Nickel Silicon Research Articles

High strength C/Si‒Ni‒C composites fabricated by reaction melt infiltration with Si‒Ni alloy at lower temperature

AbstractSilicon‒nickel alloy (Si‒Ni) was first used for fabricating continuous carbon fiber reinforced ceramic matrix composites by reaction melt infiltration process. Based on Si‒Ni phase diagram, 66.7 at.% Si‒Ni was chosen, which has a lower liquidus temperature of 1115°C. The C/Si‒Ni‒C composites were infiltrated at temperature of 1270°C‒1390°C, and the prepared composite consists of C, SiC, NiSi, and NiSi2 phases. The density of the composite is higher than 2.29 g/cm3 and their open porosity is below 3%, indicating the composite was infiltrated completely by the Si‒Ni alloy. The C/Si‒Ni‒C composite exhibits significantly higher flexural strength and fracture toughness compared to the C/C‒SiC composite infiltrated with pure silicon at 1500°C. Specifically, the flexural strength and fracture toughness of the C/Si‒Ni‒C composite infiltrated at 1390°C increase by 140% and 300%, respectively. The improvement of mechanical properties contributed to the low reactivity between silicon‒nickel with carbon fibers, and the lower infiltration temperature, which can reduce degradation of carbon fiber as reinforcement. Moreover, the NiSi2 and NiSi alloy phases in the C/Si‒Ni‒C composite replace the brittle silicon phase in the C/C‒SiC composite, which can obviously enhance the fracture toughness.

Nickel–silicon interfacial adhesion strength measured by laser spallation

Thin films of amorphous silicon (a-Si) coated on metals such as nickel (Ni) are one of the most promising anode architectures for high-energy-density lithium-ion (Li-ion) batteries. The performance and longevity of batteries with this type of electrode depend on the integrity of the Ni/a–Si interface. The integrity of the a-Si /Ni bonded interface during cycling is critical, but the experimental characterization of interfacial failure of this material system is highly challenging and there is a sparsity of interface strength data in the literature. Here, we describe a laser spallation (LS) technique to characterize the interfacial adhesion strength of Ni/a–Si multilayer films created by chemical vapor deposition (CVD). The LS technique enables the non-contact measurement of the tensile interfacial strength with high precision when compared to conventional methods for characterizing adhesion. Interferometric measurement combined with finite element analysis shows that the Ni/a–Si interface, created via the CVD of a-Si on Ni surfaces can withstand ≈46–72 MPa in tension before failure initiation. To ensure successful and precise characterization of interfacial adhesion strength using LS, we further develop a design criterion for multi-layer samples by analyzing the thin-film mechanics. Our study provides insights into the strength of the Ni/a–Si interface that governs the performance and durability of high-energy-density anodes and offers design guidelines for improving thin-film electrode integrity.

On the Role of Friction Modifier Additives in the Oil Control Ring and Piston Liner Contact

Abstract In-cylinder internal combustion engine parasitic frictional losses continue to be an area of interest to improve efficiency and reduce emissions. This study investigates the frictional behavior at the oil control ring–cylinder liner conjunction of lubricants with anti-wear additives, varying dispersant concentration, and a range of friction modifiers. Experiments are conducted at a range of temperatures on a cylinder liner with a nickel silicon carbide coating. A novel motored reciprocating tribometer, with a complete three-piece oil control ring and cylinder liner, was used to isolate the friction at the segment–liner interfaces. Four lubricants were tested, three with the same 3% dispersant concentration and 1% zinc dialkyl dithiophosphate (ZDDP) anti-wear additive: the first with no friction modifier, the second with inorganic friction modifier (molybdenum dithiocarbamates), and the third with organic friction modifier (amide). A fourth lubricant with an organic friction modifier with a 9% dispersant concentration was tested to compare the effect of the level of dispersant with the friction modifier. Results indicate that the inorganic friction modifier reduces friction comparatively to the other lubricants, showing the importance of friction modifier selection with anti-wear additives.

Atomic Layer Deposition of LixCoyOz Cathodic Thin Films for Li-Ion Batteries

Atomic-Layer Deposition (ALD) is an appealing gas-phase technique for the deposition of thin solid cathodic films for 2D and especially 3D Li-ion microbatteries (Li-ion MBs). ALD relies on surface chemistry reactions and allows the fabrication of ultrathin pinhole free solid films with well controlled thickness, continuity and conformality. It has been shown to successfully cover 3D complex shapes for various applications including Li-ion MBs. Yet, a fairly low amount of work has been published on the realization by ALD of such cathodic active thin films. Typical cathodic materials are at least ternary compounds (including Lithium) which call for supercycles or multilayers approaches to synthesize them by ALD. As reminded for example by Maximov M. et al 1, the use of lithiated precursors complexifies the ALD fabrication due to, among others, Lithium high diffusivity and reactivity. In the case of LiCoO2 ALD synthesis for example, the only reported work to date is the one of Donders et al. 2 where the authors used CoCp2/LiOtBu as Cobalt/Lithium precursors respectively and O2 plasma as the oxidizing agent.The talk will describe the synthesis and characterizations of the LixCoyOzthin filmspreparedby a thermal ALD approach. It will detail the supercycle methods used as well as some of the investigations performed to explore the chemistry of the deposited films (Raman spectroscopy, X-Ray Photoelectron Spectroscopy, X-Ray Diffraction and Energy Dispersive X-Ray). The electrochemical performances of the films will also be shared and compared with the State of the art. 1 Maximov, M.; Nazarov, D.; Rumyantsev, A.; Koshtyal, Y.; Ezhov, I.; Mitrofanov, I.; Kim, A.; Medvedev, O.; Popovich, A. Atomic Layer Deposition of Lithium–Nickel–Silicon Oxide Cathode Material for Thin-Film Lithium-Ion Batteries. Energies 2020, 13, 2345. 2 Donders, M. E., ArnoldBik, W. M., Knoops, H. C. M., Kessels, W. M. M., & Notten, P. H. L. (2013). Atomic layer deposition of LiCoO2 thin film electrodes for all-solid-state Li-ion micro-batteries. Journal of the Electrochemical Society, 160(5), A3066-A3071.

Synergetic effect of porous silicon–Nickel composite on its solid-state hydrogen energy storage properties

Hydrogen is a clean and carbon-free energy reliable carrier to fulfill the energy supply requirement for an energy-sustainable society. Among different hydrogen energy storage techniques, solid-state hydrogen storage demonstrates elevated bulk density and gravimetric capacity and addresses safety concerns. The work studies the synergetic effect of porous Silicon (PS) as the host storage material and Ni as the catalyst in the composite form. The PS fabricated by electrochemical anodization is ball-milled with Ni powder to prepare the composite. The composite shows an improved hydrogen storage capacity of 1.64 wt% at 40 bar and 120 °C. The capacity increases to 2.69 wt% with the increase in pressure to 60 bar at 60 °C, indicating the large active surface. The physical and chemical changes to the composite are analyzed using SEM, XRD, and Raman spectroscopy. The differential scanning calorimetry shows the catalytic effect of Ni by reducing the decomposition temperature of individual PS. The synergetic effect of PS and Ni produces a synergetic effect that leads to the dissociation of molecules, improves hydrogen storage capacity, and reduces the temperature required for desorption.

A metamaterial absorber with a multi-layer metal–dielectric grating structure from visible to near-infrared

In this paper, we propose a multi-layer metal–dielectric grating consisting of multi-layer nickel–silicon nitride (Ni-SiNX) grating over a metallic Ni substrate as an ultra-broadband near-perfect absorber. The structure is not only simple in structure, but also superior in performance. Numerical analysis of the structure shows that it has an absorption rate of 99.24% in the wavelength range of 400–2000 nm. To achieve ultra-broadband and high absorption properties, the suggested absorber simultaneously creates excitation of propagating surface plasmon resonance (PSPR), local surface plasmon resonance (LSPR), and Fabry–Perot (FP) cavity. By analyzing the absorption performance of different incident angles and polarization waves, it is demonstrated that the broadband near-perfect absorption of the absorber exhibits insensitivity to the angle of the incident light. In addition, we discuss the effects of various metallic materials and parameters of geometric structures on the absorption characteristics in detail. Finally, we discussed the suggested scheme’s potential in terms of solar energy capture. Therefore, we anticipate that our proposed absorber can be applied in solar energy harvesting as well as broadband thermal emission.

Investigation of Microstructure and Wear Properties of Precipitates-Strengthened Cu-Ni-Si-Fe Alloy.

Based on multi-component alloys using precipitation hardening, a Cu-Ni-Si-Fe copper alloy was prepared and studied for hardness, electrical conductivity, and wear resistance. Copper Nickel Silicon (Cu-Ni-Si) intermetallic compounds were observed as precipitates, leading to an increase in mechanical and physical properties. Further, the addition of Fe was discussed in intermetallic compound formation. Moreover, microstructures, age hardening, and dry sliding wear resistances of the present alloy were analyzed and compared with C17200 beryllium copper. The results showed that the present alloy performed extraordinarily, with 314 HV in hardness and 22.2 %IACS in conductivity, which is almost similar to C17200 alloy. Furthermore, the dry sliding wear resistance of the present alloy was 2199.3 (m/MPa·mm3) at an ambient temperature, leading to an improvement of 208% compared with the C17200 alloy.

The impact of surfactants on the properties of electroless Ni–P–SiC coatings

The development and properties of electroless nickel silicon (Ni–P–SiC) coatings on steel substrates with different surfactants were investigated in this study. Different surfactant additives (anionic, cationic, and nonionic) were used to prevent the agglomeration of SiC nanoparticles in the coating bath. Their effect on the deposition rate, surface roughness, microhardness, and corrosion resistance of Ni–P–SiC coatings was investigated in this study. XRD, SEM, and EDS analysis was performed to observe the crystal structure, morphology, and chemical composition of the deposit. Potentiodynamic polarization tests, stylus surface measurement devices, and Vickers microhardness testers were used to explore the corrosion behavior, surface roughness, and microhardness of the coatings. The presence of the three surfactants at a 0.6 g/L concentration significantly influences the characteristics of the coatings. The maximum number of SiC nanoparticles was homogeneously distributed in the Ni alloy in the presence of a cationic surfactant. The coating developed from the cationic surfactant bath exhibited the highest microhardness, corrosion resistance, deposition rate, and smooth surface identified in the coating developed from the cationic surfactant bath.

Dry Sliding Tribological Behaviors of Electrodeposited Ni-GO/SiC Composite Coating on the 2218 Aluminum Alloy.

Electrodeposition has attracted tremendous interest in functional coatings due to its advantages of high efficiency, inexpensiveness and ease of implementation. In this work, nickel graphene oxide (Ni-GO), nickel silicon carbide (Ni-SiC) and nickel graphene oxide/silicon carbide (Ni-GO/SiC) composite coatings were electrodeposited on the 2218 aluminum alloy (2218AlA) substrate. The microstructure, microhardness, bonding strength and tribological behaviors of the composite coatings were carried out. According to the results obtained, the composite coatings were dense and compact, with no visible defects and microcracks, and well bonded to 2218AlA substrate. The microhardness of composite coatings was significantly increased compared to that of the 2218AlA substrate. The microhardness of Ni-SiC composite coating was the highest, reaching 3.14 times that of the 2218AlA substrate. The friction response time, friction coefficient and wear rate of the composite coatings were obviously lower. For the Ni-GO composite coating, the average friction coefficient is the smallest at 45.35% of the 2218AlA substrate, while the wear rate is the smallest at 46.97% of the 2218AlA substrate. However, the comprehensive tribological performances of the Ni-GO/SiC composite coating were superior. The abrasive and adhesive wear were the main wear mechanisms of composite coatings, but the degree of damage was different.

Исследования комплексного дефектообразования в кремнии, легированном никелем

The behavior of nickel and hydrogen impurities in silicon has been studied by deep-level transient spectroscopy (DLTS) and Raman spectroscopy. It is shown that the vibrations of Ni and H atoms in Si are in the range of 925-985 cm-1. The DLTS spectra in n - and p -type silicon doped with Ni atoms exhibit two deep levels with energies Ev +0.17 eV and Ec -0.42 eV. It was found that during chemical etching in Si doped with Ni, various hydrogen-bonded defect complexes are formed, the energies of which are Ec -0.18 eV, Ec -0.54 eV, Ev +0.26 eV, and Ev +0.55 eV.

Direct Observation of Induced Graphene and SiC Strengthening in Al–Ni Alloy via the Hot Pressing Technique

In this study, Al/5 Ni/0.2 GNPs/x SiC (x = 5, 10, 15, and 20 wt%) nanocomposites were constituted using the powder metallurgy–hot pressing technique. The SiC particles and GNPs were coated with 3 wt% Ag using the electroless deposition technique then mixed with an Al matrix and 5% Ni using ball milling. The investigated powders were hot-pressed at 550 °C and 600 °C and 800 Mpa. The produced samples were evaluated by studying their densification, microstructure, phase, chemical composition, hardness, compressive strength, wear resistance, and thermal expansion. A new intermetallic compound formed between Al and Ni, which is aluminum nickel (Al3Ni). Graphene reacted with the Ni and formed the nickel carbide Ni3C. Additionally, it reacted with the SiC and formed the nickel–silicon composite Ni31Si12 at different percentages. A proper distribution for Ni, GNs, and SiC particles and excellent adhesion were observed. No grain boundaries between the Al matrix particles were discovered. Slight increases in the density values and quite high convergence were revealed. The addition of 0.2 wt% GNs to Al-5Ni increased the hardness value by 47.38% and, by adding SiC-Ag to the Al-5Ni-0.2GNs, the hardness increased gradually. The 20 wt% sample recorded 121.6 HV with a 56.29% increment. The 15 wt% SiC sample recorded the highest compressive strength, and the 20 wt% SiC sample recorded the lowest thermal expansion at the different temperatures. The five Al-Ni-Gr-SiC samples were tested as an electrode for electro-analysis processes. A zinc oxide thin film was successfully prepared by electrodeposition onto samples using a zinc nitrate aqueous solution at 25 °C. The electrodeposition was performed using the linear sweep voltammetric and potentiostatic technique. The effect of the substrate type on the deposition current was fully studied. Additionally, the ohmic resistance polarization values were recorded for the tested samples in a zinc nitrate medium. The results show that the sample containing the Al-5 Ni-0.2 GNs-10% SiC composite is the most acceptable sample for these purposes.

Clustering of Si–Ni in cementite in 18MND5 steel weldment

ABSTRACT In this work, a new phenomenon—clustering of Si–Ni in cementite was observed in a thermal aged 18MND5 weldment and the formation mechanism was briefly discussed. 18MND5 weldment mock-up was thermally aged at 400°C for 3000 h and its microstructure and composition were investigated by SEM, TEM and 3DAP. Silicon–nickel clusters in cementite were observed in the heat-affected zone of 18MND5 base metal by atom probe tomography. The formation of Si–Ni cluster in cementite is closely linked to the welding, tempering and thermal aging processes. This clustering phenomenon might be explained by that in the process of cementite formation, an alloying element ‘spike’ generated ahead of the interface of cementite and α-Fe matrix based on the partition local equilibrium model and silicon atoms were trapped for Mn, Cr and Mo ‘spikes’ act as a barrier to Si diffusion. As a result of thermal aging, those trapped Si atoms were compelled to generate metastable clusters in cementite for lowering the free energy.

СТРУКТУРООБРАЗОВАНИЕ ПРИМЕСНЫХ ПРЕЦИПИТАТОВ НИКЕЛЯ В КРЕМНИИ

In this study, using the method of electron probe analysis, the sequence of formation of various impurity precipitates of nickel in silicon in the process of diffusion doping at a temperature of T = 1573 K was investigated. The influence of the value of the cooling rate of the samples after diffusion annealing on the formation of impurity precipitates was considered. The morphological parameters of impurity precipitates of nickel in silicon have been revealed, and their chemical compositions have been determined. It was found that, depending on the size and shape, the nickel precipitates can have a single or multilayer structure

Nickel and gold identification in p-type silicon through TDLS: a modeling study

In Silicon, impurities introduce recombination centers and degrade the minority carrier lifetime. It is therefore important to identify the nature of these impurities through their characteristics: the capture cross sectionσand the defect levelEt. For this purpose, a study of the bulk lifetime of minority carriers can be carried out. The temperature dependence of the lifetime based on the Shockley-Read-Hall (SRH) statistic and related to recombination through defects is studied. Nickel and gold in p-type Si have been selected for the SRH lifetime modeling. The objective of the analysis is to carry out a study to evaluate gold and nickel identification prior to temperature-dependent lifetime measurements using the microwave phase-shift (μW-PS) technique. The μW-PS is derived from the PCD technique and is sensitive to lower impurity concentrations. It has been shown that both gold and nickel can be unambiguously identified from the calculated TDLS curves.

High‐Pressure Deformation of Iron–Nickel–Silicon Alloys and Implications for Earth’s Inner Core

AbstractEarth’s inner core exhibits strong seismic anisotropy, often attributed to the alignment of hexagonal close‐packed iron (hcp‐Fe) alloy crystallites with the Earth’s poles. How this alignment developed depends on material properties of the alloy and is important to our understanding of the core’s crystallization history and active geodynamical forcing. Previous studies suggested that hcp‐Fe is weak under deep Earth conditions but did not investigate the effects of the lighter elements known to be part of the inner core alloy. Here, we present results from radial X‐ray diffraction experiments in a diamond anvil cell that constrain the strength and deformation properties of iron‐nickel‐silicon (Fe–Ni–Si) alloys up to 60 GPa. We also show the results of laser heating to 1650 K to evaluate the effect of temperature. Observed alloy textures suggest different relative activities of the various hcp deformation mechanisms compared to pure Fe, but these textures could still account for the theorized polar alignment. Fe–Ni–Si alloys are mechanically stronger than Fe and Fe–Ni; extrapolated to inner core conditions, Si‐bearing alloys may be more than an order of magnitude stronger. This enhanced strength proportionally reduces the effectivity of dislocation creep as a deformation mechanism, which may suggest that texture developed during crystallization rather than as the result of postsolidification plastic flow.

Decay of Impurity Clusters of Nickel and Cobalt Atoms in Silicon under the Influence of Pressure

Decay of Impurity Clusters of Nickel and Cobalt Atoms in Silicon under the Influence of Pressure

Hot compression behaviour and microstructural evolution in aluminium based composites: an assessment of the role of reinforcements and deformation parameters

The response of two different types of aluminium matrix composites (AMCs) reinforced with silicon carbide ceramic particulates or nickel metallic particulates to hot compression testing parameters was evaluated. The composites were produced via two-step stir-casting technique. Axisymmetric compression testing was performed on the samples at different deformation temperatures of 220 and 370 °Ϲ, 0.5 and 5 s−1 strain rates and total strains of 0.6 and 1.2. The initial and post-deformed microstructures were studied using optical and scanning electron microscopy. The results show that flow stress was significantly influenced by imposed deformation parameters and the type of reinforcements used in the AMCs. Nickel particulate reinforced aluminium matrix composite (AMC) showed superior resistance to deformation in comparison with silicon carbide reinforced AMC under the different testing conditions. In both AMCs, work hardening, dynamic recovery and dynamic recrystallisation influenced their response to imposed parameters. The signature of dynamic recrystallisation was very apparent in aluminium matrix composite reinforced with nickel particulates.

Improving the quality of bars from special alloy of the copper—nickel—silicon system

Possibilities of improving the quality of a special wear-resistant and heat-resistant alloy Cu—Ni—Si of the copper — nickel — silicon system used in the production of special-purpose electro-vacuum devices are analyzed.

Synthesis and electrochemical performance of silicon-nanowire alloy anodes.

High-capacity materials are required in order to address the environmental concerns of our modern society, ultimately leading to safe and eco-friendly high-energy batteries. Silicon-nanowire anodes (SiNWs) have the potential to significantly increase the energy density of lithium-ion batteries (LIBs). In order to improve the mechanical durability and the electrochemical performance of SiNW-anodes, we fabricated a silicon–nickel (SiNi) composite anode by electroless deposition of nickel, followed by annealing at high temperature to obtain nickel silicides of different content and composition. The morphology of SiNi-alloy anodes was examined by SEM, in situ TEM and EDS methods in order to understand how different deposition protocols affect the coating of the silicon nanowires. The formation of Ni-silicides was found to occur during thermal treatment at 900 °C. Despite the incomplete shell coverage of SiNWs composed of multiple phases and grains, the electrochemical performance of binder-free and conducting-additive-free SiNi-alloy anodes showed stable electrochemical behavior and higher capacity retention compared to the pristine SiNW anode. Li/SiNW–SiNix cells ran at C/2 rate for 200 reversible cycles, exhibiting 0.1%/cycle capacity loss after completion of the SEI formation.

Atomic Layer Deposition of Lithium–Nickel–Silicon Oxide Cathode Material for Thin-Film Lithium-Ion Batteries

Lithium nickelate (LiNiO2) and materials based on it are attractive positive electrode materials for lithium-ion batteries, owing to their large capacity. In this paper, the results of atomic layer deposition (ALD) of lithium–nickel–silicon oxide thin films using lithium hexamethyldisilazide (LiHMDS) and bis(cyclopentadienyl) nickel (II) (NiCp2) as precursors and remote oxygen plasma as a counter-reagent are reported. Two approaches were studied: ALD using supercycles and ALD of the multilayered structure of lithium oxide, lithium nickel oxide, and nickel oxides followed by annealing. The prepared films were studied by scanning electron microscopy, spectral ellipsometry, X-ray diffraction, X-ray reflectivity, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and selected-area electron diffraction. The pulse ratio of LiHMDS/Ni(Cp)2 precursors in one supercycle ranged from 1/1 to 1/10. Silicon was observed in the deposited films, and after annealing, crystalline Li2SiO3 and Li2Si2O5 were formed at 800 °C. Annealing of the multilayered sample caused the partial formation of LiNiO2. The obtained cathode materials possessed electrochemical activity comparable with the results for other thin-film cathodes.