Nickel Thickness Research Articles

Enhancing hydrogen separation efficiency: Insights from the permeability study of nickel-based composite membranes

This research aims to validate the capability of composite nickel-based membranes in separating hydrogen and to examine how multi-layer deposits influence the density of the nickel film. The study evaluated the hydrogen permselectivity of the membranes for both single gases (H2, N2) and binary mixtures over a temperature range from 25 °C to 700 °C. The findings revealed that the thickness of the nickel layer (ranging from 2 μm to 37 μm) and its adhesion to the support material affected the hydrogen transport through the films. Increasing the number of electroless plating treatments and the nickel thickness on γ-alumina and α-alumina tubular supports resulted in decreased hydrogen permeance but improved hydrogen selectivity. This was attributed to the enhanced recovery of the γ-alumina support and efficient filling of α-alumina support pores, depending on the membrane type. The study identified multiple mechanisms contributing to hydrogen transport, including surface diffusion, Knudsen diffusion at lower temperatures (<300 °C), and activated diffusion processes at higher temperatures (>300 °C). At 700 °C, for a Ni/0.8 μm-α-Al2O3 membrane with a 37 μm nickel film, the hydrogen permeance for single gases was 5.8 × 10−8 mol/m2 s Pa (189 GPU: gas permeance unit) with an ideal selectivity of 199 towards N2. It was 7.3 × 10−8 mol/m2 s Pa (238 GPU) for gas mixtures with an H2/N2 separation factor of 148. These results suggest that these membranes are particularly effective at high temperatures, emphasizing their potential for hydrogen separation applications and positioning them as promising materials for further development in this field.

Influence of Pt Ultrathin Interlayers on Magnetic Anisotropy in Ni/NiO Multilayers

Perpendicular magnetic anisotropy at transition metal/oxide interfaces plays a significant role in technological applications such as magnetic storage and spintronics. In this study, we investigate the effects of thermal annealing and Pt ultrathin interlayers on the magnetic anisotropy in Ni/NiO multilayers. Ni/NiO/Pt multilayers were fabricated via radiofrequency magnetron sputtering and natural oxidation. The static magnetic properties of the samples were studied using temperature-dependent SQUID magnetometry. We focus on a sample with a Nickel thickness of 6.7 nm in each multilayer period. This multilayer in Ni/NiO form showed the maximum enhancement of perpendicular magnetic anisotropy after mild thermal annealing in past work. In this work, we study the effects of ultrathin Pt interlayers on the magnetic properties of such a Ni/NiO multilayer before and after annealing. We have observed a further increase in perpendicular magnetic anisotropy, and we study the temperature-dependent magnetic properties of this system, which combines the favorable magnetic properties of Ni/Pt and Ni/NiO multilayers.

Effect of Brazing Filler Metals and Welding Parameters on Laser Welding-Brazing Joints of WC-Co to S1045

Laser welding-brazing was used to join cemented carbide WC-Co and steel dissimilar materials. In this study, high-speed welding was adopted. The effect of welding parameters and brazing filler metals on the macrostructure, elemental diffusion, micro hardness and thermomechanical behavior was analyzed using optical metallography, scanning electron microscopy, electron probe micro-analysis, hardness test, and finite element method (FEM) based on thermo-elastic-plastic analysis. The experimental results show that increasing laser power is helpful to the increase of maximum welding speed. However, FEM also shows that increased welding speed leads to residual stress concentration, especial in the vicinity of jig. It is still a challenge to optimize laser power welding speed for a given brazing filler metal. The results show: when using pure copper, silver and nickel (thickness is less than 0.5 mm) as brazing filler metal, the combination, laser power of 1.2 kW and welding speed at 0.1 m/s, leads to complete penetration with good weld formation. However, when using Cu/Invar/Ni as brazing filler metal, laser power should increase to 1.7 kW if we still using a higher welding speed (0.1 m/s). Although a trial of high speed welding in laser welding-brazing exhibits feasibility, as-welded joints still have much more brittle risks due to the higher residual stresses.

Inverse Magnetostrictive Effect in Ni&lt;SUB&gt;x&lt;/SUB&gt;Fe&lt;SUB&gt;1-x&lt;/SUB&gt; (1≤ x ≤0.8) Thin Films Deposited on a Polypropylene Substrate

The magnetostriction effect is a unique phenomenon observed in magnetic materials due to applied stress. The permeability μ of the magnetic material increases or decreases depending on the sign of the magnetostriction coefficient λ based on the direction of the applied stress. For example, nickel has a negative λ, whereas iron has a positive λ for the same tensile (+) or compressive (-) stresses. However, the magnetostriction effect is reported to disturb the functionality of some spintronic applications, such as magnetic sensors and actuators, under the influence of an external magnetic field. Therefore, suppression of the magnetostriction effect is a challenge in developing flexible spintronic devices. In this study, the magnetostriction effect of the NiSUBx/SUBFeSUB1-x/SUB thin films was investigated under different stress conditions. The composition of the thin film was manipulated by varying the deposition thickness of nickel and NiSUB8/SUBFe₂ targets using a co-sputtering system. Magnetization reversal behaviors of the NiSUBx/SUBFeSUB1-x/SUB thin films were observed under the influence of an external magnetic field by using a vibrating sample magnetometer (VSM), before and after the application of bending stress. The negative magnetostriction effect of nickel was decreased by increasing the iron composition in the thin film, owing to the opposite sign of the magnetostriction coefficient. Finally, an extremely low magnetostriction was achieved at x = 0.8. The results of this study suggest that the magnetostriction effect can be controlled by varying the composition of the thin films and a sufficiently small magnetostriction effect can be observed at the permalloy composition between nickel and iron.

Synthesis and Characterization of Novel Nickel Coated Carbon Fibre Rod Reinforced Aluminium Metal Matrix Composite Material for using in Automobile Application

A carbon fibre (CF) in the form of a rod (continuous fibre) was used as reinforcement due to its superior strength and modulus properties. Carbon fibre rod reinforced aluminium 6061 alloy metal matrix composite material was synthesized using the stir casting liquid metallurgy route. Aluminium based metal matrix composite materials are light in weight. Very few researchers were worked on carbon fibre rod reinforced metal matrix composites (MMC). Electroless nickel deposition on carbon fibre rods (2mm and 3mm diameter) were carried out for improvement in wettability. On carbon fibre rods, the effectiveness of electroless nickel coating was validated using SEM (scanning electron microscopy) and EDAX (Energy Dispersive X-Ray Spectroscopy) analysis. A further coating thickness of nickel was improved using nickel electroplating. In a cast iron mould, nickel-coated carbon fibre rods were arranged in a circular pattern. Completely degassed molten aluminium 6061 alloy was poured in cast iron mould at 600-700 °C. The enhancement in Tribological and mechanical properties is always a prerequisite for technological advancement in automobile sector. From synthesized composites (11.11% Vol. CF and 25% Vol. CF reinforcement) specimen were prepared for density tests, bulk and microhardness tests, friction and wear tests. Synthesized composite has low density, increased bulk and microhardness, low coefficient of friction and reduced wear rate in comparison with aluminium 6061 alloy. Keywords: Carbon Fibre (CF) rod, MMC, Nickel coating, Casting, Mechanical, Tribological

Electrochemical method for obtaining of composite graphite powder

An electrochemical method for producing a composite graphite powder by depositing nickel, copper and Cu—Ni coatings on graphite powder grade GL-1 is proposed, which ensures the production of a clad powder material. An installation, a technological scheme was developed, and a cyclic method of electrochemical metallization of graphite was proposed, which makes it possible to obtain a composite graphite powder of a given chemical composition. An electrochemical method for producing a composite graphite powder by depositing nickel, copper and Cu-Ni coatings on graphite powder grade GL-1 is proposed, which ensures the production of a clad powder material. An installation, a technological scheme was developed, and a cyclic method of electrochemical metallization of graphite was proposed, which makes it possible to obtain a composite graphite powder of a given chemical composition. The graphite powder nickel plating process was optimized, a regression equation was obtained, and the results of the dispersion analysis of regression coefficients were presented, indicating the adequacy and statistical significance of the obtained regression model. The thickness of nickel, copper and combined Cu-Ni coatings was determined by optical microscopy. It is shown that the electrolytic method of graphite powder metallization makes it possible to deposit continuous coatings with the formation of a shell (capsule) for each graphite particle. Presents the results of a study of the physicochemical properties of nickel-plated graphite powder (bulk density, fluidity, granulometric and chemical composition).

Dislocation and deformation analysis of Cu-Ni thin films during Nano-indentation using molecular dynamics simulation approach

Aim of this paper is to investigate the effect of varying the size of indenter, speed of indenter and thickness of nano-coating on hardness and dislocations. The dislocation mechanism, common neighbour analysis in Cu-Ni, is analysed by changing the distinctive parameters of indentation using molecular dynamics simulation approach. Overall indentation impact and mechanisms are studied with indentation velocity, indenter radius, and Nickel layer thickness. The embedded atom method based potential is used to describe the interaction between atoms. From the analysis it was seen that by applying varying thickness of nano-coating of nickel over a copper substrate, the hardness value increases corresponding with force as the thickness of nickel coating increases. Cu-50Ni is having more value of harness, which is 43% higher than pure Copper. The total length of dislocations for Cu-50Ni was 5% and 20% less than Copper and Cu-20Ni, respectively, determined by dislocation analysis at full load. From varying loading rate analysis, is was found that hardness value for Cu-Ni bilayer with loading rate of 1.5 Å/ps is maximum compared to other loading rates and is 7.40% and 36% more than Cu and Cu-Ni at a loading rate of 0.5 Å/ps, respectively. Then from by varying indenter radius, it was seen that the hardness value decreases with an increase in indenter radius. The hardness value of Cu-Ni with an indenter radius of 30 Å is 31% and 30% more than Cu and Cu-Ni with an indenter radius of 50 Å, respectively. The total length of dislocations for Cu-50Ni was 37% and 25% less than Cu and Cu-Ni with an indenter radius of 50 Å, which was determined by dislocation analysis at full load.

Nickel thin film preparation and its characterization as catalyst for HWC-in plasma-PECVD-growth graphene

Nickel thin film, aimed at catalyst layer for HWC-in plasma-PECVD-growth of graphene, has been deposited on SiO2 glass of microscope slide by thermal evaporation method. The thickness of the as-deposited Ni films was not uniform ranging from 200 nm to 700 nm as revealed from cross sectional SEM image. To reduce the film thickness and improve the crystal quality of the films, the samples were annealed in the furnace with three different temperatures, T = 400 °C, 500 °C, and 600 °C, for three hours. SEM images of the post-treatment indicated that the film thickness decreased to about 100–200 nm after annealed at 500 °C for 3 h. Increasing the annealing temperature to 600 °C leads the nickel atoms out of the substrate so that it leaves the substrate without nickel thin film anymore. The disappearing of the Nickel film after annealing at temperature 600 °C was confirmed by EDS spectrum examination which showed that there was no nickel element in the sample. Due to the loss of nickel thin film after annealing at 600 °C, we set the annealing temperature at 500 °C and optimized duration of annealing. It was found that after annealing for 4 h the obtained thickness of thin film was averagely 44 ± 6 nm with some spread piles on the film. Increasing annealing duration to 5 h lead to increasing the thickness of thin film nickel to be 66 ± 14 nm which seems contradict with our expectation. However, the tens order magnitude of thin film thickness obtained is the expected result for graphene growth.

Investigation of Strain‐Rate Effects in Ni/PU Hybrid Foams under Low‐Impact Velocities

Metal foams are often used as energy absorbers and lightweight materials. Inspired by a natural blueprint, open‐cell metal foams can significantly reduce the mass of a structure. The innovative manufacturing process of electrodeposition provides the possibility to customize the coating layer thickness of nickel (Ni) on a polyurethane (PU) precursor foam. Consequently, the mechanical properties can be adjusted according to the requirements of the expected application. Herein, quasistatic compression tests and low‐velocity impact tests are conducted on open‐cell Ni/PU hybrid foams to investigate the strain‐rate effects for strain rates in the range of 10−3 to 550 s−1. Furthermore, digital image correlation is performed with the intention of comparing the micromechanical deformation mechanisms under quasistatic loading with those under dynamic loading. For the first time, the heat evolution at different impact velocities of metal foams has been investigated with an infrared camera.

Investigation and characterization of coating and carburizing AISI 1011 steel

In this research work, the effect of coating layer thickness of nickel, which electrodeposited on low carbon steel AISI (1011), on mechanical properties has been studied. It also studied the mechanical properties of the carburized alloy at 950˚C at the time of carburizing five hours. It was found that fatigue strength for this alloy increased as thickness of the nickel-coated layer increased. Also, the carburized specimen has a fatigue strength higher than the untreated metal. The metal that was treated with the carburizing process and nickel plating for 15 minutes has the best fatigue strength. The fatigue strength improvement against non-plated specimens was between 3.93% and 16.87 % . Furthermore, hardness of metal increased for specimens treated with electrodeposition, and it became 219.7 Hv for metal coated with nickel at 15 minutes and had a coated layer of 20.42 µm. The hardness value became 431.65 Hv for carburized alloy treated with plating for 15 minutes. However, there was an improvement in the surface roughness due to electroplating.

Black silicon quality control by conditions of nickel-assisted etching of crystalline silicon surfaces in photovoltaic devices

Here we present a study of the nickel-assisted etching applied to form uniform black silicon layers on crystalline silicon substrates. We related the parameters used for technological process control (etchant, nickel thickness) to parameters of the obtained surface and explain the correlation using the etching model responsible for etching of the silicon covered by a thin nickel film. The increase in the thickness of the metal catalyst did not suppress the etching completely but allowed one to tune the roughness of the silicon surface. The rate of the electrochemical etching was additionally changed by adaptation of the proportion of components in the complex etchant. Depending on the intentionally selected conditions, the duration of the optimized process was from 3 to 10 min. The lowest optical reflection commonly accepted as the black silicon surface was obtained for the mixture with a low amount of the active etchant component. It was demonstrated that the method is acceptable to improve the characteristics of a photovoltaic cell.

On the fabrication of thin-film artificial metal grid resonator antenna arrays using deep x-ray Lithography

In this paper, a unique microfabrication approach for designing high permittivity, high gain and wideband thin-film artificial metal grid dielectric resonator antenna (GDRA) arrays for mm-wave applications is presented. Fabrication of the GDRAs with a strip template frame is based on deep-x-ray lithography (DXRL) using a 500 µm thick polymethylmethacrylate (PMMA) layer as the photoresist. The simple low-cost fabricated DXRL mask for exposure consisted of gold absorbers patterned by direct-write ultraviolet (UV) laser lithography on a carbon substrate. To avoid the trapping of gas bubbles in the dense, high aspect ratio (HAR) deep grid structures, a novel development approach was introduced utilizing in-vacuum, room temperature dip development to facilitate the collapse of forming gas bubbles. The developed voids were subsequently electroplated to a nickel thickness of 300 µm to obtain high permittivity artificial dielectrics. The paper describes the entire fabrication sequence. Also, the x-ray mask and DXRL structures are examined for dimensional accuracy and structural quality. This strip template frame approach has superior performance in terms of impedance bandwidth, gain and radiation efficiency as compared to the previously published solid template frame approach. For the purpose of the demonstration, a four-element GDRA array sample was fabricated and tested. A wide measured impedance bandwidth of 5 GHz from 58 GHz to 63 GHz and measured broadside radiation pattern with a peak gain of 10.9 dBi was achieved.

Modeling and Experimental Characterization of Nickel-Coated Copper Wires for the Design of Extremely High-Temperature Electrical Machines

The requirement for electrical machines operating at extremely high temperatures has prompted researchers to focus on new materials. The use of nickel-coated copper (Cu/Ni) wires can be a promising alternative to copper wires because of their resistance to oxidation at high temperatures. In this article, the characterization of Cu/Ni wires' electrical resistance in the frequency domain as well as the measurement of pure nickel's B(H) curve have been specified. The effect of nickel coated on a copper wire is remarkable in terms of electrical resistance at high frequencies because of the skin effect and eddy currents. An original model has been proposed for the prediction of the electrical resistance. The originality is to consider the bimetallic conductor as a transformer in order to generate its model. Since the analytical calculation is not possible because of the nonlinearity of the nickel's magnetic properties, a new numerical computational method for the determination of the impedances was proposed. The modeling results are correlated with the experimental tests made on 3 Cu/Ni wires: 0.3 mm diameter with 27% of nickel in volume and 0.5 mm diameter with 8 and 18 μm nickel thickness. This article, thus, provides essential information about the important parameters for the performance of electrical machines.

Optimal thickness of the catalytic nickel coating for the CVD synthesis of carbon nanomaterials

The effect of the thickness of a catalytic nickel coating deposited on a copper substrate by an electrochemical method on the intensity of formation of carbon nanomaterials in the CVD process was investigated. It was found that the dependence of the specific nanostructured carbon yield on the coating thickness is extremal, with a maximum near 1.5 μm. Qualitative interpretation of the obtained data is proposed on the basis of the carbon growth mechanisms on the catalytic coating.

Ni/4H-SiC interaction and silicide formation under excimer laser annealing for ohmic contact

Nickel silicidation reactions were activated on 4H-SiC using laser annealing at wavelength of 308 nm to study interaction and reaction of the involved atomic species. With this intent, the deposited nickel layer thickness was scaled from 100 nm to 10 nm and the laser fluence was spanned from 2.2 to 4.2 J/cm2. A combination of structural characterization by X-ray diffraction, Energy-Dispersive X-ray spectroscopy, Raman Spectroscopy, Transmission Electron Microscopy and morphological investigations through Scanning Electron Microscopy with theoretical predictions as a function of the applied laser fluence, have unveiled that the starting nickel thickness plays a main role, especially above the threshold for nickel melting (2.8 J/cm2). As a general paradigm, sufficient silicon release from the substrate occurs above this threshold that is available for silicidation, with amount increasing with the laser fluence. This addresses stoichiometry and morphology of the silicided contact that indeed depend on the available Nickel atoms (i.e., the Ni layer thickness) and on the thermal profile, as tested at a fixed fluence of 3.8 J/cm2. In addition, a layer-by-layer variable stoichiometry is established in each sample through the contact, with the deepest silicide being relatively more Si-rich. All those findings have impact on the electrical parameters of testing diodes. Based on data cross-linking, NiSi2 contacting layers and C-free interfaces provide a convenience in reducing resistance contributions.

Deformation behavior of core–shell nanowire structures with coherent and semi-coherent interfaces

Abstract

Electroless nickel–phosphorus plating on WC–Co powders using HVOF feedstock

ABSTRACTIn this study, electroless nickel–phosphorus plating was optimised for WC–Co powder using different bath loads and then subjected to a high-velocity oxygen fuel process. The produced Ni–P-coated WC–12Co powders were subsequently used as HVOF feedstock materials. Based on the SEM results, an increase in the bath load resulted in a decrease in the thickness of the Ni–P coating formed on the WC–12Co powders. Moreover, applying the HVOF process led to a lower porosity and roughness and a higher thickness of nickel coating, whereas applying a suitable thickness of this coating can prevent the destructive W2C phase. Finally, a bath load of 16 g L–1 was determined as the optimum value to achieve a proper thickness of the Ni–P, extremely low porosity (0.3%), good surface roughness (5 μm), and high microhardness (1112 Hv) in the produced coating.

Tailorable electromagnetic interference shielding using nickel coated glass fabric-epoxy composite with excellent mechanical property

Abstract Glass fibre fabric was coated with nickel using electroless plating technique. A suitable pre-treatment method was adopted to make the glass fabric surface catalytic. The glass fabric was coated to various thicknesses of nickel by varying the plating parameters. The effect of coating thickness on electromagnetic interference (EMI) shielding and absorption was studied in J (5.8–8.2 GHz), X (8.2–12.4 GHz) and Ku-(12.4–18 GHz) bands. The optimum coating thickness of 400 nm would be desirable to achieve shielding effectiveness of 30 dB in J, X and Ku-band (efficiency level of 99.9%). The absorption co-efficient was found to be dominant for coating thickness of ~ 32 nm. Further, a 3 mm thick epoxy-glass laminate was made by embedding a single layer of nickel coated glass fibre fabric with a coating thickness of ~ 6 µm. It was observed that in such a composite laminate with Ni coated fabric, EMI SE of ~ 50 dB could be achieved. It was also observed that the mechanical properties of the laminate bearing a Ni coated layer is better than the plain laminate as a result of improved interfacial characteristics in the presence of active Ni.

Solid-phase diffusion controlled growth of nickel silicide nanowires for supercapacitor electrode

This work reports on the influence of nickel (Ni) thickness on the growth of nickel silicide nanowires (NiSi NWs) using a solid-phase diffusion controlled growth treatment. The NiSi NWs were grown on two different substrates (i.e. crystal silicon (c-Si) and Ni foil) which were coated with Ni film with different thicknesses; 110 ± 5 and 220 ± 5 nm. FESEM images revealed that the shape, the size and the density of NiSi on both substrates were strongly dependent on the thickness of Ni film. These NWs exhibited morphology of straight NWs with diameter and length of between 16 to 23 nm and 2.9 to 3.9 µm, respectively. The NWs showed a single-crystalline Ni3Si2 phase with a preferred orientation in the (1 0 0) plane. XRD diffractogram proved that the formation of Ni-rich NiSi NWs is strongly dependent on the Ni film’s thickness rather than on the types of substrates. NiSi NF220 demonstrated the highest specific capacity with a maximum value of 313.3 C/g. This is attributed from the high density of NWs which endows more redox reaction and the high conductivity of Ni foil substrate that facilitated the high charge transfer kinetics. The fabricated NiSi NWs//activated carbon-based asymmetric supercapacitor exhibited the maximum energy density of 13.37 W h/kg at 200 W/kg and good cyclic stability with 79% capacity retention after 3000 cycles.

Direct electroplating of nickel on ABS plastic using polyaniline–silver surface composite synthesized using different acids

Nickel coating was directly electroplated on acrylonitrile butadiene styrene (ABS) plastic substrate using a new method. The substrate surface was first coated by thin polyaniline film, then silver particles were deposited on the surface in order to improve the electrical conductivity. Three different acids (perchloric, nitric, and sulfuric acid) were used to synthesize the primary polyaniline film. The method adopted in the present study was not based on incorporation of silver particles within the polyaniline matrix; rather, the silver was deposited on the substrate surface. The electrical conductivity of the samples was increased to a level high enough for direct electroplating of nickel. The sample synthesized using nitric acid showed the finest grain size (1.57 µm) and greatest thickness of the final nickel coating (57 µm). The sample synthesized using sulfuric acid exhibited the lowest electrical resistance (0.008 Ω). In addition, the nickel coating deposited on the surface of the sample synthesized using perchloric acid exhibited the strongest adhesion to the substrate (5B according to ASTM standard).