adhesion of these overlayers depends on uniformity of Zn films on Al surface and researchers normally follow either single zincating or double zincating process to eliminate oxide layer interference. However, it has been established over the years that double zincating is a better technique in comparison to single zincating to produce a uniform Zn-films on Al surface. It is to mention here that Al substrate undergoes nitric acid dip followed by single zincating prior to double zincating and is a very important step. A quiet good amount of research has already been devoted to obtain various adherent coatings on Al and Al-alloys and to analyze the nucleation mechanism during single and double zincating processes. However, the underline mechanism of nitric acid etching and its role on subsequent Zn-nucleation is yet to be fully understood. In view of this, in the present study, a systematic effort has been made to elucidate the role of nitric acid etching followed by single zincating on Zn nucleation and growth mechanism during subsequent second zincating. For this, we have studied the time-dependent zinc nucleation on 99.95% pure Al during single as well as double zincating. These Zn-nucleation and growth behavior on Al surface was monitored using AFM, FESEM and FIB-cut cross section image investigations in detail. Difference in nucleation and growth pattern of Zn on Al during two zincating processes was analyzed. Apart from these, the porous surface obtained after nitric acid dissolution was investigated in depth under AFM and FESEM along with EDS. Non-gravimetric method such as Rutherford Backscattering Spectrometry (RBS) was used to determine the deposition rate of Zn during competitive galvanic deposition of Zn and alkaline dissolution of Al while zincating. The Zn grain size obtained from AFM image was verified by GIXRD analysis. Open circuit potential (OCP) was monitored during single as well as double galvanic displacement processes to understand Zn nucleation behavior and correlated with the morphological data. The observed results will be discussed in terms of electrochemical processes involved, change in chemical nature of the Al surface and porous layer formation due to nitric acid etching and thermodynamic supersaturation on Zn nucleation. Figure 1

(Invited) In Situ Studies of the Atomic Structure/Charge Distribution at the Electrochemical Interface

The presence of specifically adsorbed anions can significally affect the electrochemical reactivity of a metal electrode which is of major interest for galvanic deposition, etching, corrosion and electrocatalysis. Halogens on metal surfaces are prototypic adsorbate systems but the adsorption of halide ions especially on copper is also of major importance for on-chip metallization in ULSI microchip production. Halide ions on Cu surfaces form an inhibiting adsorbate layer with polyethylene glycol (PEG). Even though the influence of the additives combination on the shape evolution of the Cu deposit was subject of numerous studies, their precise role during the elementary steps of the deposition with regards to altering the charge distribution and dipole moment at the interface is largely not understood.To obtain insights into the influence of the applied potential and the screening by the electrolyte to better understand electrochemical processes and charge transfer during adsorption and deposition is a major goal .[1]Thus combining x-ray spectroscopy and x-ray diffraction to gain site-specific information about the charge distribution at buried interfaces is a promising tool. [2,3]We will present studies on the metal-halide interface and how the use of surface x-ray scattering techniques can help to characterise electrochemical interfaces in-situ in order to link, structure and stability. [3] Advances in these directions offer possibilities in elucidating atomic scale models of the electrochemical interface and thus will help to establish structure-stability-reactivity relationships which will help to understand growth kinetics.