Zn Ni Alloy Research Articles

Analysis of Corrosion Potential of Zn, Ni, and Zn-Ni Alloy Using Ab Initio Calculations Supported by Experimental Thermodynamics Data

The purpose of this study is to investigate the corrosion properties of Zn, Ni, and Zn - Ni alloy using density functional theory (DFT). DFT can assist in predicting the thermodynamic properties of challenging compounds such as metals, alloys, and transition metal oxides. In the present work, DFT is used to predict Zn, Ni, and Zn - Ni alloy phase diagram. The Hubbard correction (U) and dispersion correction (D) are used to minimize the inherent error associated with the DFT. We studied the crystal structure, electronic structures, and thermodynamic energies of Zn and Ni compounds using the generalized gradient approximation (GGA) density functional employing Perdew–Burke–Ernzerhof (PBE). We have developed the corresponding Pourbaix diagram of Zn, Ni, and their alloy to compare the performance of density functional theory with the experimental observations. The corrosion behavior of various alloys including Zn11Ni2,ZnNi,ZnNi3 are compared and discussed. This can be useful for predicting the corrosion-resistant properties of these alloys.

Physicochemical, Morphological and Anticorrosive Properties of Electrodeposited ZnNi Alloy Coating

Corrosion in its many forms is a major problem for many types of materials, extending from machining to manufacturing and daily use. In fact, it affects practically all engineering projects, from the biggest to the smallest: energy production, construction, transport, medical sector, electronics, etc. Consequently, corrosion generates both economic and environmental problems. To prevent corrosion and preserve materials' durability, several protection methods can be applied. These included protection by applying a coating on the metal surface. In this context, Zinc based alloy coatings have attracted much interesting scientific community because of their excellent mechanical and anti-corrosive properties. In the present work, ZnNi coatings were electrodeposited on steel substrates using a chloride bath containing ammonium salts. The effect of some experimental parameters, namely, potential and metal ion concentration ratio on the deposition kinetics of ZnNi system as well as on its physicochemical, morphological and anticorrosive properties has been investigated. For this purpose, an appropriate experimental work was performed by using both electrochemical (cyclic voltammetry, chronoamperometry, open circuit potential, potentiodynamic polarization) and nonelectrochemical (SEM-EDX) analysis methods. Based on the obtained results, it has been revealed that simultaneous codeposition of both elements Zn and Ni is possible in our experimental conditions. However, deposition kinetics exhibited a strong dependence on explored parameters. Also, morphological aspect and chemical composition of deposits are strongly influenced by metal ion concentration ratio. Investigation of corrosion behaviour confirms the protective effect of coatings acted as a sacrificial anode. Furthermore, increasing Ni content in the deposits induces a significant enhancement in corrosion resistance. Thus, Zn-Ni alloy coatings prepared from the Ni(II)-rich bath exhibited better corrosion resistance.

The characterisation of passivation and colouring of Zn-Ni electroplated 2024 aluminium alloy in the presence of Cu+

ABSTRACT The objective of this study is to develop a black chromate conversion coating (CCC) that meets the rigorous corrosion resistance and conductivity requirements of aerospace electrical connectors. The Zn-Ni alloy was successfully electrodeposited on the surface of 2024 aluminium alloy, and a black conversion coating was achieved through Cu+-based colouring. The conversion solution consisted of 10–14 g L−1 CrO3, 5–10 g L−1 NaCl, 10–13 g L−1 CuCl, and 15–25 g L−1 65-68%HNO3. The performance of the CCC was comprehensively evaluated through various techniques, including macro-observation, SEM, EDS, EIS, polarisation curves, and conductivity testing. The experimental results demonstrated that the prepared CCC exhibited a uniform black gloss, and that the conversion coating layer was primarily composed of Zn, Ni, O, Cr, and other elements. This coating layer significantly improved the impedance of the Zn-Ni alloy, reducing the corrosion current density to 5.35 × 10−5A cm−2, thus greatly enhancing its corrosion resistance. Furthermore, the resistance of the prepared CCC on a nearly hollow cylindrical electrical connector shell specimen with a height of approximately 3 cm and an inner diameter of approximately 1.5 cm was only 1.7 mΩ, which demonstrates excellent conductivity.

Multifunctional zinc-nickel alloy enabling high-performance aqueous zinc ion batteries

Aqueous zinc ion batteries are considered to be the new type of secondary batteries that have the potential to replace lithium-ion batteries as the most widely used in the future due to their green environment, high specific capacity and abundant zinc resources. However, due to the contact between the zinc anode and electrolyte, the generation of by-products and corrosion phenomena are not completely avoided, which can easily lead to problems such as short cycle life and poor electrochemical performance of the battery. In this study, uniform zinc-nickel alloy (ZnNi) was prepared by melting method. The element nickel has excellent corrosion resistance and is widely used to improve the corrosion resistance of metal alloys, so the introduction of nickel effectively enhances the corrosion resistance of ZnNi alloys. In addition, metallic nickel shows strong attraction to Zn2+, which can promote the uniform distribution and deposition of Zn2+ and inhibit the dendrites growth to prolong the battery life. Notably, the ZnNi-assembled symmetric cell exhibited excellent cycling performance compared with the Zn//Zn cell (100 h), with a cycle life of up to 1000 h at 2 mA cm−2. In addition, the capacity retention rate of the ZnNi//MnO2 full cell was still as high as 90.6 % after 1000 cycles. The preparation of the ZnNi alloy anode may provide a new idea for future alloying strategies.

Preparation and characterisation of black conversion coating of Cr(NO3)3–CoCl2–NiCl2 of Zn–Ni alloy electroplated on 2024 aluminium alloy surface

AbstractTo meet the application requirements of electronic connectors, a trivalent chromium process (TCP) conversion coating was prepared on the Zn–Ni alloy plating of 2024 aluminium alloy. The composition of the TCP solution was as follows: 45 g/L Cr(NO3)3, 14 g/L CoCl2, 1.3 g/L NiCl2, 10 g/L citric acid, 10 g/L succinic acid and 1 g/L sodium dodecyl sulphate. The properties of TCP were characterised by a range of techniques, including macroscopic observations, scanning electron microscope, energy‐dispersive X‐ray spectrometer, three‐dimensional (3D) morphometry, electrochemical impedance spectroscopy, polarisation curves and conductivity tests. The TCP prepared in this experiment exhibits a uniform black colour and bright appearance, predominantly composed of Zn, Ni, O, Cr and Co. The TCP enhances the impedance of Zn–Ni alloys, reduces the corrosion current to 1.99 × 10−5 A/cm2 and maintains a flatter surface 3D morphology and less surface roughness following electrochemical testing. It has better corrosion resistance. Following the preparation of the TCP on a suitably sized shell sample, the shell resistance was 1.2 mVDC with good electrical conductivity, which meets the requirements for electrical connector applications.

Effect of complexing agent on iron base zinc-nickel alloy coating

The influence of four complexing agents on corrosion resistance of Zinc-Nickel (Zn-Ni) alloy coating was investigated. The current density and plating time were determined by Hull and rectangular tank experiments. The effects of triethanolamine, potassium sodium tartrate, tetraethylenepentamine and sodium citrate on the properties of iron-based Zn-Ni alloy coatings were studied under the same electroplating process. The surface morphology, structure, elemental composition and corrosion resistance of Fe-base Zn-Ni alloy coatings with different complexing agents were analyzed. The surface and morphology of the coating were analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The anticorrosive properties of the coating were evaluated by electrochemical electrode and electrochemical impedance spectroscopy (EIS). The self-corrosion current density of triethanolamine is 2.927e-005A·cm−2, the rate of corrosion is minimal, rendering the material highly resistant to corrosion; the surface remains flat and exhibits a dense texture. The content of potassium, sodium, Zn and Ni in tartrate increased, thus reducing the corrosion resistance and flatness of the coating. The self-corrosion current density was 9.400e-005A·cm−2. The surface was rough and uneven, and there were a large number of large concave and convex defects. The complexing agent enhances the adhesion and corrosion resistance of the coating, improves the optical and mechanical properties of the coating, adjusts the durability and stability of the coating, increases the crystal packing density, increases the coating thickness, improves the adhesion with the substrate interface, and optimizes the uniformity of grain distribution. These factors are the key factors that determine the corrosion behavior of Zn-Ni coatings. In the process of electroplating, the addition of complexing agent can improve the quality of the coating, and suitable complexing agent can obtain smooth and bright coating at the same time, make the corrosion resistance of the coating higher.

Influence of electrodeposition-dealloying and silver nanoparticles on the electrochemical properties of nanoporous NiO films for supercapacitor

Nanoporous NiO films are prepared by electrochemical dealloying the Zn-Ni alloys electrodeposited on Ni substrates followed by self-oxidizing method. The electrodeposition-dealloying parameters are investigated. The optimal nanoporous NiO film exhibits a specific capacitance of 1212.0 F/g at 1 A/g. The capacitance retention rate can reach 71.9 % at 20 A/g. The improved electrochemical properties are attributed to the hierarchical porous structure, which can provide large specific surface areas with enough exposed active sites and enhance the mass transport. On the basis of this, nanoporous NiO films are decorated with Ag nanoparticles with an average size of 50.6 nm using photoreduction method. Owing to the good ohmic contact between Ag and NiO, the nanoporous NiO-Ag films possess an increased specific capacitance up to 3592.9 F/g three times higher than the nanoporous NiO film. The capacitance retention rate reaches 84.5 % at 20 A/g. An asymmetric supercapacitor NiO-Ag//AC exhibits an energy density of 116.88 Wh/kg at 1720 W/kg. An energy density of 85.41 Wh/kg is maintained at 36600 W/kg. These boosted electrochemical performances are mainly owing to the synergistic effects of unique hierarchical porous structure and high electronic conductivity. This study provides a new approach to high performance electrodes for supercapacitors.

Static recrystallization behavior and strengthening mechanism of a single-phase Cu–18Ni–17Zn alloy

The microstructural evolution and recrystallization behavior of a single-phase Cu–18Ni–17Zn alloy during annealing has been investigated. The strengthening effects of the solute atom concentration, grain size, and recrystallized volume fraction have also been studied. The results have shown that the difference in yield strengths for the fully recrystallized samples mainly depended on the grain boundary strengthening effect. This is attributed to a constant (∼41 MPa) solid-solution strengthening contribution in the completely recrystallized Cu–18Ni–17Zn alloy. When compared with pure copper, this alloy exhibited a high Hall-Petch constant (∼0.36 MPa m1/2), which is due to the higher grain boundary interface energy. A discontinuous recrystallization occurred in the alloy in the temperature range 400 °C–500 °C. Furthermore, the yield strength was linearly correlated to the recrystallized volume fraction in the partial recrystallized samples. Moreover, the addition of Ni and Zn increased the recrystallization temperature and slowed the recrystallization kinetics. The activation energy for the recrystallization was estimated as 92.6 ± 5.1 kJ/mol in the cold-rolled Cu–Ni–Zn alloy, which indicates that the grain boundary migration during recrystallization was mainly controlled by diffusion along the grain boundaries. In addition, the recrystallized grains preferentially nucleated at shear bands with high strain energies in the Cu–Ni–Zn alloy during annealing. As the regions of shear banding were completely consumed, new recrystallized nuclei formed at the grain corners. The limited number of nucleation sites resulted in a low Avrami exponent value that ranged from 0.41 to 0.61.

Effect of stray current on corrosion of concrete structure and improvement experiment of reinforcement coating

Concrete structures are often subjected to harsh environmental conditions, and problems such as corrosion will greatly limit their service life and safety. Stray current is one of the factors that can be easily ignored but seriously affect concrete structure. Therefore, the study of the influence of stray current on concrete structure is conducive to understanding the performance and corrosion mechanism of concrete structure, providing technical support for protecting concrete structure, and improving its service life and safety. In this experiment, the effect of stray current and chloride ion interaction on the corrosion of reinforced concrete structure was studied, and the protective effect of the coating on reinforced concrete was studied by using Zn-Ni alloy plating solution. Electrochemical workstation, silver nitrate spraying, scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and direct observation were used to simulate and compare the corrosion experiments under different current intensities. By analyzing the influence of 0.05 and 0.10 A stray currents on concrete corrosion, the chloride penetration resistance of concrete structures was evaluated, and blank control experiments were set for different current intensity and different energizing time. The corrosion resistance of the steel bar coated with Zn-Ni alloy is compared with the steel bar without changing the coating under the same corrosion conditions. The results show that the corrosion tendency of concrete structures will be further increased under the action of stray current and chloride ion coupling, and the corrosion reaction will be accelerated. In addition, at the same time, the higher the simulated current, the more serious the corrosion of concrete structure; Under the same simulated current, the longer the electrification time, the worse the resistance of concrete structure to chloride ion erosion. Moreover, the corrosion resistance of the steel bar coated with Zn-Ni alloy is better. In summary, this study concludes that the coupling of stray current and chloride ion causes damage to the corrosion of concrete structures, and the current intensity and energized time are proportional to the corrosion degree, and the modified Zn-Ni alloy coated steel bar has better corrosion resistance

Comparative study of zinc base alloy coatings: composition, microstructure, and corrosion resistance

The elemental composition, microstructure and corrosion resistance of three different zinc base alloy coatings (Zn–Ni alloy, Zn–Fe alloy and Zn–Co alloy) electrodeposited with the same complexing agent were studied by using a common zincate bath. The suitable current density is designed through experiments. Under the same current density, Zn–Ni alloy coating, Zn–Fe alloy coating and Zn–Co alloy coating are electrodeposited. The types and contents of microcomponent elements were analyzed by energy dispersive spectroscopy (EDS), the surface structure was analyzed by scanning electron microscopy (SEM), and the corrosion resistance was analyzed by electrochemical techniques (AC impedance, Tafel curve). The results show that the microstructure of Zn–Co and Zn–Fe alloy coatings is similar, the surface of the coatings is flat and the crystal distribution is uniform, but the grain of Zn–Co alloy coatings is obviously larger than that of Zn–Fe alloy coatings. In the electrochemical test part, the AC impedance of Zn–Co alloy coating is much higher than that of Zn–Ni alloy coating and Zn–Fe alloy coating, and the self-corrosion current density is lower than that of Zn–Ni alloy coating and Zn–Fe alloy coating, so it has the best corrosion resistance.

Effect of Nickel Co-Deposition Amount in Zn-Ni Alloy Plating on Hydrogen Embrittlement of High Strength Steel

Effect of Nickel Co-Deposition Amount in Zn-Ni Alloy Plating on Hydrogen Embrittlement of High Strength Steel

Fabrication of sustainable anti-icing metal surface with micro-nano composite concave angle structure by laser-electrodeposition-chemical method

Icing has adverse effects on human daily life and industrial production. The superhydrophobic surfaces have enormous potential for anti-icing applications because of the excellent water repellent effect. To enhance the anti-icing properties of metal surfaces, a hybrid method was employed, which combined laser processing, electrodeposition, and chemical soaking. This method was used to create a superhydrophobic surface with regular micro-nano composite concave corner structures on the surfaces of 7075 aluminum alloy. The morphology and wetting performance of samples under different current densities and deposition times were characterized. Under the current density of 40 mA/cm2 and the deposition time of 300 s, the hydrophobic performance of the prepared ZnNi alloy superhydrophobic coating was optimal. During the anti-frost testing, the prepared superhydrophobic surface only experienced water droplet aggregation, while frost never appeared. Compared to unprocessed surfaces, the prepared superhydrophobic surfaces showed a significant increase in anti-icing performance. Finally, the mechanism of the delayed icing on the surface of the prepared ZnNi alloy superhydrophobic coating was analyzed. This research provided a feasible approach for the manufacturing of superhydrophobic anti-icing surfaces.

Electrochemical Corrosion Resistance Evaluation of Zn–Ni Alloy Electroplating Process in Zincate Bath

Electrochemical Corrosion Resistance Evaluation of Zn–Ni Alloy Electroplating Process in Zincate Bath

Preparation of multifunctional protective coating on alloy surface by laser-electrodeposition additive-subtractive hybrid manufacturing

The preparation of multi-protective coatings is of great significance for improving the surface performance and prolonging the service life of parts. Here, a composite preparation method combining subtractive and additive manufacturing has been proposed to manufacture durable coatings with multiple protective capabilities. A special surface composed of a micro-nano structure and a zinc nickel composite coating was prepared through the clever combination of laser surface texturing technology and electrodeposition technology. The microstructure, surface chemical composition, and various protective properties of the prepared micro-nano structure and protective coating were mainly explored. Based on the experiment results, the Zn-Ni alloy coating successfully covered the aluminum alloy substrate. For the prepared superhydrophobic surface, the water drops contact angle was 151.5° while the sliding angle was 9°. The prepared surface exhibited excellent characteristics in reducing adhesion, mirror effect, water jet reflection, self-cleaning, anti-icing, corrosion prevention, and wear resistance. This study had positive significance in promoting the widespread application of metal based protective surfaces in the industrial field.

Planning and processing of Zn-Ni alloy thin film by electrodeposition

This work aims to improve and characterize a Zn-Ni alloy thin film from a sulfated bath by an electrochemical process. Experimental planning was applied using Minitab 19. For the selection of the best bath composition, a mixture design was applied. It was found that the best bath composition is [boric acid] = 0.1M, [saccharin] = 0.3 g/L, and [2-butene-1,4-diol] = 0.1 g/L. In order to optimize the best experimental conditions to have a better coating an application of the Box-Behnken design has been examined. Temperature, current density, and the ratio [Ni2+]/[Zn2+] are the various parameters. It was found that the best coating in terms of quality, corrosion resistance, brightness, and hardness was obtained under the following conditions: T= 30°C; i= 0.5A/dm2 and [Ni2+]/[Zn2+] = 0.53 with a theoretical response of 312.66 HV and an experimental response of 312.30 HV.These results were confirmed by morphological (SEM) and elemental (EDS) analyses.

Corrosion Resistance of Zn–Ni Alloy Films Electroplated in Alkaline Zincate Solutions Containing a Brightener

Corrosion Resistance of Zn–Ni Alloy Films Electroplated in Alkaline Zincate Solutions Containing a Brightener

Effects of Current Density and Bath Temperature on the Morphological and Anticorrosive Properties of Zn-Ni Alloys

The effect of current density and bath temperature in the electroplating process on resistance to corrosion of Zn-Ni alloys was evaluated in this work. The electrolytic bath consisted of nickel sulfate, zinc sulfate, sodium sulfate, boric acid, and sodium citrate at pH 7.0. The current density was varied in the range 20–80 mA/cm2 and the bath temperature in the range 30–60 °C. Increasing, independently, the current density or the bath temperature increased the nickel content in the obtained alloy, which affected the alloy microstructure, with a predominant γ phase and cauliflower-like morphology. The nickel content in the alloys was in the range 20–42%wt. A synergistic effect between the current density and bath temperature was observed from a design of experiments and response surface models. The maximum resistance to corrosion occurred for the alloy containing 42%wt. nickel. This alloy was obtained at upper levels of current density and bath temperature, presenting a corrosion potential of −0.789 V and polarization resistance of 4136 Ω.cm2.

Introduction of Heavy Micro‐Titanium‐Carbide Particles into Zn–Ni Coatings on Steel During In Situ Brush Electroplating

The heavy micro‐titanium‐carbide (TiC) particles are first introduced into brush‐electroplated Zn–Ni coating (TiC‐0 coating) by using some surfactants here. The effect of TiC concentration of brush‐electroplating solution on the properties of Zn–Ni–TiC coatings is investigated. It is found that the coating hardness and corrosion resistance are enhanced significantly due to the co‐deposition of TiC and an optimal coating with a thickness of 71 μm and adhesive strength of 37.2 MPa is obtained when TiC concentration was 40 (g L−1) (TiC‐40 coating). The pencil hardness of TiC‐0 and TiC‐40 is 2 H and 5 H, respectively. The corrosion resistance time to hot NH4NO3 solution (or inferred neutral salt spray) of TiC‐0 and TiC‐40 are 40 and 240 min (or 321 and 1995 h), respectively. Many pores appear on the coating due to the incomplete overlap of many batch layers. The TiC content is the factor dominating the coating hardness and corrosion resistance by changing the structure, contact angle, and pore diameter of coating, thereby changing the linear polar resistance Rp from potentiodynamic polarization curves, charge‐transfer resistance Rct or |Z|0.01 Hz, or polarization resistance from electrochemical impedance spectroscopy. The content of Zn–Ni alloy is the factor dominating the adhesive strength of Zn–Ni–TiC coating.

Surface Characterization, Mechanical Properties, and Corrosion Behavior of Zn-Ni Alloy Coated Steel Using Electroplating-Hot-Dip Galvanizing

In this study, the processing of zinc-nickel alloys with an electroplated nickel layer as the first layer followed by hot-dip galvanizing on plain carbon steel (St37) is investigated. The effect of the nickel layer and the effect of the immersion time on the alloy layers of the coating obtained by this method are studied. In addition, some properties of the obtained coating, such as the overall thickness, hardness, surface uniformity, coating adhesion strength, and corrosion resistance, were investigated using the optical microscope, scanning electron microscopy, energy dispersive x-ray spectrometer analysis, and potentiostat. The results show that the 16-min immersion time is the optimum galvanizing time at which an alloy with a nickel content of 0.11 wt% is formed and that the overall thickness of the galvanized sheet, especially the alloy layers, decreases compared to the pure zinc sheet. In addition, a more ductile, corrosion-resistant, and smoother surface is obtained.

Boosting electrocatalytic hydrazine oxidation at single-crystalline Ni nanosheets with embedded NiZn

Hydrazine oxidation reaction (HzOR) plays a crucial role in direct hydrazine fuel cells and holds promise for replacing the kinetics-sluggish oxygen evolution reaction in splitting water. While Ni–Zn alloys exhibit exceptional activity for HzOR, their synthesis under mild conditions remains a challenge. Herein, a Ni–Zn nanosheet catalyst with NiZn inclusion was prepared on Ni foam by controllable chemical etching together with ethylene glycol reduction. X-ray diffraction and transmission electron microscopy confirmed the single-crystalline nature and the presence of intermetallic NiZn. The strong interaction between Ni and ZnO, along with defects, facilitated the formation of this intermetallic compound. The Ni–Zn/Ni foam exhibits remarkable catalytic activity (214.3 ​mA ​cm−2 at 0.1 ​V) and durability (87.8 ​% retention after 24 ​h) towards hydrazine electrooxidation, thanks to the combined benefits of intermetallic NiZn, mesoporous nanosheets, microscopic defects, single-crystalline characteristics, and a coherent Ni–NiZn interface. This study provides a new method for designing highly active Ni–Zn electrocatalysts for HzOR.