Sulfate Bath Research Articles

Electrodeposition of nano-diamond/copper composite platings: Improved interfacial adhesion between diamond and copper via formation of silicon carbide on diamond surface

Although copper is an effective heat-dissipation material, a material with a higher thermal conductivity is required to meet the demands of future electronics. Carbon materials (CMs) are of great interest owing to their excellent thermal conductivities; however, it is difficult to apply CMs individually because of their brittleness and low formability. CM/copper composites are expected to overcome these drawbacks. Diamond is of special interest for preparing composites because they do not require control of orientation owing to their isotropic thermal conductivity, but unfortunately, diamond and copper generally show poor interfacial adhesion. Therefore, designing an interface to improve their adhesion is essential to realizing high thermal conductivity. In this study, SiC-coated diamonds were adopted to fabricate diamond/copper composite platings by electrodeposition for the first time. Electrodeposition was carried out in a copper sulfate bath containing pristine and SiC-coated diamonds. The formation of SiC slightly decreased the current efficiency but did not significantly affect the diamond content of the plating. The sample with the nano-diamond/copper composite plating containing 1.07 mass% (2.72 vol%) of SiC-coated nano-diamonds exhibited a thermal conductivity 46 Wm−1 K−1 higher than that of the sample with pure copper plating. From observations of the diamond/copper interface using micron-sized diamonds as a model, an obvious gap was observed between the diamonds and the copper when using pristine diamonds, whereas no gaps were observed when using the SiC-coated diamonds. SiC formation significantly improved the adhesion between the diamonds and copper. In addition, copper was directly deposited onto the surfaces of the SiC-coated diamonds in contrast to pristine diamonds, which showed no sign of deposition.

Influence of Current Density on the Mechanism of Electrodeposition and Dissolution of Zn–Fe–Co Alloys

The electrodeposition of zinc–iron–cobalt alloys from sulfate bath was carried out galvanostatically on steel. A complementary approach based on of a combination of different electrochemical techniques was used to clarify the deposition mechanism. The electrodeposition of the alloys was of an anomalous type. The corrosion behavior of the coatings was evaluated from polarization measurements in hydrochloric acid. The deposition at different current densities exhibited varied influence on the corrosion potential of alloys obtained from sulfate baths. It was shown that increased corrosion protection of steel can be achieved by electrochemical deposition of ternary alloys with higher amounts of the Co and Fe. The composition of the ternary alloy can be optimized by proper choice of the current density.

Synthesis of methanol blocking PVA-TiO2 cation exchange membrane for direct methanol alkaline fuel cell

Polyvinyl alcohol (PVA) based cation exchange membrane has been synthesized for direct methanol alkaline fuel (DMAFC) cells by phase inversion technique coupled with chemical reaction. Nanocomposite membranes have been prepared by adding different amounts of titanium dioxide (TiO2) nanoparticles into the sulfonated PVA solution. PVA was sulfonated by sulfosuccinic acid solution. Sodium ion conducting membranes are formed by a typical chemical reaction induced phase inversion process, using a nonsolvent bath of sodium hydroxide (NaOH) and sodium sulfate (Na2SO4). The phase inversion technique coupled with chemical reaction significantly modified the chemical structure; improved thermal, mechanical, and surface properties of the sulfonated PVA based nanocomposite membrane. The mechanical and thermal properties of the membrane were investigated by UTM and TGA respectively. The chemical structure of membranes was analyzed by FTIR spectrometer. The presence of the TiO2 nanoparticles and sodium ions in the composite membrane was analyzed with the EDX technique. The surface morphology of membranes was studied by SEM micrographs. Moreover, water uptake, sodium ion conductivity, and methanol permeability of the membrane were altered with varying amounts of TiO2. Surface modified TiO2 nanoparticles enhanced the ionic conductivity of the composite membrane to the range of 10-−2 S/cm. Furthermore, the value of the methanol permeability was obtained in the order of 10-7 cm2/s.

Corrosion performance of Zinc Based Binary and Ternary Alloy Coatings

Abstract The binary (Zn-Ni, Zn-Co, Zn-Fe) and ternary (Zn-Ni-Co, Zn-Co-Fe) coatings have been developed with sulphamic acid (SA) as an additive using an electrolytic method of sulfate bath. The bath composition, pH, temperature, etc have been optimized using regular Hull cell technique. The effect of current density (C.D) on wt. % of metal, thickness (t), hardness (VHN), and cathode current efficiency (C.C.E) of the plating have been investigated. The potentiodynamic polarization technique has been used to determine corrosion resistances of binary and ternary alloy coatings. The corrosion rate (CR) of ternary Zn-Ni-Co alloy coating is about 18 times and 20 times higher as compared to binary Zn-Ni and Zn-Co alloy coatings and ternary (Zn-Co-Fe) alloy coating is also approximately 27 times and 28 times higher than Zn-Co and Zn-Fe coating at optimized conditions. Thus, ternary coatings can replace conventional binary alloy coatings for many technological applications including aerospace, automobiles etc.

Achieving exceptional tensile strength in electrodeposited copper through grain refinement and reinforcement effect by co-deposition of few layered graphene

Grain refinement which improves the mechanical strength of copper (Cu) results in substantial loss of its electrical conductivity. We demonstrate that synergistic effects of grain refinement and reinforcement of few layered graphene (Gr) can result in exceptionally high strength Cu without much degradation of electrical conductivity. For this study, the Cu-Gr composite foils are fabricated by pulsed electrodeposition from an additive-free copper sulphate bath. An aqueous suspension of few layer graphene, synthesized using a novel airless high-pressure exfoliation technique, was used as a reinforcement to copper. Electrodeposited pure Cu showed a strong columnar microcrystalline grain structure, and its grain size decreased slightly along with significant changes in the preferred growth direction upon increasing the current density and accordingly, the tensile yield strength improved moderately. Graphene reinforcement in copper resulted in significant grain refinement to ∼750 nm, increased growth-twin density and shift in crystallographic growth direction, and a remarkable tensile yield strength of ∼800 MPa which is much higher than previously reported values. The electrical conductivity of Cu-Gr composites was greater than 90% IACS and is comparable to pure copper. Detailed microstructural investigation and analysis suggest that uniformly dispersed graphene layers in conjunction with the reinforcement-induced microstructural features in electrodeposited Cu could have contributed to the observed high strength and good electrical conductivity.

Effect of graphene addition on composition, morphology and corrosion behavior of ZnNiFe-graphene composite coatings

Graphene reinforced, Zn-rich, Zinc-Nickel-Iron (ZnNiFe-G) coatings were deposited on mild steel substrate by electrolyzing the Zn-Ni-Fe acidic sulphate bath containing different amounts of dispersed graphene layers. Effect of graphene incorporation on composition, microstructure, morphology and electrochemical corrosion performance of coatings was investigated. X-ray diffraction studies revealed ZnNiFe coatings consists η Zn, γ Ni2Zn11 and Fe phases but the concentration of γ Ni2Zn11 phase increased with increasing graphene content in the coating. Incorporation of graphene enhanced the coating compactness and reduced the micro-pores and surface defects. Presence of graphene increased the Ni and Fe content in the coatings. The electrochemical corrosion behavior of the composite coatings was determined using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Increase in γ Ni2Zn11 phase concentration, compact and defect free ZnNiFe-G composite coatings exhibited >50% better corrosion resistance performance when compared to the corrosion resistance exhibited by the graphene free Zn-Ni-Fe coating. Among the ZnNiFe-G coatings, the composite coating with combination of highest Ni and graphene content showed the best corrosion resistance performance.

Morphology and composition of Zn–Ni alloy obtained from sulphate bath containing complexing agent

ABSTRACTZn–Ni alloys were electrodeposited on stainless steel from a sulphate bath in the presence of EDTA (ethylenediaminetetraacetic acid) as a complexing agent. The electrochemical behaviour of the bath was studied by cyclic voltammetry (CV), chronoamperometry (CA). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis showed a change in surface morphology; the phase structure corresponds to the face centre cubic (fcc) structure attributed to the γ phase (Ni5Zn21). The corrosion measurements of the obtained deposits with various EDTA concentrations were studied using potentiodynamic polarisation. Results showed that the deposit obtained in the presence of a low EDTA concentration (0.25 g L−1) exhibits better corrosion resistance.

Electrochemical Behavior, Structure, and Morphology of Electrodeposited Nickel on Copper Alloy Prepared from Sulfate Bath without Additive Addition

Nickel and nickel alloy has good chemical and physical properties to enhance corrosion resistance. Electrodeposited nickel layer are expected to enhance corrosion resistance of copper as substrates. The difference distance crystal plane of Nickel and Copper is about 0.02 – 0.03 Angstrom. The electrochemical behavior, structure and morphology of electrodeposited nickel on copper substrate in sulfate solution were investigated. Electrodepositions of nickel layer were conducted at room temperature with various current densities (10 mA/cm², 20 mA/cm², and 30 mA/cm²). Electrochemical behavior, structure, and morphology of the samples were analyzed by using potensiostat, x-ray diffraction (XRD), and Scanning electron microscope (SEM). The x-ray diffraction patterns show that the nickel has cubic FCC crystal system and space group Fm-3m. The current density during electrodeposition influence crystal parameter, crystallite size and micro strain of nickel film deposited. Electrodeposited nickel with current density 30 m A/cm² shows the best corrosion resistance.

Electroplated NiCo Alloy with Low Residual Stress from the Sulfate Bath

NiCo alloys are electroplated in sulfate bath. The concentration of cobalt sulfate and current density were varied to optimize the surface hardness. The properties of NiCo deposits were analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The surface hardness of the NiCo alloy was increased up to 500 Hv at 24 wt% Co in the deposits due to the grain refinement. The size of grain was reduced to 12 nm. The residual stress of the deposits was varied from tensile to compressive as the saccharin concentration increased. The zero residual stress was achieved at 0.05 g/L saccharin addition.

Effects of Bath Composition and P Contents on the Mechanical Properties of Ni-P Electroplating

Ni-P alloys are fabricated on the pre-cleaned copper substrate using electroplating method in sulfate bath. The concentration of phosphorous acid and current density were varied to optimize the P contents as well as the physical properties of the alloy. The properties of Ni-P alloy were analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The surface hardness of the Ni-P alloy was increased up to 550 Hv as the phosphorous acid (H3PO3) increased upto 0.015 M, however the higher phosphorous contents in the coating developed the cracked on the surface. The surface hardness was increased due the grain refinement.

Electro-Chemical Deposited Cu-Ni Binary and Cu-Ni-Mn Ternary Alloys from Sulphate Bath for Anti-Corrosive Coating Applications in Brine Environment: Effect of Corrosion Behaviour, Polarization Studies, Morphological and Structural Characterizations

Electrochemical preparation of binary alloy of Cu-Ni from acid sulphate bath containing citric acid using Potentiostatic method. The effects of alloy composition were monitored. Copper is widely used in industry, because of its good thermal conductivity and mechanical characteristics. The accumulation of Nickel & Manganese to Copper enhances itspotency, vigour, toughness, endurance, permanence&also the corrosion-resistanceas well asattrition. Corrosion controls of metal have technical environmental and economical importance. The Cu-Ni-Mn alloyswere used commercially for decorative and protective purpose and also in marine applications. The thin film coating characterized by SEM, EDAX and XRD shows morphological, compositional and structural properties of alloys respectively.

Enhancement in the corrosion resistance behaviour of amorphous Ni[sbnd]P coatings by incorporation of graphene

In the current study, amorphous nickelphosphorusgraphene (NiPG) composite coatings were electroplated on mild steel substrate. Coatings were electroplated from nickel sulphate bath containing phosphorus acid and exfoliated graphene in amounts of 50 mg/l, 100 mg/l, 150 mg/l, and 200 mg/l. Phase constitution, composition, surface morphology and corrosion parameters were investigated as a function of the graphene content. Experimental results exhibited that NiP and NiPG composite coatings possessed improved corrosion resistance than the mild steel substrate and addition of graphene enhanced the corrosion resistance performance when compared to the pristine coating. It was observed that an optimum exists with respect to the amount of graphene dispersed in the electrolyte bath for achieving high anti-corrosion property from the coating produced using the respective plating bath. Lower amount of graphene in dispersion produced uniform surface morphology which acted along with the graphene impermeability to yield high corrosion resistance performance. Higher quantity of graphene in dispersion, on the other hand, caused their agglomeration thus producing rough and defective surface morphology which along with non-uniform distribution of graphene yielded higher corrosion rates.

Process parameters affecting the efficiency of indium electrowinning results from sulfate baths

Since indiumisconsidereda strategic material, a study for developing and optimizing a recovery process by electrowinning has been performed. The possibility of using electrolytic baths based on sulfates instead of chlorides has also been evaluated. Nowadays, chlorides are widely used because they generally present greater current efficiencies;however, the dangers of chlorine gasrequireexpensive-sealed systems to avoid human health and environmental issues. The use of sulfatesdoes not present the same problems;therefore the electrowinning process optimization can represent a definite indium recovery improvement. For this purpose, the effects of electrolyte composition, temperature, current density and pH on the quality of the deposit, specific energy consumption (SEC) and current efficiency (CE) have been assessed. The sulfate electrolytic solutionhas been then appropriately modified with organic additives, mineral salts and complexing agents to optimize the indium recovery by electrowinning. ACE of about80% and SEC equal to 2.7 kWh/kg have been obtained, operating with a pH in the range 2.2–2.3 at 40 °C and using 25 A/m2 current density with an electrolytic solution containing 60 g/l of In3+, 30 g/l of Na2SO4, 20 g/l of Al2(SO4)3 and 20 g/l of H3BO3.

Effect of Baking on Hydrogen Embrittlement for High Strength Steel Treated with Various Zinc Based Electroplating from a Sulfate Bath

Effect of Baking on Hydrogen Embrittlement for High Strength Steel Treated with Various Zinc Based Electroplating from a Sulfate Bath

Electrochemical Performance of Nanocrystalline Zinc Ferrite Films Synthesized Using Electrodeposition

Nanocrystalline spinel zinc ferrite ZnFe2O4 thin film has been studied and synthesized via the electrodeposition-anodization process. Electrodeposited ZnFe2 alloys were obtained from aqueous sulphate bath. The resulted alloys were electrochemically oxidized in strong alkaline solution (1 M KOH) at room temperature to the analogous hydroxides. The electroanodized ZnFe2 alloy film was annealed in air at 400 °C for 2 h to get the required zinc ferrite. The electrochemical factors controlling of the electrodeposition of ZnFe2 alloys such as the bath temperature, agitation, the current density were studied and optimized. The crystal structure, crystal size and microstructure of the produced ferrites were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The deposited film was mainly composed of ZnFe2O4 based on XRD studies. The produced film had a spinel structure and the crystallite size was 4.9 nm. SEM micrograph of the resulted zinc ferrite particles shows compact crystallites shapes and agglomerated chains with smallest semicircular particles like morphology.

Effect of PDDA surfactant on the microstructure and properties of electrodeposited SiO2/Ni nanocomposites

In this study, SiO2/Ni nanocomposite coatings were electrodeposited from a sulphate bath with and without the addition of polydiallydimethylammonium chloride (PDDA) as a cationic surfactant. The surface morphology and microstructure on the cross-sections of the deposited nanocomposites were examined by scanning electron microscopy. More detailed microstructure characterization was performed using transmission, scanning-transmission and high-resolution transmission electron microscopy. It was determined that the addition of 2 and 3 mL/L of PDDA allows the incorporation of well-dispersed SiO2 nanoparticles in the crystalline nickel matrix. The distribution of SiO2 nanoparticles in the nanocomposite was visualized on elemental maps using energy dispersive X-ray spectroscopy in scanning-transmission mode. The size of nickel grains was determined by means of XRD, as well as image analysis of TEM images. The volume fraction of SiO2 clusters in the SiO2/Ni+PDDA nanocomposites with the addition of 2 and 3 mL/L of PDDA was equal to 16 and 27%, respectively. It was determined that improved quality nanocomposites electrodeposited in the presence of 3 mL/L of PDDA and 8 g/L of SiO2 exhibit high nanohardness, as well as good tribological properties and corrosion resistance.

Synthesis and characterization of CoFe2O4 thin films for solar absorber application

Spinel oxides synthetized by the electrochemical route can be used in different technological areas. In the present work, cobalt ferrite (CoFe2O4) thin films were deposited from sulfate bath on FTO-coated glass substrate by linear sweep voltammetry technique (LSV). We have investigated the effect of applied magnetic field B (AMF B) up to 0.5 T on the electrochemical response, the crystallographic texture, the morphology, the semiconductor type and the optical properties of the elaborated films. The structural and compositional analysis confirmed the synthesis of a well-crystallized CoFe2O4 with a good stoichiometry after an annealing treatment at 500 °C. Moreover, the CoFe2O4 films exhibited a p-type semiconductor as confirmed by the photo-electrochemical and Mott-Schottky tests. In addition, an increasing in the absorbance in the visible-UV region is observed under AMF B. Consequently, the magneto-electrodeposited CoFe2O4 thin films have a direct band gap energy of 1.5 eV.

Electrodeposited Ni–Fe–Cr2O3 nanocomposite coatings: A survey of influences of Cr2O3 nanoparticles loadings in the electrolyte

This work is concentrated on evaluating the relationship between concentrations of embedded Cr2O3 nanoparticles in the electrolyte and tribomechanical and corrosion properties of Ni–Fe alloy matrix coating what is a point of weakness in a vast majority of practical papers in this field. In addition, the paper assesses the changes in the phase structure and morphological features of Ni–Fe alloy coatings with inclusion of the nanoparticles and draws a meaningful interplay between these features and tribomechanical and corrosion properties of the deposits. The coatings were electrodeposited from a sulphate bath using direct current (DC). The results confirm that an incorporation of Cr2O3 nanoparticles can lead to improved properties, however the best outcome achieved when 6 g/L Cr2O3 nanoparticles incorporated into the electrolyte since the highest amount of the reinforcements embedded in the microstructure of deposits. According to the results, microhardness and charge transfer resistance of the alloy deposits increased by 170 HV and 22 kΩ cm2, respectively. On the other hand, the average coefficient of friction decreased by 0.15.

Fabrication of CNT/Cu Composite Yarn via Single-Step Electrodeposition

Carbon nanotube (CNT)/Cu composite yarns were formed via a single-step electrodeposition process. A twisted CNT yarn composed of multiwalled CNTs (MWCNTs) was used. Copper was directly electrodeposited onto the CNT yarn under galvanostatic conditions using copper sulfate baths with and without additives. Four additives (polyethylene glycol (PEG), chloride anion (Cl−), bis(3-sulfopropyl)disulfide (SPS), and Janus green B (JGB)) that are well known as “via-filling additives” were used together. The surface and cross-sectional microstructures of the copper-deposited CNT yarns were analyzed. Copper was electrodeposited only onto the surface of the CNT yarn from the bath without additives, resulting in a copper-coated CNT yarn. By contrast, copper was deposited not only onto the surface but also into the interior of the CNT yarn from the bath with the additives. The amount of copper deposited into the CNT yarn tended to increase with increasing PEG and Cl− concentrations. The current density also affected the size and location of the deposited copper particles. When the electrodeposition conditions were optimized, copper was relatively homogeneously deposited into the interior of the CNT yarn, resulting in a CNT/Cu composite yarn.

Development of Nanostructured Ni–Fe Alloy Coatings; Characterisation and Corrosion Analysis

The present investigation deals with the electrofabrication of nanostructured Ni-Fe alloy coatings on a mild steel using sulfate bath. The electrolytic bath composition and the current density of the coatings were optimized. Composition analysis by energy dispersive X-ray spectroscopy revealed that the Ni–Fe alloy coatings are of anomalous type. Potentiodynamic polarization corrosion test and electrochemical impedance spectroscopy methods in 3.5% NaCl solution direct towards the lowest corrosion rate at 4 A dm–2. Hardness and roughness of the coatings were evaluated using Vickers hardness test and atomic force microscopy, respectively. The surface morphological analysis of the coatings was characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy. The phase structure, the texture coefficient, and the crystallite grain size of the coatings were calculated and studied using X-ray diffraction.