Electrodeposited Ni-Fe Alloy Research Articles

Electrodeposited Ni–Fe alloy as a cost-effective material for harnessing hydrogen via the oxygen evolution and urea oxidation reactions

Electrochemical energy conversion for hydrogen production is a crucial method to address the global energy demand.

Electrodeposited Ni–Fe Alloy Foils with Changeable Nanostructures and Magnetic Properties for High Performance Wireless Charging

Electrodeposited Ni–Fe Alloy Foils with Changeable Nanostructures and Magnetic Properties for High Performance Wireless Charging

Fully Additive Fabrication of Electrically Anisotropic Multilayer Materials Based on Sequential Electrodeposition

MEMS-enabled multilayer composites, in which microfabrication is used to create micron-scale thickness layers within the volume of meso-scale thickness structures, can be exploited to create materials with highly anisotropic electromagnetic properties. Such materials have utility in both sensing and energy applications, including electrostatic and magnetic energy storage and conversion. A fabrication challenge in realizing these classes of materials lies in the size-scale disparity between the thickness of an individual layer and the desired thickness of the final anisotropic material. We demonstrate a fully additive sequential electrochemical deposition approach for such structures, which enables scalable composite volume while maintaining micron-scale individual layer thicknesses. Alternating metal and polymer layers, which exhibit very different electrical conductivities, are continuously electrodeposited in batch-scale. Individual layer thicknesses are controlled by deposition currents and times, while lateral extents are defined by lithographically defined molds. The fabrication process is illustrated using electrodeposited NiFe alloys and polypyrrole, and the anisotropy of electrical conductivity is assessed for potential use of these structures as magnetic cores for high frequency switching converters. Due to the relatively resistive polypyrrole layers, electrical anisotropy of lateral to vertical conductivity exceeding 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> was achieved. This approach offers a solution-based, microfabrication compatible, and manufacturable route to functional composite materials that exhibit high electrical anisotropies.

Electrodeposition of bulk nanocrystalline Ni–Fe–P alloys and their mechanical and soft magnetic properties

Electrodeposited Ni–Fe alloys are expected to have an improved mechanical strength because of their nanocrystalline structure. However, unsatisfactory grain refinement yields a higher coercivity compared with conventional permalloys, which is undesirable in soft magnetic materials. We report electrodeposited Ni–Fe–P alloys that combine the mechanical properties of nanocrystalline materials with soft magnetism that is achievable in coarse-grained permalloys. In Ni–Fe–P alloy electrodeposition, the connections between the bath composition and Fe and P contents of the samples were demonstrated. For Ni–Fe alloys, the introduction of a few percent of P led to a preferable microstructure that was composed of ~10-nm-diameter grains. Up to 2.0 at% P, the resultant Ni–Fe–P alloys achieved a tensile strength of 2.1 GPa, along with a plastic deformability. The electrodeposited alloys exhibited a saturation magnetic flux density of 1.1 T and a coercivity of 8.4 A/m. Our approach indicates that grain refinement by the P alloying can result in a lower coercivity, according to the law of grain size and coercivity.

Electrodeposition of Bulk Nanocrystalline Ni-Fe-P Alloys and Their Mechanical and Soft Magnetic Properties

Electrodeposited Ni-Fe alloys are expected to have an improved mechanical strength because of their nanocrystalline structure. However, unsatisfactory grain refinement yields a higher coercivity compared with conventional permalloys, which is undesirable in soft magnetic materials. We report electrodeposited Ni-Fe-P alloys that combine the mechanical properties of nanocrystalline materials with soft magnetism that is achievable in coarse-grained permalloys. Up to 2.0 at% P, the resultant Ni-Fe-P alloys achieved a tensile strength of 2.1 GPa, along with a plastic deformability. The electrodeposited alloys exhibited a saturation magnetic flux density of 1.1 T and a coercivity of 8.4 A/m. Our approach indicates that graine refinement by the P alloying can result in a lower coercivity, according to the law of the grain size and coercivity.

Mechanical and fracture behaviour of the three-scale hierarchy structure in As-deposited and annealed nanocrystalline electrodeposited Ni–Fe alloys

The growing interest in nanocrystalline (nc) materials is driven by their outstanding combination of mechanical and functional properties. Electrodeposited nc Ni–Fe alloys have received considerable attention, thanks to their unique strength and to their thermal and magnetic properties. However, the research on the relationship between microstructure, mechanical properties and fracture behaviour, under both As-deposited and annealed conditions, is still rather limited. In this paper, 48 wt% Fe electrodeposited nc Ni–Fe alloy foils were tested, by means of tensile and nanoindentation tests, under both As-deposited and annealed conditions (300–800 °C). High-resolution FESEM images revealed that the As-deposited microstructure consisted of an unforeseen, evident anisotropic nested three-scale hierarchy nc structure, namely from the nanocrystalline (~ 10 nm) to the sub-micron (up to 250 nm) scale, across a mesostructure (155–165 nm), here denoted as the characteristic grain structure. Such a nested nc grain structure of the electrodeposited nc Ni–Fe alloy, which resembles the one of a corncob (corncob-like structure), explained the unique anisotropic mechanical properties of the foils after nanoindentation, tensile and oblique-bending fracture tests. The mechanical properties (i.e. tensile strength, elongation, yield strength and hardness) of the foils annealed up to 320 °C were found to be improved, in comparison with the As-deposited counterparts, whereas those annealed above 320 °C were deteriorated.

Exceptional electrocatalytic oxygen evolution efficiency and stability from electrodeposited NiFe alloy on Ni foam

Highly efficient and low-cost electrocatalysts toward oxygen evolution reaction (OER) hold their promises in renewable energy technologies such as water splitting. Herein, we reported a fast electrodeposition of highly efficient NiFe alloy onto three-dimension nickel foam (NF). Benefiting from the hierarchical structure, NiFe/NF exhibits high OER efficiency with a low onset potential and a low overpotential (191 mV at 10 mA cm−2), which outperforms the commercial catalyst and most reported catalysts up-to-date. Also, it shows a remarkably low Tafel slope of 44.1 mV as well as a long-time stability that the potential increased less than 10 mV after 30000 s OER at 100 mA cm−2. NiFe/NF is expected to surpass the commercial catalyst to serve as a non-noble-metal-based electrocatalyst for OER practical application.

Water Splitting Electrodes Based on Nife Alloy Foil Produced By Roll-to-Roll Processing

With the rapid increase of global temperature and depletion of fossil fuels, developing sustainable energy resources is crucial nowadays. Among the various renewable energy source generation approaches, water splitting has attracted increasing attention for clean energy generation and efficient energy storage. Electrochemical production of hydrogen from solar electricity is also an attractive option for generating energy in the form of a hydrogen which could be used at a later stage for electricity. Over the past decades, despite of significant achievements have been obtained, the solar-to-hydrogen (STH) efficiency is still too low for practical applications. Low solar to hydrogen (STH) conversion efficiency is due to the suppressed water splitting reactions by high overpotential, especially oxygen evolution reaction. Due to relatively high overpotential than hydrogen evolution reaction(HER), the oxygen evolution reaction(OER) is a key reaction in water splitting. To overcome this problem, current studies are focused on development of efficient, abundant and inexpensive OER catalyst. The implementation of efficient electrocatalyst leads to decreased overpotentials, thereby making the whole process more energy-efficiently. Currently, the most efficient catalysts for water splitting are noble-metal catalysts such as Pt-group metals, Ru and Ir-based compounds. Unfortunately, the scarcity and high cost of noble metals seriously impede its large-scale applications in electrocatalytic water splitting. It is therefore highly attractive to explore earth-abundant materials to overcome this obstacle. In past decades, Ni has emerged as an important non-noble metal due to its catalytic power for water splitting and Ni-based compounds have been intensively studied as efficient OER and HER catalysts. Among the various type of Ni based materials, layered transition-metal alloy with Fe have attracted much attention of researchers because of their special redox character and good accessibility for the reaction species. Bimetallic electrocatalysts also have attracted increasing attention as a reliable approach to enhanced electrocatalytic activity for the HER. In the meantime, inspired by the abundant element Ni used in nature, various Ni-based catalysts have been designed to catalyze the conversion of H2O to H2 in commercial alkaline electrolyzers. Among these, Ni–Mo alloys are well-known non-precious-metal electrocatalysts for hydrogen production in alkaline electrolytes because of the increased intrinsic electrocatalytic caused by appropriate binding energy to hydrogen activity compared to pure Ni.Herein we report an approach to improve efficiency of water splitting electrodes based on flexible NiFe-based foil. Anodic oxidation method is applied to enhance the oxygen evolution activity of NiFe alloy foil. The anodized NiFe alloy foil exhibit significant higher activity than the corresponding Ni foam in base conditions. The anodic oxidation method generate NiFe oxide and hydroxide layers on NiFe alloy surface, act as electrocatalyst. Spontaneously, the anodic oxidation method widen the specific surface area of water splitting electrodes. Increased reaction sites and catalytic behavior of NiFe hydroxide is the reason of improved water splitting property. Because Ni based alloy like NiMo is remarkable hydrogen evolution catalyst, similar to noble metal, electrodeposition method is applied to enhance the hydrogen evolution activity of NiFe alloy foil. NiMo electrodeposited NiFe alloy foil exhibit highly enhanced activity than pure NiFe foil. Combining with 23% Si based solar cell using anodized NiFe alloy foil as anode and electrodeposited NiMo as cathode, PV-EC cell shows excellent STH properties around 18%.

Evolution of microstructure, mechanical and magnetic properties of electrodeposited 50% Ni-Fe alloy foil after thermal treatment

In order to expand the application of the electrodeposited Ni-Fe alloy foil, their mechanical and magnetic properties were studied after heat treatment. The development of grain growth during annealing was in-situ online investigated using a heating stage microscope, and the texture was analyzed via X-ray diffraction (XRD) and electron back-scattered diffraction (EBSD). The results indicated that abnormal grain growth usually occurred during annealing at 1000–1050 °C. The {111} oriented grains preferentially grew as the annealing temperature and holding time increased. The plasticities of the electrodeposited Ni-Fe alloy foils after heat treatment were better than those of the original samples. The excellent ductility was obtained without a loss in magnetic properties after annealing at 1100 °C for 6 h.

Effects of Annealing Temperature on the Microstructure and Mechanical Properties of Electrodeposited Ni-Fe Alloy Foils

AbstractThe plasticity, elastic modulus and thermal stability restrict the applications of electrodeposited nanocrystalline Ni-Fe alloy foils. To improve its mechanical properties, the electrodeposited Ni-Fe alloy foils were heat treated within the temperature 900–1,150 °C. The microstructure and texture of the samples were further analyzed with a combination of SEM, XRD and EBSD. The experimental results indicated that the electrodeposited Ni-Fe alloy foil had poor mechanical properties at about 1,000 °C, which was mainly attributed to the development of a mixed grain microstructure. At 900–950 °C, the plastic and elastic modulus were greatly improved, which were owed to the uniformed microstructure and the decrease of structure defects. At 1,050–1,150 °C, the degree of the mixed grain microstructure decreased, resulting in improved plasticity and higher elastic modulus. However, the strength of the foil obviously decreased, which was mainly associated with the increase of the average grain size.

Comparison of corrosion behavior between coarse grained and nanocrystalline Ni[sbnd]Fe alloys in chloride solutions and proton exchange membrane fuel cell environment by EIS, XPS and Raman spectra techniques

The corrosion resistance of coarse grained and nanocrystalline NiFe alloys in chloride solutions and proton exchange membrane fuel cell environment was investigated. The nanocrystalline NiFe alloys were obtained by electrodeposition, while coarse grained NiFe alloys were obtained by annealing. The results from electrochemical tests showed that coarse grained NiFe alloys had higher corrosion resistance than nanocrystalline samples in NaCl solution due to more compact passive films formed on the surface of coarse grained NiFe alloys. In addition, Raman spectra test showed that many nanocrystalline boundaries in electrodeposited NiFe alloys promoted the diffusion of nickel, which resulted in the formation of more nickel oxides and nickel hydroxides. However, the electrochemical study showed that coarse grained sample had lower corrosion resistance than nanocrystalline one in a typical proton exchange membrane fuel cell environment. The present study showed that nanocrystalline NiFe alloys were more suitable for the bipolar plates in proton exchange membrane fuel cell environment.

Effect of Plating Additives on Microstructure and Properties of Electrodeposited Ni-Fe Alloy

With the evolving technology, the frame mounted design of electronic components has increasingly become high-density, which leads to the electronic elements that are inevitably vulnerable to electromagnetic interference and then affect other electronic products’ functions. The solution is to use well conductive material that operates the shielding process. The material includes metals and conductive polymers which are common sources of the protective materials in dealing with the main conductive surface. Although this masking method has been widely recognized, several problems are still observed in practice, including the vulnerability to scaling, abrasion, corrosion and process load. In this study, we adopt Ni-Fe alloy film as the shielding material and manufacture it by electroplating. We intend to explore the effects of plating solution composition, plating parameter and plating additives on structural strength and magnetic properties of the Ni-Fe alloy film. In electroplating, plating additives play important roles. The results suggest that various additives lead to different crystalline orientations, grain sizes, and surface roughness. A correlation between the plated structure and the magnetic properties is studied. Additionally, anti-corrosion is improved by doping a few boron in the film. The ultimate goal of the study is to meet the requirements of electronic industry in manufacturing Ni-Fe alloy with high permeability and good corrosion resistance.

Effect of Plating Additives on Microstructure and Properties of Electrodeposited Ni-Fe Alloy Thin Film

With the evolving technology, the frame mounted design of electronic components has increasingly become high-density, which leads to the electronic elements that are inevitably vulnerable to electromagnetic interference and then affect other electronic products’ functions. The solution is to use well conductive material that operates the shielding process. The material includes metals and conductive polymers which are common sources of the protective materials in dealing with the main conductive surface. Although this masking method has been widely recognized, several problems are still observed in practice, including the vulnerability to scaling, abrasion, corrosion and process load. In this study, we adopt Fe-Ni alloy film as the shielding material and manufacture it by electroplating. We intend to explore the effectiveness of changing the plating bath composition, plating parameter and plating additives on structural strength and magnetic properties of the Fe-Ni alloy film. Different proportions of nickel and iron ion concentration and content of H3BO3 cause different proportions of electrodeposited elements in the film. And the higher content of nickel ion will have higher permeability. In magnetic electroplating, plating additives play an important role. The findings suggest that various additives lead to different crystalline orientations, grain sizes, surface roughness. A strong correlation is also shown between the observed structural changes and the changes in the magnetic properties, such as permeability. Additionally, anti-corrosion is a significant issue. We can improve the corrosion problem by doping little element such as Boron in the film, obtain the corrosion potential and corrosion current by Tafel analysis. The ultimate goal of the study is to meet the requirements of electronic industry in manufacturing high permeability and optimum corrosion resistance for shielding material Fe-Ni alloy film.

Structural and Magnetic Properties of Electrodeposited NiFe Alloy on Silicon Nanowires

Perpendicular Silicon nanowires (SiNWs), having 20 micrometer in length, were fabricated by metal assisted chemical etching of n-type Si(100) wafers in aqueous HF-solution. In a second step, NiFe films were electrodeposited onto theses SiNWs. The structure and magnetic properties of as deposited NiFe layers were studied by X ray diffraction (XRD) and vibrating sample magnetometer (VSM). From X-ray diffraction, the FCC NiFe structure was evidenced with a lattice constant, a, equal to 3.5270 (...)

Catalytic graphitization of PAN-based carbon fibers with electrodeposited Ni-Fe alloy

Ni-Fe alloy was electrodeposited on the surface of polyacrylonitrile (PAN)-based carbon fibers, and catalytic graphitization effect of the heat-treated carbon fibers was investigated by X-ray diffractometry and Raman spectra. It is found that Ni-Fe alloy exhibits significant catalytic effect on the graphitization of the carbon fibers at low temperatures. The degree of graphitization of the carbon fibers coated with Ni-Fe alloy (57.91% Fe, mass fraction) reaches 69.0% through heat treatment at 1 250 °C. However, the degree of graphitization of the carbon fibers without Ni-Fe alloy is only 30.1% after being heat-treated at 2 800 °C. The catalytic effect of Ni-Fe alloy on graphitization of carbon fibers is better than that of Ni or Fe at the same temperature, indicating that Ni and Fe elements have synergic catalytic function. Furthermore, Fe content in the Ni-Fe alloy also influences catalytic effect. The catalytic graphitization of Ni-Fe alloy follows the dissolution-precipitation mechanism.

Effects of saccharin on microstructure and property of electro-deposited Ni-Fe alloys

The Ni-Fe alloy coatings were prepared by electro-deposited method, and the effects of the saccharin content in the electrolytes on the microstructure of the coatings were studied by using X-ray diffractometry(XRD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results show that the saccharin content in the bath affects the plating rates and the current efficiency remarkably. As the saccharin content increases, the grain size of the Ni-Fe alloys decreases. The average grain size of the deposits varies from 13 nm to 10.8 nm as the saccharin content increases from 0 g/L to 8 g/L. Accordingly, the microhardness of the as-cold deformed samples increases from Hv 600 to Hv 656.

Heat Treatment for the Stabilization of Hydrogen and Vacancies in Electrodeposited Ni-Fe Alloy Films

In an effort to realize the long-term stability of the magnetostrictive property of electrodeposited Ni-Fe alloy films, heat treatments needed for eliminating the possible effect of hydrogen and hydrogen-induced vacancies have been investigated, mainly by use of thermal desorption spectroscopy. While metal-atom vacancies begin to move only above ∼500 K, hydrogen atoms can undergo slow motion and concomitant changes of state at room temperature, and are therefore believed to be a major cause of the long-term drift of the magnetism. Hydrogen atoms dissolved on regular interstitial sites can be completely removed by high-frequency pulse heating to 668 K, and those trapped by vacancies with relatively low binding energies by additional heat treatments to 453 K for over 1 h. This combination of heat treatments was found to reduce substantially the change of state of hydrogen during subsequent aging tests (383 K for 400 h), and proved to be effective for ensuring the long-term stability of magnetostrictive Ni-Fe film sensors.

Influence of substrate, pH and magnetic field onto composition and current efficiency of electrodeposited Ni–Fe alloys

The electrodeposition of nickel–iron alloys has been studied with different conditions of pH, substrate and magnetic field induction. All experimental conditions influence the current efficiency value and the alloy composition. For low current densities, alloys obtained at pH 3 present a smaller nickel percentage onto tin substrate compared to copper substrate. In the same time, the plating efficiency is improved onto tin electrode. On the other hand, if electrolyze is realized with magnetic field superimposition, the nickel percentage and the current efficiency are together reduced. For constant conditions of pH, substrate and magnetic induction, we observe that more the efficiency current is low, more the alloy composition is rich in nickel. All these effects relating to the plating efficiency and to the Ni–Fe alloy composition are elucidated using the hydrogen evolution reaction (HER).

ニッケル-鉄合金めっき膜中の水素および空孔の安定化熱処理

In an effort to realize the long-term stability of the magnetism of electrodeposited Ni-Fe alloy films, heat treatments needed for eliminating the possible effect of hydrogen and metal-atom vacancies have been investigated, mainly by use of thermal desorption spectroscopy. While metal-atom vacancies begin to move only above 480 K, hydrogen atoms can undergo slow motion and concomitant changes of states at room temperature, and are therefore believed to be a major cause of the long-term drift of the magnetism. Hydrogen atoms dissolved on regular interstitial sites can be completely removed by high-frequency pulse heating to 668 K, and those trapped by vacancies with relatively low binding energies can be removed by additional heat treatments at 453 K for over 1 h. The effectiveness of using this set of heat treatments to stabilize the performance of magnetostrictive Ni-Fe film sensors has been verified.

Magnetic and electrochemical studies on electrodeposited Ni-Fe alloys

Magnetic and electrochemical studies on electrodeposited Ni-Fe alloys