Nickel Boride Research Articles

Synthesis of nickel boride by thermal explosion in ball-milled powder mixtures

In this work, a synthesis route of Ni3B, an attractive material for making heating elements and a promising component for catalysts, was developed using high-energy ball milling of nickel and boron powder mixtures. The milling duration was varied from 1 to 15 min. Ball milling led to partial dissolution of boron in the crystalline lattice of nickel and crystallite size refinement of nickel. Heating of the ball-milled mixtures at a constant rate led to thermal explosion, the indications of which were a rapid temperature rise and the formation of boride phases. The duration of ball milling was shown to influence the phase composition of the products of thermal explosion. The time of milling ensuring the formation of single-phase Ni3B was determined to be 7 min. The ignition temperature of thermal explosion decreased with the milling time: a decrease by more than 300 °C was observed for the mixture milled for 15 min relative to the non-milled mixture. The maximum temperature developed during thermal explosion increased in the mixture milled for 1 min relative to the non-milled mixture and then decreased with the milling time reaching the level of the non-milled mixture after 15 min of milling. The observed dependence of the maximum temperature on the milling time is related to the net effect of mixing uniformity improvement between the reactants and a partial transformation of the reaction mixtures into Ni(B) solid solutions and Ni3B during milling. The proposed synthesis route of a single-phase Ni3B powder has advantages of short processing time and low-energy consumption.

Characterization of microstructure and properties of electroless duplex Ni-W-P/Ni-P nano-ZrO2 composite coating

In this study, we prepared the Ni-W-P/Ni-P nano-ZrO2 nanocomposite coating by electroless chemical deposition methods. The structures, morphologies, and corrosion behavior of the nanoparticle enhanced duplex coating were evaluated by X-ray diffraction, atomic force microscopy, scanning electron microscopy as well as the electrochemical methods, such as the potentiodynamic polarization curve and electrochemical impedance spectroscopy. The Ni-W-P/Ni-P nano-ZrO2 duplex coatings were amorphous under the as-plated condition and crystallized and produced nickel borides upon heat-treatment. The duplex coatings exhibit the higher microhardness after different heat treatments and also depict the better corrosion resistance than conventional Ni-P coating in the H2S/CO2-containing environment. This novel type of Ni-P coating possesses both excellent mechanical properties and good corrosion resistance, and it would expand their scope of applications in H2S/CO2-containing environment.

Synthesis of amorphous boride nanosheets by the chemical reduction of Prussian blue analogs for efficient water electrolysis

Amorphous cobalt–nickel boride nanosheets are synthesised by the chemical reduction of Prussian blue analogs, and demonstrate comparable and bifunctional electrocatalytic activity for cost-efficient overall water splitting.

Nickel boride mediated chemoselective deprotection of 1,1-diacetates to aldehydes and deprotection with concomitant reduction to alcohols at ambient temperature

ABSTRACTA variety of 1,1-diacetates have been chemoselectively and efficiently deprotected to the corresponding aldehydes as well as deprotected and concomitantly reduced to the corresponding alcohols in high yields at ambient temperature with nickel boride generated in situ using different molar ratios of sodium borohydride and nickel (II) chloride in methanol at room temperature. Deprotection and reduction of a variety of aromatic, aliphatic and heterocyclic acylals have been achieved efficiently. Mild reaction conditions, easy work-up, high yields and chemoselectivity demonstrate the efficiency of this new method.

Facile synthesis of Ni3B/rGO nanocomposite as an efficient electrocatalyst for the oxygen evolution reaction in alkaline media

Alkaline water electrolysis yielding H2 and O2 is a very promising fuel cell technology for sustainable energy generation. Emphasis has been placed on the development of efficient electrocatalysts based on earth-abundant elements for the kinetically deterred oxygen evolution reaction (OER). Nickel boride nanostructures exhibit enhanced OER catalytic activity, achieving 10mAcm−2 at an overpotential of 320mV. The activity can be greatly improved by incorporating Ni3B in an electrically conducting reduced graphene oxide matrix, which reduces the overpotential further to 290mV at 10mAcm−2, and has a small Tafel slope. The catalytic activity of the Ni3B–rGO nanocomposite shows considerable stability under long-term operating conditions.

Fine Structure Study of the Plasma Coatings B4C-Ni-P

The article considers structure of coatings formed of the B4C-Ni-P powder. The coatings were deposited using air-plasma spraying with the unit for annular injection of powder. The pipes from steel 20 (0.2 % C) were used as a substrate. The structure and phase composition of the coatings were studied by optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. It is shown that high-density composite coatings consisting of boron carbide particles distributed in the nickel boride metal matrix are formed using air-plasma spraying. The areas with round inclusions characterized by the increased amount of nickel, phosphorus and boron are located around the boron carbide particles. Boron oxides and nickel oxides are also present in the coatings. Thin interlayers with amorphous-crystalline structure are formed around the boron carbide particles. The thickness of these interlayers does not exceed 1 μm. The metal matrix material represents areas with nanocrystalline structure and columnar crystals.

Boron and Boron‐Containing Catalysts for the Oxidative Dehydrogenation of Propane

AbstractBoron nitride was recently identified as a highly selective catalyst for the oxidative dehydrogenation of propane. In this communication, we report that other boron‐containing materials such as boron carbide, titanium boride, nickel boride, cobalt boride, hafnium boride, and tungsten boride, as well as elemental boron itself, show the same exceptional behavior as boron nitride. X‐ray photoelectron and infrared spectroscopy suggest oxyfunctionalization of the surface. This observation disproves previous mechanistic hypotheses that edge sites on the boron nitride would be the active sites and rather suggests the formation of an analogous surface‐stabilized BOx active site for all tested boride catalysts.

Catalytic Reductions and Tandem Reactions of Nitro Compounds Using in Situ Prepared Nickel Boride Catalyst in Nanocellulose Solution.

A mild and efficient method for the in situ reduction of a wide range of nitroarenes and aliphatic nitrocompounds to amines in excellent yields using nickel chloride/sodium borohydride in a solution of TEMPO-oxidized nanocellulose in water (0.01 wt %) is described. The nanocellulose has a stabilizing effect on the catalyst, which increases the turnover number and enables low loading of nickel catalyst (0.1-0.25 mol % NiCl2). In addition, two tandem protocols were developed in which the in situ formed amines were either Boc-protected to carbamates or further reacted with an epoxide to yield β-amino alcohols in excellent yields.

In Situ Solid-Gas Reactivity of Nanoscaled Metal Borides from Molten Salt Synthesis.

Metal borides have mostly been studied as bulk materials. The nanoscale provides new opportunities to investigate the properties of these materials, e.g., nanoscale hardening and surface reactivity. Metal borides are often considered stable solids because of their covalent character, but little is known on their behavior under a reactive atmosphere, especially reductive gases. We use molten salt synthesis at 750 °C to provide cobalt monoboride (CoB) nanocrystals embedded in an amorphous layer of cobalt(II) and partially oxidized boron as a model platform to study morphological, chemical, and structural evolutions of the boride and the superficial layer exposed to argon, dihydrogen (H2), and a mixture of H2 and carbon dioxide (CO2) through a multiscale in situ approach: environmental transmission electron microscopy, synchrotron-based near-ambient-pressure X-ray photoelectron spectroscopy, and near-edge X-ray absorption spectroscopy. Although the material is stable under argon, H2 triggers at 400 °C decomposition of CoB, leading to cobalt(0) nanoparticles. We then show that H2 activates CoB for the catalysis of CO2 methanation. A similar decomposition process is also observed on NiB nanocrystals under oxidizing conditions at 300 °C. Our work highlights the instability under reactive atmospheres of nanocrystalline cobalt and nickel borides obtained from molten salt synthesis. Therefore, we question the general stability of metal borides with distinct compositions under such conditions. These results shed light on the actual species in metal boride catalysis and provide the framework for future applications of metal borides in their stability domains.

DC Electric Arc Furnace Application for Production of Nickel-Boron Master Alloys

In this study, nickel-boron (Ni-B) alloys were produced via a carbothermic reduction starting from boric acid (H3BO3) with high-purity nickel oxide (NiO), charcoal, and wood chips in a direct current arc furnace. In electric arc furnace experiments, different starting mixtures were used, and their effects on the chemical compositions of the final Ni-B alloys were investigated. After the reduction and melting stages, Ni-B alloys were obtained by tapping from the bottom of the furnace. The samples from the designated areas were also taken and analyzed. The chemical composition of the final alloys and selected samples were measured with wet chemical analysis. The Ni-B alloys had a composition of up to 14.82 mass% B. The phase contents of the final alloys and selected samples were measured using x-ray diffraction (XRD). The XRD data helped predict possible reactions and reaction mechanisms. The material and energy balance calculations were made via the XRD Rietveld and chemical compositions. Nickel boride phases started to form 600 mm below the surface. The targeted NiB phase was detected at the tapping zone of the crucible (850–900 mm depth). The energy consumption was 1.84–4.29 kWh/kg, and the electrode consumption was 10–12 g/kg of raw material charged.

Catalytic activity of nanoscale borides: Co2B and Ni7B3 in the liquid-phase hydrogenation of citral

Metal borides are unconventional heterogeneous catalysts. Now, two compounds – the new phase Ni7B3 and well-known Co2B – were synthesized as well-defined, nanoscale material. After characterization (X-ray diffraction, scanning electron microscopy, nitrogen physisorption) they were tested for the liquid phase hydrogenation of citral (3,7-dimethyl-2,6-octadienal) in n-hexane at different temperatures. Hydrogenation products such as geraniol, nerol, citronellal and citronellol were analyzed. The Ni-free catalyst Co2B results in the formation of nerol and geraniol or citronellol selectively, depending on the reaction time. The new compound Ni7B3 yields citronellal or citronellol, depending on the temperature. Thus, the hydrogenation potential of borides – obtained as well-characterized, unsupported heterogeneous catalysts by a one-pot synthesis procedure and post-synthetic annealing – is demonstrated. The cobalt boride preferentially hydrogenates CO bonds, while the nickel boride is selective for CC double bonds.

Co3O4 nanoneedle@electroactive nickel boride membrane core/shell arrays: A novel hybrid for enhanced capacity

Exploring novel hybrid materials with efficient microstructure using facile approaches is highly urgent in designing supercapacitor electrodes. Here, the Ni-B membrane was used for coating the porous Co3O4 nanoneedle arrays which supported on the nickel foam (NF) frameworks through a rapid chemical reduction process (denoted as NF/Co3O4@NiB). The Ni-B membrane both provided sufficient active sites for redox reactions and inhibited the aggregation of formed hybrid architectures. Benefiting from the unique structural design and strongly coupled effects between porous Co3O4 arrays and Ni-B membrane, the resulted NF/Co3O4@NiB electrode exhibited high areal capacitance of 3.47Fcm−2 (0.48mAhcm−2) at a current density of 2.5mAcm−2, an excellent rate capability while maintaining 95.5% capacity retention after 2000 cycles. The asymmetric supercapacitor constructed with the NF/Co3O4@NiB as positive electrode and hierarchical porous carbon (HPC) as negative electrode also showed ideal capacitive behavior, and simultaneously delivered high energy and power densities. The easily decoration of Ni-B membrane on various active nanoarrays may arouse more novel design about hybrid architectures for large-scale applications.

Highly active and durable electrocatalytic water oxidation by a NiB0.45/NiOx core-shell heterostructured nanoparticulate film

On the way to energy-efficient and cost-effective hydrogen production by electrochemical or photoelectrochemical water splitting, it is of primary importance to develop highly active and durable water oxidation electrocatalysts based on earth-abundant elements. Here we report a highly active, robust, cheap, and facilely fabricated O2-evolving catalyst on a Cu foil, NiB0.45-250/Cu, which forms a NiB0.45/NiOx core-shell heterostructured nanoparticulate film during anodic electrolysis. The performance of NiB0.45-250/Cu, to produce 10mAcm−2 at 296mV overpotential in 1M KOH over 60h, is at par with the best efficiency of earth-abundant electrocatalysts reported to date and surpasses that of IrO2-loaded copper electrode under identical conditions. Experimental evidence and theoretical calculations reveal the correlations of B/Ni atomic ratio and annealing temperature with the morphology, surface microtexture, electrochemical active surface area, and electrical conductivity of NiBx films. Optimal combination of these factors can evidently enhance the catalytic activity of nickel boride electrocatalysts.

Ultrathin High Surface Area Nickel Boride (NixB) Nanosheets as Highly Efficient Electrocatalyst for Oxygen Evolution

The overriding obstacle to mass production of hydrogen from water as the premium fuel for powering our planet is the frustratingly slow kinetics of the oxygen evolution reaction (OER). Additionally, inadequate understanding of the key barriers of the OER is a hindrance to insightful design of advanced OER catalysts. This study presents ultrathin amorphous high‐surface area nickel boride (NixB) nanosheets as a low‐cost, very efficient and stable catalyst for the OER for electrochemical water splitting. The catalyst affords 10 mA cm−2 at 0.38 V overpotential during OER in 1.0 m KOH, reducing to only 0.28 V at 20 mA cm−2 when supported on nickel foam, which ranks it among the best reported nonprecious catalysts for oxygen evolution. Operando X‐ray absorption fine‐structure spectroscopy measurements reveal prevalence of NiOOH, as well as Ni‐B under OER conditions, owing to a Ni‐B core@nickel oxyhydroxide shell (Ni‐B@NiOxH) structure, and increase in disorder of the NiOxH layer, thus revealing important insight into the transient states of the catalyst during oxygen evolution.

Crystallinity‐Modulated Electrocatalytic Activity of a Nickel(II) Borate Thin Layer on Ni3B for Efficient Water Oxidation

AbstractThe exploration of new efficient OER electrocatalysts based on nonprecious metals and the understanding of the relationship between activity and structure of electrocatalysts are important to advance electrochemical water oxidation. Herein, we developed an efficient OER electrocatalyst with nickel boride (Ni3B) nanoparticles as cores and nickel(II) borate (Ni‐Bi) as shells (Ni‐Bi@NB) via a very simple and facile aqueous reaction. This electrocatalyst exhibited a small overpotential of 302 mV at 10 mA cm−2 and Tafel slope of 52 mV dec−1. More interestingly, it was found that the OER activity of Ni‐Bi@NB was closely dependent on the crystallinity of the Ni‐Bi shells. The partially crystalline Ni‐Bi catalyst exhibited much higher activity than the amorphous or crystalline analogues; this higher activity originated from the enhanced intrinsic activity of the catalytic sites. These findings open up opportunities to explore nickel(II) borates as a new class of efficient nonprecious metal OER electrocatalysts, and to improve the electrocatalyst performance by modulating their crystallinity.

Crystallinity-Modulated Electrocatalytic Activity of a Nickel(II) Borate Thin Layer on Ni3 B for Efficient Water Oxidation.

The exploration of new efficient OER electrocatalysts based on nonprecious metals and the understanding of the relationship between activity and structure of electrocatalysts are important to advance electrochemical water oxidation. Herein, we developed an efficient OER electrocatalyst with nickel boride (Ni3 B) nanoparticles as cores and nickel(II) borate (Ni-Bi ) as shells (Ni-Bi @NB) via a very simple and facile aqueous reaction. This electrocatalyst exhibited a small overpotential of 302 mV at 10 mA cm-2 and Tafel slope of 52 mV dec-1 . More interestingly, it was found that the OER activity of Ni-Bi @NB was closely dependent on the crystallinity of the Ni-Bi shells. The partially crystalline Ni-Bi catalyst exhibited much higher activity than the amorphous or crystalline analogues; this higher activity originated from the enhanced intrinsic activity of the catalytic sites. These findings open up opportunities to explore nickel(II) borates as a new class of efficient nonprecious metal OER electrocatalysts, and to improve the electrocatalyst performance by modulating their crystallinity.

Corrosion Behavior of Hard Boride Layer Produced on Nimonic 80A-Alloy by Gas Boriding

The gas boriding in N2–H2–BCl3 atmosphere was applied in order to produce a wear resistant surface layer on Nimonic 80A-alloy samples. The microstructure, microhardness and corrosion resistance of the boride layer were investigated. The produced layer consisted mainly of the compact boride zone (with average thickness 71 μm), including the mixture of nickel and chromium borides of high hardness (up to 1861 HV). In order to evaluate the corrosion behavior, the two methods of corrosion tests were used: potentiodynamic corrosion test in 5% NaCl solution and immersion corrosion test in a boiling solution of H2O, H2SO4 and Fe2(SO4)3. The results showed that gas boriding could provide the excellent corrosion resistance if the whole surface of a Nimonic 80A-alloy sample was covered by the continuous boride layer. Otherwise, as a consequence of selective boriding, the significant difference in electrochemical potentials caused an accelerated uniform corrosion of the base material.

Nanomechanical properties of gas-borided layer produced on Nimonic 80A-alloy

Abstract Diffusion borided layers, fabricated on Ni-based alloys, were characterized by improved hardness and wear resistance. In this paper, gas boronizing in N 2 –H 2 –BCl 3 atmosphere was proposed to produce the ceramic phases (borides) on Nimonic 80A-alloy. This process was carried out at 920 °C (1193 K) for 2 h. The microstructure was studied in detail using scanning electron microscope and energy-dispersive X-ray microanalysis. The boride layer consisted of a mixture of nickel borides (Ni 3 B, Ni 2 B, Ni 4 B 3 , NiB) and chromium borides (CrB, Cr 2 B). The nanomechanical properties (Young's modulus and hardness) were examined using the nanoindenter with a Berkovich diamond tip. The load-displacement curves and the indentation images were shown for the selected measurements. The identified phases in microstructure were very fine, therefore it was impossible to measure the hardness and Young's modulus of a defined phase. However, the percentage of chromium and nickel borides’ mixtures was calculated based on the measurements of indentation hardness ( H IT ) compared to the previous work. It enabled to calculate Poisson's ratio for a specified indentation. As a consequence, the indentation moduli E IT were determined. The higher values of H IT and E IT were obtained in case of indents, performed in the areas of higher percentage of chromium borides.

Influence of gas boriding on corrosion resistance of Inconel 600-alloy

Purpose: The aim of this study was to analyse the corrosion behaviour of gas-borided layers produced on Inconel 600-alloy. Two types of the borided layers were produced: fully borided and partially borided layer. The results obtained for gas-borided specimens were compared to untreated Inconel 600-alloy. Design/methodology/approach: In this paper, gas boriding in N2-H2-BCl3 atmosphere was applied to produce the boride layers on Inconel 600-alloy. This process was carried out at 910°C (1193 K) for 2 h. Microstructure observations were carried out using a light microscope. The hardness measurements were performed using a Vickers method under a load of 0.981 N. In order to evaluate the corrosion resistance, the immersion corrosion test in a boiling solution of H2O, H2SO4 and Fe2(SO4)3 was used. Findings: The gas-borided layers consisted of a mixture of nickel borides (Ni3B, Ni2B, Ni4B3, NiB) and chromium borides (CrB, Cr2B). The high thickness of compact boride layer (76-79 μm) as well as high hardness (up to 2061 HV) were obtained. Based on corrosion resistance tests it was found that in case of untreated sample the strong intergrannular attack was observed. Whereas the corrosion behavior ofgas-borided Inconel 600-alloy was more complicated and resulted from the surface condition. Research limitations/implications: The obtained results indicated that gas-boriding in N2-H2-BCl3 atmosphere could be a suitable corrosion protection if the whole surface would be covered with boride layer. Practical implications: The parameters of gas boriding in N2-H2-BCl3 atmosphere used in this study (temperature of 910°C for 2 h) allowed to produced layers of a higher thickness in comparison with other acceptable method of boriding e.g. powder-pack boriding. Originality/value: Based on the results it was found that gas-boriding in N2-H2-BCl3 atmosphere is a suitable method to protect Inconel 600-alloy from corrosion.

Microstructure and Mechanical Properties of Borided Inconel 625 Superalloy

The Ni- based superalloy Inconel 625 is extensively used owing to its high strength, excellent fabricability, good weldability and outstanding resistance to high temperature corrosion against aggressive environments. However, despite its unique properties and extensive use, its wear resistance is in some cases unsatisfactory. In this study, Inconel 625 was subjected to boriding treatments at different temperature and different durations. Microstructural characterization was made by conventional methods (scanning electron microscopy, optic microscopy, X-ray diffraction analysis) and mechanical characterization was made by microhardness and micro-abrasion wear test. Micro-abrasion wear tests were conducted against a AISI 52100 steel under 5, 7.5 and 10 N load in a 25 wt.% SiC slurry at room temperature. Microstructural results revealed that multi-phase boride layer (nickel boride, chrome boride and iron boride) and silicide layer were formed. The hardness and thickness of the boride layers were found to be 1175--2432 HV0.1 and, 6.61 -- 92.03 I¼m, respectively. Depending on the boriding temperature and time. In spite of silicide layer formation the wear resistance of borided Inconel 625 alloy increased up to 8 times thanks to the increase in the surface hardness which was caused by boriding process. The boriding treatment caused a transition in the wear mechanism. While grooving was observed in the untreated Inconel 625 samples, mixed (grooving and rolling) and rolling type wear was predominant in the borided samples.