Zn Ni Alloy Research Articles

Improvement in Mechanical Properties of Mild Steel by Magnetically Induced Electrodeposition of Ni-Zn Alloy

Improvement in Mechanical Properties of Mild Steel by Magnetically Induced Electrodeposition of Ni-Zn Alloy

Electrodeposition of ZnNi Alloys from Choline Chloride/Ethylene Glycol Deep Eutectic Solvent and Pure Ethylene Glycol for Corrosion Protection.

The present work follows the trend to develop non-aqueous electrolytes for the deposition of corrosion resistant ZnNi alloys. It investigates the use of the choline chloride/ethylene glycol (1:2 molar ratio) eutectic mixture and of pure ethylene glycol as solvents for ZnNi electroplating. The electrochemical behavior of Zn and Ni is investigated via cyclic voltammetry, and potentiostatic ZnNi deposition is performed. Ni content is found to be precisely tunable in the 10–20% wt range, which presents the highest industrial interest for corrosion protection. ZnNi coatings obtained are characterized from the morphological and phase composition point of view. Evidence of the formation of a metastable γ ZnNi phase is observed for both choline chloride/ethylene glycol and pure ethylene glycol. Finally, potentiodynamic corrosion tests are performed to assess their corrosion properties.

Electrodeposition of Zn-Ni Alloy from Alkaline Sulphate Bath Triethanolamine and Mercaptopyridine

Electrodeposition of Zn-Ni alloy from non-cyanide alkaline sulphate bath containing triethanolamine (TEA) and mercaptopyridine (MPY) under optimized plating conditions such as bath pH, temperature current density and metal ion ratio in the bath produced an alloy deposit with the desired composition of 10-15 %wt. of nickel, alloy of this composition showed good adhesion, high hardness pore free, smooth, uniform and finer grained. Deposition potentials of Zn-Ni alloy lie between the potentials of individual metals. Increase in temperature density decreased the nickel content in the alloy deposit, which with increase in temperature and thickness of the alloy deposit increased nickel content in the alloy deposit. Alloy deposition followed a regular type of co-deposition.

Charge-separated metal-couple-site in NiZn alloy catalysts towards furfural hydrodeoxygenation reaction

Catalytic conversion of biomass furfural (FAL) to high value-added products (e.g., 2-methylfuran, MF) has attracted considerable attention, in which control over catalytic selectivity plays a crucial issue. Herein, a series of heterogonous NiZn alloy supported on the mixed metal oxides (MMO) were synthesized derived from layered double hydroxides (LDHs) with various Ni/Zn ratio (3/1, 1/1 or 1/3). XRD, HRTEM and XAFS measurements confirm that with the increase of Zn content, the corresponding NiZn alloy transforms from α-NiZn (Ni3Zn1-MMO and Ni1Zn1-MMO) to β-NiZn (Ni1Zn3-MMO). Dramatically, the selectivity of MF displays an improvement from 12% to 95% along with this phase transformation process; and the MF yield reaches to 95% over Ni1Zn3-MMO sample. A combination study including XPS, CO-DRIFTS, in situ FT-IR and DFT calculation verifies that metallic Ni serves as active site, resulting in an effective suppression of side reactions (furan ring hydrogenation). Moreover, a charge-separated metal-couple-site (Niδ--Znδ+) is on the surface of Ni1Zn3-MMO originating from electron transfer between Ni and Zn. This active structure stabilizes a η2(C, O) adsorption configuration of intermediate, in which C atom is bonded to the Niδ− site and O atom is attached to the Znδ+ site. Then, this adsorption configuration facilitates the CO cleavage, giving rise to the production of MF. This work provides an efficient and cost-effective catalyst that can simultaneously inhibit CC hydrogenation and promote CO cleavage, which would be potentially used in catalytic conversion of biomass-derived platform molecules.

Electrodeposition of Single γ-phase Zn–Ni Alloy from Deep Eutectic Solvents using Metal Oxides as Precursors

The electrodeposition behavior of Zn–Ni alloy on a Cu electrode has been studied in the choline chloride-urea-ethylene glycol (ChCl-urea-EG) based deep eutectic solvent (DES). The nickel and zinc sources are introduced into the solvent by the dissolution of nickel oxide (NiO) and zinc oxide (ZnO), respectively. Cyclic voltammetry indicates that the electroreduction of Ni(II) or Zn(II) species in the DES is a diffusion-controlled process and the diffusion coefficient of Zn(II) species is an order of magnitude larger than that of Ni(II) species. Under the examined condition, the anomalous codeposition of Zn–Ni alloy is observed, which is different from normal codeposition of Zn–Ni alloy in similar DESs using metal chlorides as precursor. The deposition potential is found to play an important role in controlling the composition and surface morphology of the resultant Ni-Zn alloys. The phase structure of the deposits depends on the Ni content, and changes from a mixture of η-phase and γ-phase to single γ-phase with (411) plane orientation. A mechanism for this electrodeposition process has been proposed on the basis of the formation of complex ions [NiO·urea·Cl]−, [ZnO∙urea·Cl]− and [ChCl·O·urea]2− in ChCl-urea-EG-ZnO-NiO electrolyte during the electrodeposition, emphasizing that the metal oxides were dissolve in DES by forming metal complex ions, the cathodic reduction of metal complex ions generates complex ions [ChCl·O·urea]2− with alloys (NixZny), and [ChCl·O·urea]2− is oxidized to release O2 at anode.

Physico-Chemical Properties of Zn-Ni Alloy Deposits from an Acid Sulphate Bath Containing Ethanolamines

The composition, properties, structure and morphology of electrodeposited Zn-Ni alloy deposits obtained from an acid sulphate bath have been investigated. A bath having higher percentage of nickel (50%) produced an alloy deposit with low percentage of nickel (12%), the percentage of nickel in the alloy deposit increases with current density up to 40 A.dm-2, with further increase in current density, the percentage of nickel shows a downward trend, increase in temperature of the plating bath increases the percentage of nickel in the alloy deposit. The hardness of the alloy deposits increases with increase in nickel content in the alloy, the phase structure of alloy deposit shows the presence of α, η, δ and γ phases. The morphology of Zn-Ni alloy deposits shows uniform and finer grained structure.

Gamma-phase Zn-Ni alloy deposition by pulse-electroplating from a modified deep eutectic solution

This article describes the electroplating of ZnNi alloy from a modified deep eutectic solvent (DES), a mixture of choline chloride (ChCl) and ethylene glycol (EG) commonly known by its commercial name Ethaline. In this study the Ethaline was modified with propylene carbonate (PC) to decrease the solution viscosity. Boric acid was also used as an additive to improve surface finish and adhesion. The modifications were shown to increase the reduction rate of metal ions through improved mass transport and also to improve the quality of finish (morphology and interfacial adhesion) of the coating. We demonstrate that it is possible to produce dense, thick and adherent coatings of a γ-phase ZnNi alloy with 81–85% Zn on mild steel substrates using either potentiostatic deposition or controlled current pulse-plating techniques. Mild steel is a typical substrate for a sacrificial anti-corrosion coating used in many applications where the alloy serves to protect the steel from corrosion in harsh environments.

First-principles DFT insights into the adsorption of hydrazine on bimetallic β1-NiZn catalyst: Implications for direct hydrazine fuel cells

We present a systematic first-principles density functional theory study with dispersion corrections (DFT-D3) of hydrazine adsorption on the experimentally observed (111), (110) and (100) surfaces of the binary β1-NiZn alloy. A direct comparison has been drawn between the bimetallic and monometallic Ni and Zn counterparts to understand the synergistic effect of alloy formation. The hydrazine adsorption mechanism has been characterised through adsorption energies, Bader charges, the d-band centre model, and the coordination number of the active site - which is found to dictate the strength of the adsorbate–surface interaction. The bimetallic β1-NiZn nanocatalyst is found to exhibit higher activity towards adsorption and activation of hydrazine compared to the monometallic Ni and Zn counterparts. The Ni-sites of the bimetallic NiZn surfaces are found to be generally more reactive than Zn sites, which is suggested to be due to the higher d-band centre of −0.13 eV (closer to the Fermi level), forming higher energy anti-bonding states through NiN interactions. The observed synergistic effects derived from surface composition and electronic structure modification from Ni and Zn alloying should provide new possibilities for the rational design and development of low-cost bimetallic Ni-Zn alloy catalysts for direct hydrazine fuel cell (DHFC) applications.

An Experimental Study on Factors Affecting the Friction Coefficients in Electroplated Bolts

Electroplated bolts have been widely used in the automotive industry for many decades. In the present work, for the first time, the role of each layer of the bolt coating (i.e., electroplating, passivation layer, and topcoat layer) on the coefficient of friction of a bolted joint were experimentally and systematically investigated. The coefficient of total friction (μ tot), coefficient of friction between threads (μ th), and coefficient of friction between bearing surfaces (μb ) were calculated by a torque–tension testing system and compared under different experimental conditions. It was found that the μ th, μb , and μ tot on pure Zn plating was slightly different from that on Zn-Ni alloy plating; the black passivation layer had lower μ th, μb , and μ tot than the clear passivate when topcoats were applied; and the topcoat played a dominant role in reducing the μ tot. Other factors including washer material, nut plating, and heat treatment were also studied. Results showed that the aluminum washer gave a dramatically higher μb than the steel washer. The tested plating layers of Zn, Ni, and Zn-Ni alloy on the nut did not significantly affect the μ th. Tested bolts could withstand heat up to 182 °C for 1 h. Higher temperature or longer heating time increased μ th, μb , and μ tot. These findings will increase the understanding of the factors that affect the friction coefficients in electroplated bolts and will help to better design bolted joints.

INVESTIGATION OF SOME PROPERTIES OF ZINC-NICKEL ALLOY PLATING WITH TRIETHANOLAMINE, p-AMINOBENZENESULFONIC ACID, AND GELATINE

Anticorrosion requirements for the metallurgy, automotive, and aeronautical industries have increased in recent years, for which alternative plating chemicals must be developed. This study focuses on obtaining a Zn-Ni alloy plating with higher corrosion resistance and brightness. For this purpose, tetraethylenepentaamine as complexing agent, triethanolamine as the surfactant, and gelatin and [Formula: see text]-aminobenzenesulfonic acid as brightening agents for the plating were selected and their optimal concentrations were determined for applications. The optimal Zn-Ni ratio and plating thickness were analyzed using an X-ray Dal device. Improved plating performance of the Zn-Ni alloys was achieved with a Zn-Ni alloy containing 12–14% Ni.

Progress in Electrodeposition of Zinc and Zinc Nickel Alloys Using Ionic Liquids

Zinc (Zn) and zinc–nickel (Zn–Ni) electrodeposition has been widely used in many industries, such as automotive and aerospace, for corrosion protection of steel components owing to their excellent corrosion resistance. Conventional zinc and zinc–nickel electrodeposition is performed in different types of aqueous baths (acid and alkaline). Such electrolytes suffer from certain drawbacks such as hydrogen gas evolution, low coulombic efficiencies, and environmental toxicity. Electrodeposition of Zn and Zn–Ni alloys from ionic liquids has gained significant attention in aerospace and automotive sectors owing to the different environments they provide for electrodeposition. This paper reviews the progress in deposition of zinc and zinc-nickel alloys in non-aqueous systems, especially ionic liquids. In addition, the challenges and technological developments associated with the Zn and Zn–Ni deposition on different substrates and the factors that need to be considered while electroplating at an industrial scale are discussed.

Influence of the microstructure of Zn–Ni coatings on hydrogen effusion characteristics

This study reports about the influence of the microstructure of electroplated Zn–Ni alloy coatings, especially the extent and characteristic of existing microcracks within, on hydrogen effusion characteristics at room temperature (RT) and 200 °C. For comparison, the behavior of an electroplated Zn coating was also investigated. The microstructures of the Zn and Zn–Ni coatings were examined by means of scanning electron microscope (SEM) and optical microscope (OM). These results were correlated with the hydrogen effusion profiles, which were determined by using a carrier gas hot extraction (CGHE) technique. In addition, a silver decoration method was applied to visualize the hydrogen effusion paths within the coatings. First both Zn–Ni electroplating processes exhibit less hydrogen absorption compared to Zn. In addition the microstructure of the Zn–Ni coatings, especially the characteristic and magnitude of the microcracks, significantly influences the hydrogen effusion characteristics. By using the silver decoration method according to (Schober in MTA 14:2440-2442, 1983) it could be proofed that for Zn–Ni hydrogen primary effuses along the microcracks and the interfaces of pustules within the coating. But the microcracks seem to promote the hydrogen effusion much more than the interfaces of the pustules.

Corrosion behaviour of Zn-Ni alloy and Zn-Ni-nano-TiO2 composite coatings electrodeposited from ammonium citrate baths

Electrochemical and corrosion behaviour analysis of Zn-Ni alloy and Zn-Ni-nanoTiO2 composite coatings electrodeposited on steel from ammonium citrate containing bath was performed. The complexation of zinc and nickel ions in citrate stabilized the electroplating bath. The electrochemical behaviour of samples showed that Zn-Ni alloy with the incorporation of 0.003 mol/l of titania (TiO2) nanoparticles exhibited noble corrosion potential (Ecorr) and decreasing corrosion current (Icorr). This leads to increase impedance modulus with a more compact and durable uniform coating of 25.84 nm grain size. The surface characterization and crystalline phase texture of the coatings were investigated by scanning electron microscopy (SEM) integrated with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The topographical structure of the coating was analyzed by atomic force microscopy (AFM). The chemical composition result showed that the Zn-Ni+0.003TiO2 coating electrodeposited from a citrate bath in various immersion tests reduced dezincification in the coating. The presence of higher intensity of the γ-phases (γ-NiZn3) (815) and γ-Ni2Zn11 (330) (631) plane orientation and β-Ti phase provide better corrosion resistance performance of the coating. The most significant corrosion products for Zn-Ni alloy electroplating are simonkolleite, hydrozincite, zincite, and wulfingite.

Anticorrosive Zn–Ni alloys: An alternative for the treatment of electroplating industry wastewater

Substrate protection coatings are widely applied in the industry. Zn–Ni alloys have less potential for corrosion, thus preserving the steel substrate by corroding first. In this sense, this study used nickel-rich electroplating industry wastewater to produce Zn–Ni alloys under different conditions, analyzing the zinc sulfate concentration, electric current density, and rotating cathode in the deposition. The nickel removal kinetics showed a reversible and first-order behavior. The alloys with a composition of 2 wt.% nickel, according to energy-dispersive X-ray spectroscopy analysis, were more anti-corrosive with polarization resistance of 1276.7 Ω cm2, than the alloys containing 5 wt.% nickel. Electrochemical impedance spectroscopy proved that alloys containing 2 wt.% nickel were more resistant to corrosion and indicated the formation of a porous oxide layer. Besides, the micrographs of the alloys containing 2 wt.% nickel showed homogeneity without cracks and nodular grains, unlike the alloys with 5 wt.% nickel, which had cracks and were heterogeneous. The X-ray diffraction diffractograms showed different structures according to the amount of Ni. Thus, the deposition of metals from wastewater is an alternative to conventional treatments and avoids the use of synthetic baths.

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.

Electrodeposition of ZnNi Alloys from Ethylene Glycol for Corrosion Protection

Zn rich ZnNi alloys electrodeposition have recently attracted the attention of researchers due to their interesting corrosion properties [1]. In particular, alloys containing Ni in the 15 - 25 % range find application in a number of industrial fields, like automotive and constructions. ZnNi is normally electrodeposited from aqueous solutions, in which plating takes place following a typical anomalous mechanism [2]. In the last few years, however, new deposition approaches have been attempted to improve ZnNi plating performances. Specifically, III generation deep eutectic solvents comprising choline chloride have been tested [3].The present work investigates the use of non-aqueous ethylene glycol based electrolytes for the deposition of Zn rich ZnNi alloys. The use of ethylene glycol as solvent introduces many advantages with respect to aqueous solutions: low oxygen contamination, high deposits purity and no pH dependance [4]. ZnNi codeposition was studied employing cyclic voltammetry and layers were deposited under potentiostatic control. Deposition potential was varied and its influence on final composition and morphology was determined. Addition of an additive (NH4Cl) to enhance surface morphology was attempted as well [3]. Phase composition was investigated using XRD to determine the possible presence of a metastable γ-ZnNi phase, which has already been observed in the case of ZnNi plated from alkaline aqueous solution [5]. Finally, corrosion behavior of layers obtained from ethylene glycol was assessed and compared with equivalent coatings deposited from commercial aqueous solutions.[1] M. Gavrila et al.; Surface and Coatings Technology, 123 (2-3), 164-172 (2000)[2] G. Roventi et al.; Journal of Applied Electrochemistry 30 (2), 173–179 (2000)[3] S Fashu et al.; Transactions of Nonferrous Metals Society of China 25 (6), 2054-2064 (2015)[4] G. Panzeri et al.; Electrochimica Acta 271 (1), 576-581 (2018)[5] S. Ieffa et al.; Transactions of the IMF 94, 321-324 (2014)

Effect of Minor Addition of Ni on the Microstructure and Properties of Zn-Based High-Temperature Solder

Lead-based solders are widely used for making interconnections between electronic chips and a circuit board that is expected to perform at high temperatures. The substitution of traditional lead-bearing solders is one of the key challenges to electronic industries in the current drive for eco-friendly manufacturing. In the present study, a minor amount of Ni is alloyed with Zn to investigate the effect of Ni on the microstructure and the thermal, mechanical and electrical properties of the newly developed solder. The microstructures of the Ni-Zn solder alloys are composed of β-Zn and Ni-Zn intermetallics (γ-phase). The appearance of a γ-phase Ni-Zn intermetallic (NiZn5) instead of a δ-phase intermetallic in a eutectic structure, grain boundary particles and an irregular second phase is discussed in detail. Addition of Ni results in enhanced mechanical properties, keeping the electrical properties unchanged. The suitability of Ni-Zn alloy as high-temperature solder is evaluated in comparison with traditional Pb-Sn solders and other Zn-based alloys.

Microstructure and phase transition kinetics of Mg–Ni–Zn alloy phase change thermal storage materials

Metal and alloy heat storage materials are popular in energy storage fields due to their excellent thermal conductivity and high latent heat value. In this research, by changing the ratio to optimize Mg–Ni–Zn alloys, we study the microstructure and thermal properties of alloys with different composition ratios, and the relationship between alloy composition and properties was deeply analyzed. Besides, we also study the thermal analysis kinetics of the alloys. The results show that the Mg–Ni–Zn heat storage alloy mainly contains α-Mg, Mg2Ni, Mg7Zn3, MgZn2 and its eutectic structure. The increase of Zn content is beneficial to the increase of phase transition temperature and phase transition latent heat value, among which the maximum latent heat value of Mg–13%Ni–37%Zn alloy can reach 165 J g−1. In this research, a new type of ternary alloy heat storage material Mg–16%Ni–24%Zn alloy is proposed, and the activation energy of Mg–16%Ni–24%Zn alloy is 1014.99 kJ mol−1 by Coats-Redfern integral equation and extrapolation method. The mechanism function is the Mampel Power rule, and the integral form is G(α)=α32, which is a reference for subsequent researchers.

AISI 4140 Steel Fatigue Performance: Cd Replacement by Electroplated Zn-Ni Alloy Coating

The fatigue behavior of electrodeposited Zn-Ni alloy coating was investigated for its suitability to replace Cd coatings in AISI 4140 steel studs applied in oil and gas industries due to environmental and human health considerations. Axial fatigue tests were carried out at room temperature and statistically analyzed through two-parameter Weibull distribution. The coatings characterization included chemical composition and corrosion resistance analysis through energy-dispersive spectroscopy and salt spray tests, respectively. Furthermore, the fracture surfaces were observed using scanning electron microscopy, and the stress gradient in studs was obtained through finite element analysis. The experimental results showed that the notch sensibility was higher for high-cycle fatigue regime, varying from 0.20 to 0.61 for 104 and 105 cycles, respectively. The stress concentration effect influenced the fatigue life of the component, especially for low-stress levels, decreasing the fatigue strength in about 9% for 104 cycles and more than 20% for 105 cycles. The experimental fatigue data showed an increase in axial fatigue strength of about 8% for 105 cycles for electrodeposited Zn-Ni coating specimens, indicating feasibility with respect to fatigue behavior of the substitution of electrodeposited Cd for a Zn-Ni alloy.

Effect of Al on phase evolution in Prior-Ni coated galvanized steel: Thermodynamic and kinetic assessment

Coating of advanced high strength steel and ultra-high strength steel is a burning issue due to the problem of surface oxidation of alloying elements and liquid metal induced embrittlement (LMIE). In last decade, prior coating of Ni before galvanizing has gained much interest as it has the potential to suppress the surface oxidation of advanced high strength steel with added benefits. Recently, the galvanized ultra-high strength steel with a prior-Ni coating also has been proved as a solution for hot stamping application. It has been observed that prior-Ni reacts with Zn at the stage of galvanizing and forms different Ni–Zn alloy phases with high melting temperatures and resist the LMIE at the time of hot stamping. Al is one of the most important alloying element in commercial galvanizing bath. However, effect of Al on the Ni–Zn phase formation in such coating has not been researched in detail. In the present study, phase formation in prior-Ni coated galvanized steel in the presence of Al in Zn bath has been thoroughly investigated. The influence of Al on the Ni–Zn phase formation has been assessed by thermodynamic and kinetic calculation and then validated by experiments. Al3Ni2 with dissolved Zn precipitated in the Zn overlay and of Ni–Zn alloy phases such as NiZn8 and gamma phase formed on prior-Ni layer in a Zn–Al bath up to 0.01 mass fraction of Al. However, Ni–Zn alloy phases such as NiZn8 and gamma phases were absent in coating achieved by Zn–Al bath above 0.01 mass fraction of Al. Instead a thin compact layer consisting high amount of Ni, Al and Zn formed on prior-Ni layer and hindered the formation of Ni–Zn alloy phase in coating. The mechanism of the phase formation in the prior-Ni coated galvanized steel in presence of Al has been described with the help dissolution, phase fraction, driving force calculations and experimental observations.