Copper Sulfate Electrolyte Research Articles

A mathematical model of the copper plating process in restoration of road transport equipment parts

Introduction. The use of restored parts of motor vehicles makes it possible to reduce the financial costs of repairing equipment. The cost of the restored parts should not exceed 50% of the cost of the new part. Increasing the productivity (deposition rate) of an electrolytic copper coating during the restoration of parts of motor vehicles requires taking into account the technological and economic aspects of the restoration process. The study of the factors (deposition conditions) that most affect the deposition process of the copper coating, the analysis of the experimental results and its statistical processing made it possible to optimize the technology of restoration of copper parts to create the most appropriate deposition modes with maximum productivity, thus reducing the cost of restoration of parts of motor vehicles. The purpose of the research is to develop a mathematical model of the effect of deposition conditions (electrolyte temperature, cathode current density) and electrolyte composition (concentration of copper sulfate and sulfuric acid) on the performance of the deposition process of copper coating, for further development of the most productive technology for restoring collectors of electric motors of motor vehicles.Materials and methods. The studies on equipment that allows obtaining the necessary data with the required accuracy were carried out. Mathematical processing using modern statistical data processing tools that excluded possible errors, providing to obtain the dependence of factors with the necessary accuracy was carried out.Results. In the course of studies of copper sulfate electrolytes to obtain an electrolytic copper coating, with the further development of technology for the restoration of automotive parts, it became necessary to determine the effect of deposition conditions – “factors” (cathode current density, electrolyte temperature, copper sulfate concentration, sulfuric acid concentration) on the deposition rate – “response”. It was found that the factor “cathode current density” and the combination of factors “cathode current density” and “sulfuric acid concentration” are the most significant. The deposition conditions in order to obtain the most productive technology for restoring collectors of electric motors of motor vehicles by depositing a copper coating have been optimized. According to the obtained model, the optimal values of the deposition conditions for obtaining the maximum deposition rate are the electrolyte temperature of 35...40 ° C, the cathode current density of more than 5 A/Dm2, the concentration of copper sulfate 200...250 g/l, the concentration of sulfuric acid 40...70 g/l.

Analysis of the influence of local electrodeposition conditions on the accuracy of electrochemical 3D-printing

Problem. Additive manufacturing of metal parts by local electrodeposition is a new promising area with several unique features. The use of electrolysis makes it possible to manufacture metal parts at room temperature with high accuracy and low energy consumption. The accuracy and speed of electrochemical 3D printing are inversely related, and therefore it is important to find optimal electrodeposition conditions at maximum speed without degrading accuracy. The aim of the study. The purpose of this work was to analyse the influence of electrodeposition parameters (electrode distance, electrical conductivity and electrolyte polarization) on the accuracy of metal deposit formation in a computer model and to conduct experimental verification of optimal conditions for electroforming a real object from copper sulphate electrolyte. Methodology of implementation. To achieve the goals of the study, computer simulation of the electrochemical deposition process in the COMSOL Multiphysics software and electrochemical measurements of the characteristics of copper sulphate electrolytes were used. Research results. Computer simulation established optimal conditions: the distance between the edge of the capillary and the surface on which deposition occurs is not more than 0.5 mm, the electrolyte in which the inverse slope of the cathode polarization curve is not lower than 2000 mA/(V×cm2) and the electrical conductivity is not higher than 0.02 S/сm. The influence of the electrolyte composition on the inverse polarization of the cathode process and its electrical conductivity was investigated. The optimal composition of the electrolyte was selected, containing 200 g/L CuSO4, 60 g/L H2SO4, 0.2 g/L KCl and RUBIN T-200 additive. In the selected electrolyte, the value of the inverse slope of the cathode polarization curve is 2120 mA/(V×cm2). Verification of the process of local electrodeposition in the selected electrolyte during the electroformation of a cylindrical object with a diameter of 4 mm and a height of 100 μm was carried out. It was determined that no more than 5 % of metal was deposited outside the capillary of the working electrode. Conclusions. The results of the work can be used to create an electrochemical 3D printing system. Further research should be aimed at approbation of the obtained parameters of local electrodeposition in an installation that simulates the operation of a 3D printer and establish the accuracy and speed of printing of a three-dimensional object. Key words: additive manufacturing, electrical conductivity, electrolyte composition, polarization, local electrodeposition.

Additive concentration and nozzle moving speed influence on local copper deposition for electrochemical 3D-printing

The local deposition process from copper sulfate electrolyte was investigated depending on nozzle moving speed and additive concentration in the electrolyte. A 2×2 cm square model was created and sliced in Ultimaker Cura software, uploaded in a 3D printer, and printed from the copper electrolyte on the stainless-steel surface. Low additive concentration in the electrolyte was found to influence dendrite formation in the corner sections of a square model. Nozzle movement speed was found to influence the deposition area and the thickness of the metal. The lowest tested nozzle movement speed of 5 s / voxel increased the deposition area by nearly 40 % in horizontal direction compared to 2.5 s / voxel. Further increase of nozzle movement speed to 1.6 s / voxel does not change the deposition area. The thickness in the corners increases by 2.5 times compared to the straight section of the square when the nozzle movement speed increases from 5 to 1.6 s / voxel. The non-uniform thickness of the deposited metal is caused by a considerable reduction of nozzle movement speed when it moves through the corner. The results obtained in this work can be further used to develop electrochemical 3D printing technology.

Control of Crystallographic Growth Orientation and Twinning Structure in Copper Nanowires by Template-Assisted Electrodeposition

Synthesis and characterization of noble metal nanowires have been a popular topic in the field of microelectronic devices and catalysts. Nanotwinned copper nanowires (nt-CuNWs) possess high mechanical strength, excellent electromigration resistance and low electrical resistivity, which have been considered as a promising interconnect material in ultra-large scale integrated circuits (ICs). Here, we deposited nt-CuNWs in two different anodic aluminum oxide (AAO) templates with respective pore sizes of 70 nm and 35 nm pore by pulse electrodeposition. The influence of thermal treatment on the Cu seed layer deposited on AAO membranes prior to electrodeposition is investigated. Both coarse and thin nt-CuNWs mainly grew in <111> crystallographic direction with (111) texture coefficients (TC(111)) > 2.5, and an aspect ratio (AR) > 100 according to x-ray diffraction analysis. An addition of gelatin (14 ppm) in the copper sulfate electrolyte is found to suppress the growth of (220)-oriented Cu grains in the AAO by forming copper nanowires with large TC(111) > 2.65 and high-density nanotwin structure. This study provides a simple route to tailoring microstructure and physical properties of nanoscale copper wires, which is beneficial for the interconnect technology development in semiconductor IC devices.

Growth, characterization, and photovoltaic application of copper oxide thin films

• CuO was obtained from the annealing of Cu 2 O electrodeposited on SnO 2 :F electrodes. • Optical properties were modeled in the visible and near-infrared ranges. • Photoelectrochemical measurements confirmed a possible absorber layer application. • CuO samples have presented a strong photocurrent generation. This work presents the fabrication of Cu 2 O thin films using electrodeposition at room temperature. These have been grown using a copper (II) sulfate electrolyte (pH=10) on fluorine-doped tin oxide films. Thermal oxidation at standard atmosphere was applied to obtain CuO samples from Cu 2 O. The characterization of these copper oxide samples has revealed their morphological, compositional, crystalline, vibrational, and optical properties. These results indicate the desired features for photovoltaic conversion applications. Moreover, strong photocathodic current generation in these samples has been found using chronoamperometry. In addition, first-principles calculations based on generalized gradient approximation, in a Perdew-Burke-Ernzerhof parametrization, were performed to determine the structural, electronic, and optical properties of these copper oxides to help in the interpretation of the experimental results.

Local electrochemical deposition of copper from sulfate solution

Local electrochemical deposition is a type of electroplating used to plate metal locally or form metal objects using electrochemical principles at a short distance from the working electrode. In this work, deposition of the copper spot was modelled using COMSOL software and experimentally tested in copper sulfate electrolyte using soluble copper anode. The working capillary diameter was 4 mm and the interelectrode distance was 5 mm. The deposited copper of 100 µm height was investigated using the 3D-profilometry technique. The geometry of deposited metal was found to be in good accordance with the COMSOL model. The inclusions of anodic sludge were responsible for the surface inhomogeneity of the deposited copper.&#x0D;

Preparation and characterization of Cu-GO and Cu-GO-YSZ nanocomposite coating by electrochemical deposition for improved mechanical and anti-corrosion properties

Graphene oxide (GO) and yttria-stabilized zirconia (YSZ) nanoparticle reinforced copper (Cu) matrix nanocomposite coatings were successfully fabricated via direct current electroplating from a copper sulfate electrolyte. Influences of particle concentration (GO/YSZ) in electrolyte, electrodeposition time and applied current density on composition, microstructural and anti-corrosion performance of Cu-GO and Cu-GO-YSZ composite coatings were explored. The corrosion behaviors were evaluated by electrochemical measurement. Results indicated the composite coatings exhibit a uniform and compact surface which was made up of stacked granules, exhibiting morphologies that nanoflake-like structures dispersed on the pyramid-like copper matrix granule clusters network. The crystallite sizes of Cu-GO first increased and then decreased as GO, time and current density increased, while it varied little for Cu-GO-YSZ composite coating. The preferred orientation of Cu matrix composite coating was oriented (220) texture. The content of incorporated GO increased with the introduction of YSZ into the Gu-GO matrix. The Gu-GO coating contains 93.3 wt% Cu and 5.5 GO, and the Gu-GO-YSZ coating contains 91.7 wt% Cu and 7.6 wt% GO. The average roughness Ra of Cu-GO and Cu-GO-YSZ were 240 ± 7 nm and 236 ± 40 nm, respectively. The addition of GO nanosheets could improve the microhardness and decrease the COF of Cu matrix. Both self-lubrication effect and load-bearing capability were improved by introducing GO and YSZ together in the Cu matrix. Deposits obtained at 30 mA cm−2, 30 min, 0.1 g L−1 GO and 10 g L−1 YSZ particles own the optimal corrosion resistance with the maximum Rp. It reveals that corrosion resistance was enhanced by the presence of GO nanosheets in Cu matrix for physical isolation effect of GO and the preferred orientation (220) plane, which benefited the formation of passive film.

Two-Step Electrochemical Route to Synthesize Nanostructured Cu2O Thin Films

The conversion of solar energy to chemical fuels via a photoelectrochemical (PEC) cell is one promising approach to produce clean energy. A PEC cell consists of two light absorbing electrodes with appropriate optoelectronic properties. Depending upon the band alignment, one of two electrodes is a photoanode producing O2, and the other one is a photocathode which produces H2. One such suitable photocathode for a PEC cell is Cu2O; an intrinsic p-type semiconductor with a direct bandgap of 2.0 eV and a high absorption coefficient of 104 cm-1 in the visible range. Its conduction band minimum (CBM) lies 0.7 V negative of water reduction potential and therefore, can act as a photocathode. However, one major challenge associated with Cu2O is its poor minority carrier diffusion length resulting in a large recombination rate in bulk and lower overall cell efficiency. In this aspect, nanostructured materials are of great use owing to their inherent properties. Orthogonal charge separation, enhanced light absorption, and large electrode-electrolyte are few advantages of the nanostructured materials which can be used to overcome the issue of minority carrier diffusion length. However, the synthesis of nanostructured Cu2O thin films is quite challenging as it involves multiple steps and/or require high-temperature processing.In this work, we present a low temperature, and straightforward two-step synthesis method to obtain nanostructured Cu2O with 10-30 nm thick nano-walls on FTO coated glass substrate. First, the Cu2O thin films are electrodeposited at a potential of -0.35 V vs. Ag/AgCl in a pH 12 lactate stabilized copper sulfate electrolyte at 55 °C. The electrodeposited Cu2O films are 1.3 µm thick and show pyramidal grains of size up to 2 µm on the surface after a deposition period of 15 mins. Later, these films are subjected to voltage cycling in a potential range of -0.6 V to 0.6 V (vs. Ag/AgCl) in a pH 5 electrolyte comprised of 0.5 M Na2SO4 and 0.1 M K2HPO4 at RT. This causes top 0.5 µm of deposited films to reconstruct to 10-30 nm thick nano-walled porous morphology after 20 cycles of voltage cycling. The voltammogram shows that reconstruction is a concomitant etching of Cu2O as Cu2+ ions along with oxidation to CuO. In fact, a potentiostatic hold at anodic potentials leads to porous CuO. This porous CuO is reduced back to Cu2O during the cathodic part of the voltage cycling. Interestingly, the number of cycles performed during voltage cycling is found to affect the phase purity of the material. The XRD scans reveal that Cu2O films are phase pure only up to 50 cycles. However, phase purity is no longer preserved as Cu impurity is detected in Cu2O films post 50 cycles. A comparison of linear sweep voltammetry (LSV) scans of pristine Cu2O, and CuO thin films show that reduction of Cu2O to Cu is a slow process in this potential range, and hence, Cu-impurity is not observed up to 50 cycles. The bare nanostructured Cu2O film show a photocurrent of -2.0 mA-cm-2 at a potential of 0.3 vs. RHE in a pH 5 media, which is almost 1.5 times of the dense Cu2O. This enhancement in photocurrent is attributed to efficient separation of photogenerated charge carriers in the orthogonal direction, increased electrode-electrolyte contact area, and enhanced light trapping. The photocurrent can further be improved via coating with wide bandgap metal oxide layers such as AZO/TiO2. Such a facile fabrication technique can be utilized to prepare nanostructures of various metal oxides on a large scale for their application in PEC cells and other optoelectronic devices. Figure 1

MODELLING APPROACH IN THE DEVELOPMENT OF ELECTROCHEMICAL 3D-PRINTING SYSTEMS

Background. New 3D-printing technologies are becoming more and more advanced and widespread in the twenty-first century. One of the types of 3D-printing is electrochemical 3D-printing, in which electrochemical deposition of metals is used to form metal products. Potentially, this method of 3D-printing is the most energy efficient, the least material-intensive, and also the easiest to implement. There- fore, research aimed at creating and improving systems for electrochemical 3D-printing is promising. Objective. The aim of the paper is to study the influence of geometric parameters of the system and the composition of the elec trolyte on the current distribution on the surface of the working electrode (cathode) in the process of electrochemical 3D-printing, and therefore print accuracy. Methods. Volt-amperometric measurements and multi-physical computer modelling of the secondary distribution of current density using COMSOL MULTYPHYSICS for different geometric parameters of the working part of the 3D-printer and different composition of electrolytes. Results. Based on the simulation of the secondary distribution of current density in copper sulphate electrolyte, it was found that the content of sulfuric acid in the solution should be minimal in order to purposefully deposit metal in the area directly under the working electrode. Based on the condition of maximum energy efficiency and accuracy of electrochemical 3D-printing, the optimal ratio between the deposition surface (cathode) and the edge of the non-conductive body of working electrode was found. Conclusions. It was established that in order to narrow the zone of current scattering (increase the accuracy of electrochemical 3D-printing) it is necessary to ensure the optimal ratio between the diameter of the capillary and the edge of the non-conductive body of the counter electrode. It was shown that this ratio should not be less than 5 [mm / mm]. Further applied research will be aimed at adaptation and practical implementation of the obtained model data, optimization of the electrolyte composition and design of the 3D-printer.

Preparation of Gr-Reinforced Cu Foil: A Challenge to Ultrathin Thickness

A layered Cu/Gr/Cu ultrathin foil via a one-step electrochemical route A layered structure has a better effect on improving performance of the graphene (Gr)-reinforced composites due to its unique two-dimensional structure and excellent properties. In this work, a novel “one-step” electrochemical route was proposed for synthesizing the Gr-reinforced ultrathin copper (Cu) foil with high performance. The process includes: 1) A loose graphene oxide (GO) membrane, was prepared by electrophoresis deposition (EPD), that allows Cu ions passing through; 2) According to the difference of Cu deposition potential on different substrates, a potential step was designed for electrodepositing Cu successively on both sides of the GO membrane, i.e., the bottom Cu layer forms under low over-potential, while the top Cu layer forms under high over-potential. The experimental results show that the foil thickness reaches to as thin as 4-5 μm, and the tensile strength is almost twice as large as that of pure Cu foil. This process is simple, controllable and possible mass production, and expected to further practical applications in fields of Cu clad plate, printed circuit board and lithium-ion battery cathode collector system for saving raw material and also the space. In addition, this work proposes a new idea for preparing the layered composites via electrochemical route. A Cu-(CNTs+Gr) composite ultrathin foil via electrodeposition The incorporation of nano-reinforcement, such as carbon nanotubes (CNTs) and graphene (Gr), into copper (Cu) matrix via electrodeposition is a promising method to improve its comprehensive property. However, the challenge is to achieve a uniformly suspended electrolyte with these reinforcements or surfactant due to their inferior dispersibility. In this work, we report a process to produce a kind of high performance Cu-(CNTs+Gr) composite foil by using hybrid self-dispersing reinforcement CNTs+Gr via a direct current (DC) electrodeposition, which further results in an ultrathin foil reach to the thickness as low as 4 μm. In this process, firstly, the precursor graphene oxide (GO) with amphipathicity acts as a surfactant-like substance and disperses CNTs uniformly through the π-π bonding in-between GO and CNTs in the copper sulfate electrolyte. Then, GO is reduced into Gr during electrodeposition, and the synergistic effects of CNTs and Gr play a key rule to improve the ultrathin Cu-(CNTs+Gr) composite foil’s properties, including tensile strength up to 436 MPa, inoxidizability and superior electrical conductivity. This work provides a possibility to have mass-production of Cu foil as thin as 4 μm in industry and broad applications in the future.

Investigation on the corrosion resistance of the CuO-Al2O3 composite coating prepared by micro-arc oxidation

A CuO-Al2O3 composite coating was obtained by an AC deposition and a followed secondary MAO treatment in an acidic copper sulfate electrolyte and an alkaline sodium hexametaphosphate electrolyte. Analyzes on phase and elemental composition and microstructure showed that a continuous CuO layer was formed on the top of the original MAO coating. EIS test suggested that after a secondary MAO treatment for 1 min, the samples obtained by AC deposition for 5 min had the best corrosion resistance, because of the barrier of CuO layer to the NaCl solution.

Electroplating coatings on complex profiled models made of conductive and current-conducting plastic

The possibilities of the conductive and nonconductive composite plastics to be used for the complex profiled models made by the 3D prototyping in galvanoplastics are studied. A dissipating ability of the electrolyte by current and by metal using a Mohler slot cell was studied and applied, a visual study of samples was performed, and the weight and thickness of the metal deposited at different parts of the complex profiled surface of the samples was determined both of conductive and nonconductive plastics. The structure of the conductive plastic must ensure the uniformity of the electrical resistance of the material. The weight and size features of the models made of the conductive plastics for electroplating are determined. The optimal parameters of the process of electrochemical formation of the galvanoplastic copper deposits from copper sulfate electrolyte are defined. The advantages and disadvantages of the use of the conductive and nonconductive models are revealed resulting from a comparative analysis. The features of the process of galvanic coatings’ formation are determined for both cases. It is shown that, in the process of the galvanic manufacturing of the products, it is necessary to take into account a high adhesion of the deposited metal to the surface of the models made of the conductive plastic.

Effect of zinc ions on copper electrodeposition in the context of metal recovery from waste printed circuit boards

This paper evaluates the effect of zinc ions on copper electrodeposition. Although zincis not found at significant concentrations in conventional industrial copper electrolytes, in copper-concentrated sulfate leach liquors produced in the treatment of waste printed circuit boards (WPCB) its concentration may reach high levels. In this context, the effect of zinc on physical-chemical properties of copper sulfate electrolyte, performance indicators of copper electrowinning, and morphology and crystal structure of copper deposits were investigated. Copper electrowinning tests indicated that the current efficiency was negligibly affected by adding zinc (up to 75 g L−1) to synthetic copper sulfate electrolyte (30 g L−1 Cu2+ and 110 g L−1 H2SO4) at two levels of current density (250 A m−2 and 450 A m−2) and fixed temperature (35 °C). The energy consumption slightly increased: up to 4% at 250 A m−2 and up to 3% at 450 A m−2, both effects at 75 g L−1 Zn2+. This behavior was ascribed to decreases in the electrical conductivity of the electrolyte by adding zinc (up to 35% at 75 g L−1) and consequent increases in the ohmic drop and cell voltage. Electrochemical measurements by cyclic voltammetry and linear sweep voltammetry (LSV) indicated no cathode polarization by adding this impurity to the electrolyte, even at the highest level. In turn, the addition of zinc caused significant drops in the limiting current for copper deposition (e.g., the values recorded at 100 min−1 decreased about 60% when 75 g L−1 Zn2+ was added to the electrolyte). This effect was explained by the measured increases of electrolyte viscosity and calculated decreases of copper diffusion coefficient. The addition of 75 g L−1 Zn2+ to the electrolyte increased its viscosity in the order of 76%, and decreased the diffusion coefficient in the order of 45%. Regarding the effect of zinc on product quality, SEM analysis revealed negative effects on the morphology of the deposits (i.e., higher roughness and nodulation), mainly at the highest concentration of zinc and highest current density. XRD analysis showed modifications in the growth pattern of copper crystals under some conditions. For example, the addition of 30–75 g L−1 Zn2+ to the electrolyte led to the formation of (220) textured deposits at 250 A m−2. The findings of this work may be helpful to define proper operating conditions for copper electrowinning in order to produce high quality products, thus maximizing the recycling of copper from the selected secondary source.

Stainless steel substrate pretreatment effects on copper nucleation and stripping during copper electrowinning

The effects of surface pretreatment of 304 stainless steel (SS) substrates on copper film formation, adhesion, and purity obtained by galvanostatic electrodeposition at a current density of – 30 mA cm−2 are presented. The polished substrate produced more copper nuclei, resulting in an increase of the adhesion as compared to chemically oxidized SS substrate. The adhesion of the copper deposits was characterized by a Nano-scratch tester (NST). The nucleation behavior is associated with the flatband potential of the SS surface, which was derived from capacitance measurements. The grain size of copper deposits was characterized by field emission scanning electron microscopy (FESEM). Copper grains were smaller on the polished SS with a size of less than 1 µm after 5 min of electrodeposition. High-purity copper deposits with < 1 ppm S (detection limit) were obtained on the oxidized SS substrate compared to 2.5 ppm for the polished SS substrate. Atomic force microscopy (AFM) measurements showed that the copper deposits were 25% less rough on the polished SS as compared to the oxidized SS. The results indicate that the obtained purity of the copper deposit relates to the grain size of the deposit, rather than the initial surface roughness. In the context of industrial electrowinning, high adherence to the polished substrate could increase the operation time of the copper cathode stripping. Hence for electrowinning from copper sulfate electrolytes, oxidizing the SS surface prior to deposition could lead to higher purity along with enhanced stripping.

Effect of Current Density on Crystallographic Orientation, and Oxidation Behavior of Copper Plated on Aluminum Substrate

In this work, the electroplating of copper on an aluminum substrate without electrochemical surface treatment was investigated. Electroplating of copper on aluminum substrate was prepared from copper sulfate electrolyte bath with various current densities 1 mA/cm², 3 mA/cm², 10 mA/cm², and 40 mA/cm². The effects of current density on the samples properties were characterized using a different technique. The surface morphology, crystallographic orientation, and corrosion resistance of the Copper film were analyzed using a scanning electron microscope, energy dispersive spectroscopy (SEM-EDS), X-ray diffractometer (XRD), and potentiostat. The samples' surface morphology is changed with different current densities because nucleation is driven by transferring the copper ion rate onto the aluminum substrate. The Cu-10 sample exhibits (111) peak higher and the best corrosion resistance than other samples. Moreover, Cu-1 samples have shifted to positive corrosion voltage (Ecorr) than the other samples.

ПРИМЕНЕНИЕ ИЗОТИУРОНИЕВЫХ СОЛЕЙ В КАЧЕСТВЕ БЛЕСКООБРАЗУЮЩИХ ДОБАВОК ПРИ МЕДНЕНИИ

The behavior of various isothiuronium salts as brighteners in copper sulphate electrolyte has been studied.

Effect of transient low-grade solar heat on liquid thermogalvanic cells

Thermogalvanic cells have attracted huge attention for the conversion of low-grade waste heat into electricity due to their cost effectiveness. The environment in itself is a rich source of untapped energy such as energy from the sun, geothermal waste heat etc. However, the transient nature of this waste heat makes it a challenge for all-day electricity generation. This paper therefore seeks to investigate the effect of the transient nature of the ultra-low-grade solar energy on liquid thermogalvanic cell. Copper sulphate (CuSO4) electrolyte and copper electrodes were used. The electrolytes were contained in two pyrex 100-ml glass beaker with corks holding the electrode and a thermocouple in each beaker. A 42 cm long tube containing same electrolyte connected the two as a salt bridge. The electrolyte concentrations were varied from 0.2 to 1.0 M at a temperature difference ranging from 2 to 10 °C. The maximum Seebeck coefficient of 0.698 mV/K was recorded at a concentration of 0.8 M CuSO4 during heating and 0.798 mV/K at a concentration of 1.0 M during cooling. A maximum power output of 3.99 nWcm−2 was obtained at a concentration of 0.8 M.

Synergistic effect of Gr and CNTs on preparing ultrathin Cu-(CNTs+Gr) composite foil via electrodeposition

The incorporation of nano-reinforcement, such as carbon nanotubes (CNTs) and graphene (Gr), into copper (Cu) matrix via electrodeposition is a promising method to improve its comprehensive property. However, the challenge is to achieve an uniformly suspended electrolyte with these reinforcements or surfactant due to their inferior dispersibility. In this paper, we report a process to produce a kind of high performance Cu-(CNTs+Gr) composite foil by using hybrid self-dispersing reinforcement CNTs+Gr via a direct current (DC) electrodeposition, which further results in an ultrathin foil reach to the thickness as low as 4 μm. In this process, firstly, the precursor graphene oxide (GO) with amphipathicity acts as a surfactant-like substance, and disperses CNTs uniformly through the π-π bonding in-between GO and CNTs in the copper sulfate electrolyte. Then, GO is reduced into Gr during electrodeposition, and the synergistic effects of CNTs and Gr play a key rule to improve the ultrathin Cu-(CNTs+Gr) composite foil's properties, including tensile strength up to 436 MPa, inoxidizability and superior electrical conductivity, This work provides a possibility to have mass-production of Cu foil as thin as 4 μm in industry and broad applications in the future.

Effect of Polyethylene Glycol and Chloride Ions on Local Electrochemical Deposition of Micro Copper Columns

Local electrochemical deposition (LECD) is a very promising three-dimensional (3D) metal microstructure fabrication method. To fabricate smaller and better micro structures, a 20 μm micro anode and suppressor were used to reduce the diameter of a micro copper column and improve its surface morphology. Micro copper columns were deposited with a copper sulfate electrolyte, with or without polyethylene glycol (PEG) and chloride (Cl−) ions. The morphology and size of all deposited columns were analyzed at the same voltage, and the deposition mechanisms with PEG and Cl− were discussed. Results indicated that the 20 μm micro anode formed a micro copper column of diameter 30-40 μm, and the use of PEG and Cl− further decreased the diameter to 28.1 μm.

Nano SiC Reinforced Copper Nanocomposite by a Simple Electrodeposition Method

The Cu and Cu-SiCnanocomposite coatings were prepared by a simple electrodeposition technique from acidic copper sulphate electrolyte using SiC nanoparticles with an average particles size of 50 nm under optimized bath composition and preparation conditions for possible electrical contact material applications such as electrical switch and wiring boards where higher electrical conductivity and thermal conductivity is required. The scope of the present study is to enhance the strength, mechanical, corrosion and wear resistance properties of Cu-SiCnanocomposite compared to pure Cu coatings. The as prepared Cu and Cu-SiCnanocomposites were characterized for structural, mechanical and corrosion resistance properties by EDX, XRD, FESEM, Vickers microhardness tester and AC-impedance and Tafel polarization techniques. The elemental composition (wt% of Cu and SiC nanoparticles) of Cu-SiCnanocomposites was analyzed by EDX coupled with FESEM analysis confirms the presence of nanoSiC in the copper matrix and they were 89wt% of Cu and 11 wt% of SiC nanoparticles respectively. The surface morphology of Cu and Cu-SiCnanocomposites was studied by FESEM analysis shows that SiC nanoparticles were uniformly dispersed in the surface of the copper matrix compared to pure copper. The crystallite structure and grain size of the Cu and Cu-SiCnanocomposite electrodeposits was measured by XRD analysis. From the XRD results, the grain size calculated using Debye-Scherrer’s formula was ~35 nm for pure Cu and ~33 nm Cu-SiCnanocomposite. The crystallite structure of Cu and Cu-SiCnanocomposites was fcc (face centered cubic) and the preferred orientation of the plane was (220). The microhardness of Cu-SiCnanocomposite coating increased with increasing SiC nanoparticles concentration in the bath compared to pure Cu coating. The corrosion resistance measurements were performed for the pure Cu and Cu-SiCnanocomposite coatings by electrochemical impedance spectroscopy (EIS) and Tafel polarization techniques. It shows that, Cu-SiCnanocomposites has high corrosion resistance than pure Cu in 3.5wt% NaCl solution.