Sulfate Bath Research Articles

(Digital Presentation) Anti-Corrosion Investigation of Titanium Electrode for Cu Plating

For the plating of Cu in many industrial applications, Ti metal is commonly used as the cathode for the reduction of Cu. Titanium metal is known to exhibit adequate corrosion resistance due to the formation of a thin passivation layer on the surface. Under an acidic and high temperature environment, the passivation layer on the surface of the titanium metal tends to react with acidic solution. In other words, Ti metal tends to be corroded in an acidic environment. The corrosion behavior of commercial pure titanium in acid copper sulfate baths was investigated in this study. Available surface treatments were applied to suppress the corrosion of titanium passive layer. The microstructure of titanium metal after immersion in acid copper sulfate solution was examined by using SEM and FIB. The pitted and corroded Ti was clearly observed using SEM. The corrosion mechanism of the titanium metal in the sulfuric acid solution was discussed. In addition, the electrochemical characteristics of commercial pure titanium metal in sulfuric acid solution were also analyzed using the three-pole potential measurement method.

Estimating Electrodeposition Properties and Processes: Cu-Ag Alloy at n-Si(001) and Ru Substrates from Acidic Sulfate Bath

A simple method for estimating the composition and duration of the initial stage of alloy electrodeposition is important for deposition process design and the deposit characterization. Analytically or numerically solving the complete diffusion-migration-convection problem based on common simulation methods could be difficulty to be implicated as an ordinary task for designing alloy electrodeposition parameters and electrolytes.In this work, we have proposed some simple estimations for the initial stage of Cu-Ag alloy electrodeposition, at Si(001) or polycrystalline Ru, regarding (1) the potential-composition curve, (2) the thickness of the initial deposit, and (3) the time interval to reach the steady state deposition, based on the stagnant diffusion layer model. The limiting deposition current is compared with the numerical results from Selman and Newman in 1970s [1]. Meanwhile, composition of the film deposited under limiting current with various electrolyte chemistries is compared with the model suggest by Brenner [2]. Despite the model proposed in this work are highly simplified and not precisely realistic, estimated values show good agreement with the observed values. Reference: [1] J.R. Selman, J. Newman, Migration in Supported Electrolyte Solutions with Free Convection, (1971).[2] A. Brenner, 11 The Role of the Cathode Diffusion Layer in the Electrodeposition of Alloys, in: A. Brenner (Ed.) Electrodeposition of Alloys, Academic Press1963, pp. 307-330. Disclaimer: This work has been published at Electrochimica Acta, 403:139695 with title "Estimating electrodeposition properties and processes: Cu-Ag alloy at n-Si(001) and Ru substrates from acidic sulfate bath". Figure attached is chosen from this manuscript. Figure (a) Observed and estimated composition-potential curve for Cu-Ag electrodeposition system. (b) Film thickness v.s. deposition time, and (c) film thickness v.s. composition of the film, from which Ag-rich initial deposit was observed. Figure 1

Electrochemical Corrosion Behaviour of Nickel and Nickel-Reduced Graphene Oxide Coatings on Mild Steel in 3.5% NaCl Solution

Nickel-based electrodeposits are extensively used to protect mild steel. The graphene-based materials as corrosion resistive coatings for metallic substrates have been attracted researchers due to their ability to prevent the metal surface. Herein, nickel and nickel reduced graphene oxide (Ni-rGO) composite coatings have been electrodeposited on mild steel using sulphate bath solution. The morphological results reveal that the Ni-rGO coatings exhibited a smaller grain size with less surface defects. It was observed from the scanning electron micrographs images that composite coatings are porous free. The anti-corrosion properties of coatings were further examined by salt spray test. The electrochemical polarization and impedance measurements revealed that Ni-rGO coating enhances the corrosion resistance of mild steel. Electrochemical measurements revealed that the insertion of a few-layered rGO to the Ni matrix increases the corrosion resistance properties of the Ni-rGO coatings.

Catalytic impact of Sm2O3 nanoparticles on the electrodeposition of zinc-nickel alloy

A variety of chemical compounds have been utilized as additives to develop the characteristics and the mechanical properties of electrodeposited zinc-nickel alloy plating. Zinc-nickel alloy plating was electrochemically deposited on a steel substrate from an acidic sulphate bath, containing Sm2O3 nanoparticles. The obtained results showed that the addition of small amounts of Sm2O3 causes a considerable shift in the polarization curve as well as the deposition potential towards greater noble potentials, demonstrating that Sm2O3 has a catalytic impact on Zn2+and Ni2+ reduction. The Ni content in the alloy was found to be 7.07–25.45 wt% depending on the operating conditions. The zinc-nickel alloy deposited electrochemically comprised of two phases, pure zinc, and Ni5Zn21, according to the XRD observations. The Sm2O3 incorporated in the Zn–Ni coating was detected using XPS (X-ray photoelectron spectroscopy) analysis. The data showed that zinc-nickel alloy coating prepared from an electrolyte containing Sm2O3 had a corrosion resistance higher than that prepared in its absence. On the other hand, the microhardness of zinc-nickel alloy plating was critically enhanced with Sm2O3 in the electroplating solution, it increased from 62.0 kg f mm−2 to 151.00 kg f mm−2. Changing the operating conditions such as temperature, pH, and current density have a considerable impact on the morphology of the zinc-nickel plating.

Optimization of indium electrowinning from sulfate solutions on Ni cathode

The indium recovery via electrowinning from sulfate baths has recently gained significant attention due to the absence of toxic emissions, sealed-system requirements, human health and environmental hazards. In the present research, Ni has been considered as a cathode for indium electrowinning from sulfate baths. The influence of process parameters, temperature, pH, current density, electrolyte composition and additive additions on specific energy consumption (SEC), current efficiency (CE), as well as deposit morphology has been evaluated. The findings indicate that the indium electrowinning using Ni cathode at 40 °C temperature, 2.3 pH, 70 g/L In3+ as sulfate, 5 g/L H3BO3, 30 g/L Na2SO4 and 20 g/L Al2(SO4)3 electrolyte composition maintained a high CE of about 98% and low SEC of about 1.7 kWh/kg from 25 to 80 A/m2 current density. While increasing current density up to 100 A/m2, a maximum of about 83.3% CE with 2.4 kWh/kg SEC are obtained if 40 g/L and 30 g/L of boric acid and sodium sulfate are used, respectively. In the optimized conditions, indium deposits exhibited a lamellar morphology and crystallographic tetragonal structure.

Butynediol’s Role beyond Brightening Additive during Electrodeposition of Cobalt

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

Investigation of Cu-graphite composites prepared by electroforming

Abstract In this work, Cu-graphite composites were prepared by electroforming technology in an acidic copper sulfate bath with graphite particles in suspension. The factors affecting the codeposition of graphite particles with copper were studied. At a particle concentration of 20 g l –1, a current density of 3 A dm– 2 and a stirring rate of 100 min–1 graphite content in the composites was 21.7 vol.%.Microhardness and friction coefficient of the composites decreased with increasing graphite content. However, wear mass-loss decreased, but increased with graphite content above 21.7 vol.%. The wear mechanisms of pure Cu and Cu-graphite composites were adhesive wear and delaminating wear, respectively.

Electro-galvanization of zinc and zinc-nickel onto mild steel for improved corrosion resistance

Pure zinc was electroplated on mild steel sample at specific potential and current density from sulphate bath and its characterization was done by various techniques. Corrosion rate of coating was found using potentio-dynamic polarization technique. Corrosion rate of coating was improved using alloyed coating (zinc-nickel).The main objective was to replace hot-dip galvanization technique with electro-galvanization so as to reduce thickness of coating and also to do away with problem of heat affected zone arising in hot dip galvanization, further enhancing the corrosion resistance of electro-galvanized coating by using alloying elements.Pure zinc was deposited on mild steel via electrodeposition technique at potential and current density values of −1.45 V, −1.55 V, −76 mA/cm2, −97 mA/cm2 respectively. Thickness of coating was measured using surface profilometer. SEM images and XRD data were taken and analysed and finally corrosion rate was calculated using Tafel extrapolation. Further zinc-nickel was electrodeposited on mild steel sample at −1.45 V and −1.55 V and corrosion rate of coating was compared with pure zinc coating.It was observed that for pure zinc coating as the deposition potential increases from −1.45 V to −1.55 V, the corrosion resistance is enhanced. With addition of alloying elements such as nickel the corrosion resistance of coating was slightly increased and also coarse grain structure was obtained when SEM images were compared.

Electroplating of Zn at different current densities onto mild steel for improved corrosion resistance

The main objective was to replace hot-dip galvanization technique with electro-galvanization so as to reduce thickness of coating and also to do away with problem of heat affected zone arising in hot dip galvanization, further enhancing the corrosion resistance of electro-galvanized coating by using alloying elements.Pure Zinc was electrodeposited on mild steel (MS) sample at specific current densities i.e. at −50, −150, −250 mA/cm2 from sulphate bath and its characterization was done by various techniques. The deposition current/ potential obtained by a systematic cyclic voltammetry study. Corrosion rate of coating was found using potentio-dynamic polarization technique and corrosion mechanism was obtain by Electrochemical Impedance Spectroscopy (EIS) analysis. Thickness of coating was measured using surface profilometer and was found to be in the range of 13 µm to 29 µm. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) data were taken and analyzed and finally corrosion rate was calculated using tafel extrapolation. Best corrosion result was found at −150 mA/cm2 current density.The corrosion resistance of coating was slightly increased and also coarse grain structure was obtained when SEM images were compared.

Electrochemical codeposition of arsenic from acidic copper sulfate baths: The implications for sustainable copper electrometallurgy

• The main source of arsenic contamination is codeposition during the nucleation stage. • Convection and concentrated Cu(II) electrolytes mitigate arsenic contamination. • The reduction of As(III) to metallic As does not occur readily. • Fast removal of As(III) possible by copper-arsenic codeposition. Copper producers face increased demand associated with increasing complexity in feedstock composition, including high amounts of impurity metals. In this work, linear sweep voltammetry was used to study the electrodeposition behavior of copper and arsenic, define strategies for the production of grade A copper, and the removal of arsenic from complex electrolytes. Our results show that the copper concentration is a key parameter to control in the electrodeposition process. The continuous deposition of arsenic from the electrolyte requires copper in solution (≤10 g L −1 Cu(II) for 2 g L −1 As(III)) to form copper arsenides . The deposition of metallic arsenic does not occur readily. Conversely, the use of a concentrated Cu(II) solution (e.g. 40 g L −1 ) resulted in grade A copper from an electrolyte with a maximum of 2 g L −1 As(III) under galvanostatic control at a current density of – 42 mA cm −2 . Time-of-Flight Secondary Ion Mass Spectrometry depth profile measurements on copper deposits revealed that arsenic contamination was entirely concentrated near the substrate side of the deposit and progressively decreased further into the deposit. The codeposition of arsenic occurred along with the initial copper nucleation, when the electrochemical potential for electrodepostion under galvanostatic control is temporarily lower. These findings provide important insights for future sustainable copper electrodeposition technologies from complex feedstocks.

Effect of Al particle size on the microstructure and wear properties of the co-deposited Ni-Al composite coatings

Micrometer and nanometer Al particles were codeposited with nickel by electrodeposition from a nickel sulfate bath containing a similar content of Al particles. The microstructure, the friction and wear performance of the co-deposited Ni-Al composite coatings were comparatively evaluated. The results indicated that the co-deposition of smaller nanometer Al particles with Ni effectively reduces the size of Ni crystals and significantly increases the hardness of the composite coatings due to grain-refinement strengthening and dispersion-strengthening, resulting in a significant improvement of wear resistance of the Ni-Al nanocomposite coatings. The effect of Al particles size on the microstructure, friction and wear resistance is discussed in detail.

Electrodeposition of Cu-Ag Alloy Films at n-Si(001) and Polycrystalline Ru Substrates

Electrodeposition of Cu-Ag films from acidic sulfate bath was conducted at n-Si(001) and polycrystalline Ru substrates. Significant nucleation overpotential of 0.4 V is observed with the Cu-Ag bath at n-Si(001) substrate, whereas the electrodeposition of Cu-Ag at Ru substrate is influenced by Ru oxides at the surface. Incomplete coverage of Si substrate by Cu-Ag deposit was observed from the deposition systems without Ag(I), or with 0.1 mM Ag(I), comparing with the compact Cu-Ag film obtained with the deposition bath containing 0.01 mM Ag(I). Layered and faceted Cu-Ag deposit was observed at small Cu deposition overpotential with the Ru substrate. Phase composition of the Cu-Ag deposits at n-Si(001) substrate from electrolyte with various Ag(I) concentrations is examined by XRD. Limited solubility of Ag (0.4 at.%) was observed in fcc-Cu until phase separation occurs. The classical model for nucleation kinetics in electrodeposition was used to examine the potentiostatic transients of the Cu-Ag electrodeposition at n-Si(001) substrate.

Estimating electrodeposition properties and processes: Cu-Ag alloy at n-Si(001) and Ru substrates from acidic sulfate bath

In alloy electrodeposition, estimations of the initial transient and the potential vs. composition trend of the film system is important for material design, deposition procedure and the deposit characterization. However, solving the diffusion-migration-convection problem based on common simulation methods is often too burdensome and too resource-consuming for ordinary tasks in the context of alloy electrodeposition works. In this work, based on a stagnant diffusion layer model, we have proposed simple estimates on (1) the potential-composition curve, (2) the thickness of the initial deposit, and (3) the time interval to reach the steady state deposition. These estimates were validated by using a Cu-Ag acidic sulfate electrolyte, which upon electrodeposition results in an immiscible Cu-Ag alloy, both at n-Si(001) or at polycrystallline Ru substrates. The limiting current of Cu-Ag electrodeposition is compared with the numerical results given by Selman and Newman in 1970s [17], whereas the film composition deposited at the limiting current from various electrolyte constitutions is compared with the model suggest by Brenner based on stagnant diffusion layer model [21]. The proposed estimation methods show good agreement with the observed values, despite being highly simplified, since they are compared with the actual mass-transfer problem of ions under convection and migration.

Fabrication of Robust Superhydrophobic Nickel Films on Steel Surface With High Corrosion Resistance, Mechanical and Chemical Stability

Abstract Superhydrophobic films were successfully grafted on a steel substrate using potentiostatic electrodeposition of nickel followed by treatment with myristic acid (MA) as a low surface energy material. A scanning electron microscope (SEM) was used to investigate the surface topography of the prepared superhydrophobic films. The results revealed that the prepared Ni films modified by myristic acid have micro-nano structures. Fourier transform infrared spectrophotometer (FTIR) and X-ray diffraction (XRD) measurements showed that the steel substrate was coated with nickel film modified with myristic acid. Three different nickel films were prepared: the Ni-MA (I) deposited from pure nickel sulfate bath (1.0 M NiSO4), Ni-MA (II) deposited from pure nickel chloride bath (1.0 M NiCl2. 6H2O), and the third Ni-MA (III) film deposited from Watts bath (0.2 M NiCl2. 6H2O and 0.8M NiSO4). The superhydrophobic Ni-MA (I) film has the highest corrosion resistance, chemical stability, and mechanical abrasion resistance, while Ni-MA (II) film has the lowest properties.

Effect of TiO2 Concentration on Microstructure and Properties of Composite Cu-Sn-TiO2 Coatings Obtained by Electrodeposition.

In this work, Cu–Sn–TiO2 composite coatings were electrochemically obtained from a sulfate bath containing 0–10 g/L of TiO2 nanoparticles. The effect of TiO2 particles on kinetics of cathodic electrodeposition has been studied by linear sweep voltammetry and chronopotentiometry. As compared to the Cu–Sn alloy, the Cu–Sn–TiO2 composite coatings show rougher surfaces with TiO2 agglomerates embedded in the metal matrix. The highest average amount of included TiO2 is 1.7 wt.%, in the case of the bath containing 5 g/L thereof. Composite coatings showed significantly improved antibacterial properties towards E. coli ATCC 8739 bacteria as compared to the Cu–Sn coatings of the same composition. Such improvement has been connected with the corrosion resistance of the composites studied by linear polarization and electrochemical impedance spectroscopy. In the bacterial media and 3% NaCl solutions, Cu–Sn–TiO2 composite coatings have lower corrosion resistance as compared to Cu–Sn alloys, which is caused by the nonuniformity of the surface.

Effect of organic additives and current efficiency on electrodeposition of Nickel from sulfate bath

The properties of nickel metal electrodeposited in presence of organic additives in various concentrations were studied with respect to current efficiency of the bath. Films were electrodeposited in various pH and temperatures and for different time in order to get high current efficiency and uniform deposit. Locally available salt of sulfate is preferably used as source of nickel. Sodium sulfate is used to improve the conductivity of the bath and it is found that the rate of deposition linearly increases with the increase in concentration of the sodium sulfate in the electrolytic bath. Nickel chloride is primarily added to the bath not only to increase the corrosion of the anode but also to enhance the uniformity of the deposited layer. Surface structure analyses were carried out using scanning electron microscopy. Elemental analyses are done by energy dispersive x-rays. Reasons for variation in properties and structural characteristics of metal deposit are discussed.

An investigation on corrosion properties of bright Zn‐Ni alloy coated mild steel

AbstractIn the present work, the electrodeposition of Zn–Ni alloy from Sulfate bath was carried out in presence of a novel brightener (CG), the condensation product of Cysteine Hydrochloride and Glutaraldehyde. The corrosion studies were carried out using Electrochemical Impedance spectroscopy and Potentiostatic techniques. They confirmed an increase in corrosion resistance and protection ability of bright zinc–nickel alloy coatings. Surface morphology was studied using SEM, FTIR, and reflectance spectroscopy that revealed fine‐grained nature of Zn‐Ni alloy crystallites. X‐ray diffraction studies were used for phase identification and preferred orientation of Zn–Ni alloy crystallites. The preferred orientation of the Zn‐Ni alloy crystallites along (630) planes was configured for bright appearance of the coating. CG was successful in giving an even, homogeneous, refined, and bright Zn‐Ni alloy deposit.

Investigations on Surface Behavior of Electro-Less Nickel Phosphorus Coatings with Nano Additives on Magnesium Alloy Used In Automotive Applications

To enhance the damage and corrosion behaviour for alloys, the coating is found because of the maximum fitted technique. Mg-based alloys have a good range of business application. These alloys show a high specific strength but bad attire and corrosion resistance. A standard coating of Cu, Ni & Zn etc. provides a physical barrier against the wear and tear rate and corrosion attack of magnesium substrate. In the recent study, plating Ni-P was thru going on AZ91 composite by immersing samples into Nickel sulphate bath in the existence of surfactants. The study of the mechanism of Ni-P deposits was studied utilizing SEM. Ni-P coating was coated consistently within the existence of surfactants. Result of surfactant and Result of Nano-additives ZnO, Al2O3 and SiO with various quantities were examined. 0.5 g/l Nano Al2O3 additive-enhanced the deposition of Ni-P on AZ91 magnesium composite and hereafter the similar consequences are detected just in case of SiO accumulation. Effect of ZnO was also noticed. So is extremely clear that Ni-P coating is extremely effective to scale back the corrosion and rise the wear and tear behaviour if it's used together with Nano additive and therefore the surfactants.

Influence of zinc sulfate concentration in baths on the structure, morphology and tribocorrosion properties of Fe-Zn alloy coating

To address the glazing issue of impregnated diamond bit in drilling hard and compact rock formations, Fe-Zn alloys were electrodeposited from acid sulfate baths and the surface morphology , phase composition, microhardness and tribocorrosion property of the deposits were studied. As the ZnSO 4 concentration increased from 0 g/L to 20 g/L, the morphology of deposits changed from fine-grained clusters to triangular based pyramids, and finally to granular grains. α phase, η phase and a mixture of α phase and η phase were identified in Fe-Zn coatings. And the microhardness of the deposits is influenced by the Zn content and grain size of Fe-Zn alloy. Furthermore, tribocorrosion behaviors of the deposits were investigated in NaCl solutions by electrochemical measures (potentiodynamic polarization, electrochemical current noise) with an abrasion-corrosion rig. Results of tribocorrosion tests showed that the primary form of the material loss was pure mechanical wear , except the deposit obtained at 20 g/L ZnSO 4 , whose mass loss due to corrosion-induced abrasion contributed most to its total material loss. The degradation mechanism of Fe-Zn deposits was also detailed in this paper. • Fe-Zn alloy was electrodeposited from an acid bath with improved stability. • The morphology of Fe-Zn deposits changed with the variation of phase structure. • Fe-Zn coating with 20% Zn provided the best combination of hardness and mass loss. • The wear mechanism of Fe-Zn deposits in silica slurry with NaCl was discussed.

Acoustic signatures and bubble entrainment mechanisms of a drop impacting a water surface with surfactant

The acoustics of a water drop impact on a bath of water and sodium dodecyl sulfate (SDS) is studied close to the irregular entrainment regime. In particular, acoustic events, corresponding to bubble vibration, are observed for several SDS concentrations. These acoustic events are induced by five different kinds of hydrodynamic events, including four different bubble entrainment mechanisms and one bubble excitation mechanism. These families of events appear to have their own acoustic signature. The different mechanisms are described in detail and typical signals belonging to these families are presented. Their main features are highlighted and linked to the hydrodynamics of the corresponding event.