Ni Foil Research Articles

A Novel Method for Preparing Intermetallics/Superalloy Dissimilar Materials Using Current Sintering of Metallic Powders

Herein, a novel method is proposed to prepare the multimaterial composite component for aerospace applications using the current sintering. Two representative high‐temperature structural materials, the new potential intermetallic NiAl and the widely used Ni‐based superalloy K4202, have been employed to achieve the target. As shown by the results, a clean interface with almost no defects is successfully obtained in NiAl/K4202 alloy. Nevertheless, the existence of a continuous Cr(Mo) phase along the region leads to an insufficient bonding ability. To optimize the interfacial microstructure, a Ni foil is employed as the interlayer. The results indicate that the interlayer can hinder the intense diffusion of elements and prevent the abnormal growth of Cr(Mo) phases, which result in a considerable improvement of interfacial properties.

Interfacial microstructure and mechanical properties of diffusion bonded joints of additive manufactured 17-4 PH stainless steel and TC4 titanium alloy

A novel atomic diffusion additive manufactured 17-4 PH stainless steel and TC4 titanium alloy was successfully joined by vacuum diffusion bonding with Cu foil + Ni foil interlayers at the temperature range of 880°C–960 °C for 60 min with 2 MPa pressure. The interfacial microstructural evolution, interfacial diffusion of elements, and mechanical properties of joints were analyzed. The results indicated that the interfacial transition zone was composed of diffusion affect zone (DAZ) and interface reaction zone (IRZ). With Cu foil + Ni foil composite interlayers, reaction layers such as DAZ 1/IRZ 1/IRZ 2/DAZ 2 were formed in the transition zone, and the interface consisted of CuTi + CuTi2 eutectic phase, CuTi2, Ti (Cu, Ni) and α-Ti. Striped Ti (Cu, Ni) phases were surrounded by serrated CuTi2 phases, which contained Cu-poor, Ni poor areas, and the segregation of Ti atoms. The maximum microhardness of 693 HV0.1 and the maximum shear strength of 163 MPa were obtained at the bonding temperature of 920 °C and 960 °C, respectively.

The microstructure and mechanical properties of aluminum/steel welded joint with Ni foil interlayers by FSLW

Friction stir lap welding experiments between 6061 aluminum alloy plate and DP590 dual-phase steel plate were carried out. The effects of welding parameters and addition of Ni foil interlayers with different thickness on the microstructures and mechanical properties of the lap joints were investigated. The shear strength of the joint reached the maximum value of 6597 N and showed a mixed ductile-brittle fracture mode when the welding speed, the rotating speed and the thickness of the Ni foil intermediate layer were set to 100 mm/min, 900 rpm and 0.3 mm, respectively. A certain amount of beneficial plastic AlNi and FeNi3 intermetallic compounds are formed through the reaction of Al, Fe and Ni at the aluminum alloy/steel interface.

In-situ preparation of Zr-Al-Ni-Cu amorphous alloy by friction stirring using a tool consisting of multiple metal foils

Zr-Al-Ni-Cu amorphous alloy was prepared on an Al2O3 substrate by layering Zr, Al, Ni, and Cu foils, rolling them into a cylinder to fabricate a tool, and then pressing the tool onto the Al2O3 substrate while rotating the tool with a drilling machine. At the contact point between the multilayer metal foil tool and the Al2O3 substrate, Zr-Al-Ni-Cu amorphous alloy was formed by friction stir heating and mixing of the metal foils. The elastic modulus and hardness of the specimen were 173.0±7.9 and 11.7±0.7 GPa, respectively.

Improving the Microstructure and Mechanical Properties of Laser-Welded Al–Si-Coated 22MnB5/Galvanized Steel Joints Added by Nickel

To weaken the harm of Al–Si coating and increase the strength of welded joints, variable thicknesses of Ni foil (Ni, an austenitic formation element) were added to the lap laser welding Al–Si-coated 22MnB5 hot stamping steel/galvanized steel joints. The joints’ weld appearance, microstructure, and mechanical properties were explored. The weld altered from an X shape to a Y shape with an increased thickness of Ni foil. During welding, Al–Si coating was melted and diluted into the welding pool, forming δ-ferrite (a rich-Al phase with low toughness and strength) in the fusion zone (FZ) and fusion boundary (FB). This phase deteriorated the strength of the joints. After adding Ni, the amount and size of the δ-ferrite phase decreased. With a significant thickness of Ni foil, δ-ferrite disappeared. However, a new phase (fresh martensite (FM), which formed at low temperature and contained rich Ni) probably formed, except PM (previous martensite (PM), which formed at high temperature and contained little Ni or no Ni). The heat-affected zone (HAZ) on the side of 22MnB5 comprised a coarse martensite zone, refined martensite zone, martensite + ferrite zone, and tempered martensite zone from the FZ to the basic material. HAZ on the side of galvanized steel mainly contained ferrite and pearlite. After adding the Ni foil, the strength of the joint was greater than that without Ni. The maximum strength of the joint can be up to 679 MPa because of the disappearance of δ-ferrite. Meanwhile, the toughness of the joint increased. The fracture mode was from three mixed fractures (cleavage, quasi-cleavage, and dimple) to one fracture (dimple).

Role of Ni Content on Microstructure, Mechanical Property, and In‐Site Local Corrosion Behavior of Welded Joints Produced by Laser Welding of Dual‐Phase Steel

Herein, the effects of Ni content on the microstructure, microhardness, and in‐site local corrosion behavior of laser‐welded joints in dual‐phase steel are investigated. The experimental results indicate that the microstructure of the fusion zone (FZ) changes from martensite to austenite as the Ni content increases. The FZ hardnesses of the 0Ni (no Ni foil addition) and 50Ni (50 μm Ni foil) welded joints are higher than that of the 100Ni (100 μm Ni foil) welded joints because of the austenite in the 100Ni welded joint. The welded joint without Ni shows severe pitting corrosion (more than 15 pitting sites in each zone of the welded joint) at the tested corrosion time. However, when immersed in the corrosion solution, the welded joints with added Ni exhibit slight pitting corrosion (less than five pitting sites). The Ni addition inhibits the pitting corrosion of the welded joints of high‐strength dual‐phase steel.

A two-dimensional hybrid of NiO nanowalls and reduced graphene oxide for superior field emission

The sharp and 2D nanostructure of nickel oxide (NiO) was synthesized hydrothermally on the nickel(Ni) foil and studied for field emission application. Graphene oxide (GO) and reduced graphene (rGO) is also good field emitter due to their unique electrical properties and geometry. The 2D_NiO nanostructured substrate was coated with GO solution, and it form a hetero-structure. The structure, morphology, and elemental details of as-synthesized materials, as well as hybrid samples, were determined by using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS). The field emission study of the samples was studied for NiO nanostructures samples showed field emission response. The turn-on field and maximum currents are 7.5 V/μm and 4.9 mA/cm2; for graphene oxide coated Ni foil, Ni_GO sample, 14 V/μm, and the maximum current is 2.6 mA/cm2. With a coating of GO on the NiO nanostructured surface, the field emission response enhanced abruptly. In the hybrid sample, NiO_GO, the field emission response is enhanced abruptly, the turn-on the field and the maximum current are 5.7 V/μm and 15.5 mA/ cm2, respectively. The field emission response is substantially increased than that of the individual 2D nanostructure, which has shown a low field emission. The field emission response increased further, introducing rGO on the Nanostructured substrate. In the NiO_rGO sample, the turn-on field and the maximum currents are 4.4 V/μm and 39.6 mA/ cm2, respectively.

Analysis of laser welding on dissimilar materials with the influence of adding interlayer

The laser welding of dissimilar materials poses several challenges in practical applications, such as molten pool instability, the formation of intermetallic compounds (IMCs), and cracking caused by differential thermal stresses. In this study, we investigated the impact of incorporating a nickel (Ni) foil as an intermediate layer on lap joints of dissimilar materials (SS304 and Al6061) welded using the continuous laser welding (CLW) technique. The thermomechanical simulation accurately predicted the width and depth of SS304–Ni–Al6061 joints, with deviations of merely 3.92% and 19.04% from experimental results, respectively. Residual stress analysis revealed that the addition of a nickel foil reduced residual stress in the heat-affected zone (HAZ) and improved joint fatigue life. Furthermore, the incorporation of 0.1 and 0.2 mm Ni foils enhanced joint strength and effectively suppressed the formation of brittle intermetallic compounds, resulting in a remarkable maximum lap shear force of up to 1026 N. The simulation results for the shear load-displacement curve displayed excellent agreement with experimental data, with a deviation of only 6%. Notably, joints with the Ni foil demonstrated a greater ability to prevent crack formation caused by thermal expansion mismatch compared to joints without the Ni foil. The Ni interlayer served as a diffusion barrier and stress buffer, promoting a more uniform microstructure and reducing the likelihood of crack formation in bonded materials. Overall, this study comprehensively investigates the impact of incorporating a nickel interlayer on laser-welded lap joints of dissimilar materials. The findings offer valuable insights for practical applications, enabling improved joint strength, reliability, and crack resistance in laser welding dissimilar materials.

Ultra-high temperature brazing of C/C composite using pure Ni as filler based on eutectic reaction

To increase service temperature of brazed C/C-C/C joint, pure nickel was used as filler in ultra-high temperature brazing based on Ni-C eutectic reaction (1326 °C). The bond seam was composed of C-rich Ni(S.S.) matrix (FCC) and precipitating flake graphite; intimate interface and smaller contact angle (40°) confirmed good wettability; deep infiltration up to 120 μm occurred preferentially along perpendicular fibber bundle. As a result, 21.7 MPa shear strength was obtained. Fracture occurred within C/C side, rather than within bond seam or along initial interface. These results demonstrated that using pure Ni foil as filler even without strong/moderate carbide forming elements was feasible.

Two dimensional boron nitride growth on nickel foils by plasma assisted molecular beam epitaxy from elemental B and N sources

The growth of two dimensional sp2-bonded boron nitride (2D-BN) was studied in a plasma-assisted molecular beam epitaxy set-up, using independent boron and nitrogen sources. We studied the growth conditions on polycrystalline Ni foils: B and N respective fluxes, growth temperature and time, which are influencing the surface morphology, stoichiometry and the 2D-BN domain size. Using a B/N precursor flux ratio ≫1 yields films with incorporated boron largely in excess and intermixed with 2D-BN. On the contrary, precursor flux ratios from moderately B-rich to moderately N-rich leads to stoichiometric 2D-BN. The optimum growth temperature is found to be 900 °C, a temperature for which the crystallographic quality is improved compared to lower temperatures thanks to the increased adatom surface mobility although a partial sublimation of BN occurs. Increasing the growth time under the optimized settings shows that the growth does not occur in a layer-by-layer mode, but rather by stacking BN domains on top of each other with a rather slow lateral extension of the domains.

How the surface Cu layer affected the activity of Ni foil for alkaline hydrogen evolution

Synthesizing bimetallic nanomaterials, with noble metals as the surface layers and inert metals as the substrates, has been proven to be an effective way to reduce the use of noble metals with maintained catalytic activity. However, an atomic diffusion from the inert substrate to the surface during the long-term operation has been reported to significantly decrease the activity. In this work, a series of catalysis-inert Cu-coated Ni foil were fabricated through electrodeposition and their activities for alkaline hydrogen evolution were investigated. Notably, the Ni/Cu-60 sample showed a similar catalytic property with pure Ni foil and only a slight decrease in HER activity was observed. The X-ray photoelectron spectroscopy (XPS) results indicated a decreased electron concentration of Cu in Ni/Cu-60, and theoretical calculations further demonstrated the electron transfer between the Ni substrate and Cu layer. Our results reveal that a specific composition or structure of an inert metal layer might not significantly decrease the electrocatalytic activity of active metals. Moreover, there are more possibilities for the rational design of metal-based catalysts for electrocatalysis.

Flexible magnetoelectric sensor and nonvolatile memory based on magnetization-graded Ni/FSMA/PMN-PT multiferroic heterostructure

Flexible multiferroic heterostructures are promising to unveil technological developments in wearable magnetic field sensing, nonvolatile memory, soft robotics, and portable energy harvesters. Here, we report an enhanced and a zero-biased magnetoelectric (ME) effect in flexible, cost-effective, and room temperature sensitive Ni/FSMA/PMN-PT magnetization-graded ME heterostructure. Flexible Ni foil with −q (piezomagnetic coefficient) and the ferromagnetic shape memory alloy (FSMA; Ni-Mn-In) layer with +q offers the desired q-grading. The temperature-dependent dielectric behavior shows an anomaly in the martensite transformation regime of the FSMA layer. The Ni/FSMA/PMN-PT ME heterostructure exhibits noteworthy ME output of ∼3.7 V/cm Oe, significantly higher than Ni/PMN-PT (∼1 V/cm Oe). The q-grading-induced bending moment impedes the asymmetry-related flexural strain and strengthens the ME interaction. The zero-bias ME output of ∼0.4 V/cm Oe is ascribed to the interaction between q-grading-induced transverse magnetization and AC magnetic field. Ni/Ni-Mn-In/PMN-PT ME heterostructure displays excellent magnetic field sensing parameters: correlation coefficient, sensitivity, inaccuracy, and hysteresis of 0.99916, ∼0.74 mV/Oe, 1.5% full-scale output (FSO), and 1.8% FSO, respectively. The reversible and repeatable nonvolatile switching of the ME coefficient obtained with positive and negative electric fields is useful for next-generation memory devices. The flexible ME heterostructure shows no degradation in performance up to 1500 bending cycles. Such Ni/FSMA/PMN-PT based ME heterostructures are propitious for multifunctional flexible magnetic field sensors and nonvolatile memory applications.

Liquid Gallium-Assisted Patterned Growth of β-Ga2O3 Nanowires on Metallic Foils for Photocatalytic Dye Degradation

Herein, we report a facile and effective strategy for patterned growth of one-dimensional (1D) β-Ga2O3 nanowires on metallic substrates, based on the alloying of liquid gallium as a precursor. To demonstrate this method, the specific patterns are painted using gallium on a metallic foil through screen printing, which produces an intermetallic phase by alloying. The subsequent thermal treatment involving the sputtering Au serves as a catalyst to induce the formation of β-Ga2O3 nanowires on the foil. Notably, the gallium in the intermetallic phase maintains the in situ growth of nanowires. Such a growth process depends on the Au sputtering and temperature, which well follows a classical vapor–liquid–solid mechanism. Interestingly, benefiting from the unique physiochemical attributes of liquid gallium, the convenient alloying facilitates the synthesis of the nanowires at a moderately low temperature. This synthetic approach is also universal for a series of metallic substrates including Ag, Cu, Ni, and Co foils, and the production can be scaled up easily. Furthermore, as a model catalyst, the β-Ga2O3 nanowires grown on Ag foil (β-Ga2O3/Ag) display good photocatalytic performance and easy recovery in the degradation of dyes. The work provides an avenue to prepare patterned β-Ga2O3 nanowires based on liquid gallium.

Fabrication of SrWO4/PPy composite as electrode material for high-performance supercapacitors

The societal major concern of the moment is energy storage, energy production and global warming. Researchers are striving to create novel, highly efficient energy storage materials for developing faster, safer as well as more effective energy storage systems. One effective method to improve the electrochemical performance of supercapacitors (SCs) is the construction of highly efficient electro active materials, employing multivalent binary transition metal oxides (BTMOs) with electrical conducting polymers (CPs). For the first time, we report SrWO4/PPy composite synthesized by In-situ chemical polymerization route. The physio-chemical characteristics of the synthesized material was extensively examined with spectral and analytical techniques. SrWO4/PPy composite on Ni foil was fabricated as an alternate electrode material and was investigated for its capacitive behaviour. SrWO4/PPy electrode achieved a high specific capacitance of 747 Fg-1 at 5 mVs−1 and a remarkable cyclic stability of 93.8% even after 5000 cycles at 1 Ag-1. The notable electrochemical property of the electrode was attributed to its distinctive composite morphology, which is crucial in facilitating high conductivity, quick electron transfer, short ion diffusion distance and excellent active sites for enhanced electrochemical performance. The substantial capacitive behaviour can be attributed to the synergetic effect of SrWO4 and PPy. This work introduces platform to design efficient electrodes for the energy storage devices as well as for wearable electronics.

Electrophoretic Deposition and Characterization of Er-Doped Bi2O3 Cathode Barrier Coatings on Non-Conductive Ce0.8Sm0.2O1.9 Electrolyte Substrates

In this study, the formation of thin-film barrier coatings based on a highly conductive Bi1.60Er0.4O3 (EDB) solid electrolyte on supporting Ce0.8Sm0.2O1.9 (SDC) electrolyte substrates was implemented for the first time using electrophoretic deposition (EPD). The electrokinetic properties of EDB-based suspensions in a non-aqueous dispersion medium of isopropanol modified with small additions of polyethyleneimine (PEI, 0.26 g/L) and acetylacetone (0.15 g/L), as well as in a mixed isopropanol/acetylacetone (70/30 vol.%) medium, were studied. The dependences of the thickness of the EDB coatings on voltage and deposition time were obtained using deposition on a model Ni foil electrode. Preliminary synthesis of a conductive polypyrrole (PPy) polymer film was used to create surface conductivity on non-conductive SDC substrates. The efficiency of using a modified dispersion medium based on isopropanol to obtain a continuous EDB coating 12 μm thick, sintered at a temperature of 850 °C for 5 h, is shown. The microstructure and morphology of the surface of the EDB coating were studied. A Pt/SDC/EDB/Pt cell was used to characterize the coating’s conductivity. The EPD method is shown to be promising for the formation of barrier coatings based on doped bismuth oxide. The developed method can be used for creating cathode barrier layers in SOFC technology.

Large-scale vertical graphene on nickel foil as a binder-free electrode for high performance battery-like supercapacitor with an aqueous redox electrolyte

Due to the special three-dimensional structures and excellent physicochemical properties, vertical graphene (VG) has been extensively investigated as potential material for supercapacitors. However, achieving VG-based supercapacitors with high-energy density and high-power density is a still tremendous challenge. Here we attempt to synthesize large-scale VG films on flexible substrates and design a novel battery-like supercapacitor (BSCs) with the VG on Ni foil (VG@Ni) as a binder-free electrode operating in the KOH electrolyte with the redox additives of K3Fe(CN)6 and/or K4Fe(CN)6. The VG@Ni electrodes demonstrate an ultrahigh areal capacitance of 1453 mF cm−2 at 5 mA cm−2 in 1 M KOH electrolyte with adding 0.07 M K3Fe(CN)6 and 0.07 M K4Fe(CN)6, coulombic efficiency greater than 90%, and long-life cycling stability (capacitance retention is 99.3% after 20000 charge-discharge cycles). The BSCs, which are assembled with two identical VG@Ni electrodes, deliver the areal capacitance of 231 mF cm−2 with energy density of 32 μWh cm−2 and power density of 2498 μW cm−2 at 1 mA cm−2. These outstanding performances can be ascribed to the special feature and excellent properties of VG materials, high electronic conductivity of binder-free VG@Ni electrode, faradaic properties of redox electrolyte, and synergistic effects between the VG film and redox electrolyte.

Enhancement of Supercapacitor Performance of Electrochemically Grown Nickel Oxide by Graphene Oxide.

β-Ni(OH)2 and β-Ni(OH)2/graphene oxide (GO) were prepared on an Ni foil electrode using the electrochemical cyclic voltammetry formed in 0.5 M KOH solution. Several surface analyses such as XPS, XRD, and Raman spectroscopies were used to confirm the chemical structure of the prepared materials. The morphologies were determined using SEM and AFM. The addition of the graphene oxide layer showed a remarkable increase in the specific capacitance of the hybrid. Through the measurements, the specific capacitance values were 280 F g-1 and 110 F g-1 after and before adding 4 layers of GO, respectively. The supercapacitor displays high stability until 500 cycles are charged and discharged almost without a loss in its capacitance values.

Microstructure and Mechanical Properties of Zr‐4 Alloy and 316 Stainless Steel Diffusion Bonding Joint Using Nb/Ni Composite Interlayer

Diffusion bonding of Zr‐4 alloy and 316 stainless steel (SS) without and with the Nb/Ni composite interlayer has been performed. The maximum shear strength of the joint without interlayer is 131 MPa at 900 °C for 30 min under 10 MPa. The results show that the fracture occurs at the diffusion layer as a result of the limited mutual solubility between Zr and Fe and detrimental residual stress. Sound diffusion bonding joints without defects are obtained at lower bonding temperatures due to the addition of Nb/Ni interlayer, and the maximum shear strength is 380 MPa at 820 °C. The typical microstructure of the Zr‐4/Nb/Ni/316SS joint is Zr‐4/Zr(Nb)/Zr(Fe, Nb)2 /Zr(Nb)/Nb/Ni3Nb/Ni/(Fe, Cr, Ni)/316SS. The highest hardness value of the joint is 422 HV at the Ni3Nb phase, and cracks appear at the interface between Ni3Nb and the remaining Ni foil. The shear strength first increases and then drops as the Ni3Nb layer thickened. The peak residual stress of the joint reduces from 698 to 466 MPa due to the addition of the Nb/Ni composite interlayer. Finally, the growth kinetic model of the Ni3Nb layer is calculated, which provides a pathway for the regulation of joint properties.

Artificial Leaf for Solar‐Driven Ammonia Conversion at Milligram‐Scale Using Triple Junction III‐V Photoelectrode

Developing a green and energy-saving alternative to the traditional Haber-Bosch process for converting nitrogen into ammonia is urgently needed. Imitating from biological nitrogen fixation and photosynthesis processes, this work develops a monolithic artificial leaf based on triple junction (3J) InGaP/GaAs/Ge cell for solar-driven ammonia conversion under ambient conditions. A gold layer serves as the catalytic site for nitrogen fixation with photogenerated electrons. The Au/Ti/3J InGaP/GaAs/Ge photoelectrochemical (PEC) device achieves high ammonia production rates and Faradaic efficiencies in a two-electrode system without applying external potential. For example, at 0.2 sunlight intensity, the solar-to-ammonia (STA) conversion efficiency reaches 1.11% and the corresponding Faradaic efficiency is up to 28.9%. By integrating a Ni foil on the anode side for the oxygen evolution reaction (OER), the monolithic artificial leaf exhibits an ammonia production rate of 8.5µg cm-2 h at 1.5 sunlight intensity. Additionally, a 3× 3cm unassisted wireless PEC device is fabricated that produces 1.0039mg of ammonia in the 36-h durability test. Thus, the new artificial leaf can successfully and directly convert solar energy into chemical energy and generate useful products in an environmentally friendly approach.

Microstructure evolution and mechanical properties of the TiB2-TiC-SiC composite ceramic and Nb brazed joint

A high-density TiB2-TiC-SiC composite ceramic was prepared through hot pressing. The average flexural strength, fracture toughness, and hardness of the sintered composite ceramic were 486 MPa, 6.21 MPa·m1/2, and 20.6 GPa, respectively. Then, the active brazing of the composite ceramic and Nb using Ti and Ni foils was investigated. The results revealed that the TiNi-Nb eutectic structure was formed in the brazing seam by dissolving Nb. The interfacial reactions between the three components of the TiB2-TiC-SiC ceramic and the liquid TiNiNb filler were essential for obtaining a robust joint. During the brazing process, the TiB2 component reacted with active Ti in the liquid filler to form TiB, and then the TiB reacted with Nb to form NbB and Nb3B2 at the ceramic interface. Meanwhile, a thin (Ti, Nb)C reaction layer was generated near the TiC and SiC components. By increasing the brazing temperature from 1160 °C to 1220 °C, the width of the reaction zone neighboring the TiB2-TiC-SiC ceramic increased from 13 μm to 29 μm, resulting in a change in the shear strength of the brazed joints. When the joint was brazed at 1180 °C for 10 min, the shear strength of the joint reached a maximum value of 179 MPa. The crack was observed on the ceramic substrate close to the reaction zone.