Nickel Boride Research Articles

Ni-B 분말의 기계적 합금화 과정에서 밀링시간에 따른 미세조직과 상변화 거동

In this study, the effect of milling time on the microstructure and phase transformation behaviors of Ni-12 wt.%B powders was investigated using vibratory ball milling process. X-ray diffraction patterns showed that the phase transformation of mixed Ni-B elemental powder occurred after 50 hours of milling, with a formation of nickel boride phases. Through the study of microstructures in mechanical alloying process, it was considered that ball milling strongly accelerates solid-state diffusions of the Ni and B atoms during mechanical alloying process. The results of X-ray photoelectron spectroscopy showed that most of B atoms in the powder were linked to Ni with a formation of nickel boride phases after 200 hours of milling. It was finally concluded that mechanical alloying using ball milling process is feasible to synthesize fine and uniform nickel boride powders.

Sodium Borohydride‐Nickel Chloride‐Methanol Catalytic System for Regioselective Reduction of Electron‐Rich Conjugated Dienes and Reductive Cleavage of Allyl Esters Involving π‐Allylnickel Intermediates

AbstractThe regioslective reduction of electron‐rich dienes to monoolefins and the reductive cleavage of allyl esters were fulfilled by employing a sodium borohydride‐nickel chloride‐methanol catalytic system with exceedingly simple manipulations and high functional group tolerability. Both of the reductive reactions may involve π‐allylnickel intermediates generated from fresh nickel boride.

ChemInform Abstract: Total Synthesis of Rutaecarpine and Analogues by Tandem Azido Reductive Cyclization Assisted by Microwave Irradiation.

AbstractA convenient three‐step synthesis is presented for rutaecarpine (Va) and analogues such as euxylophoricine A (Vb) and C (Vc) involving a microwave‐assisted nickel boride reduction in the final cyclization step.

Reductive Studies on 3-Oxidopyrylium-alkene [5 + 2] Cycloadducts: Access to Some Hydroxy Cycloheptenoids

The scope of nickel boride as a versatile reducing reagent is extended to the 3-oxidopyrylium-alkene [5 + 2] cycloadducts. In this report, we demonstrate that nickel boride is capable of one-pot 1,2- and 1,4-reduction of enones present in the cycloadducts in good yields. Subsequent elaboration of the cycloadducts towards synthesis of functionalized cycloheptenoid derivatives devoid of the oxa-bridge is also explored.

Performance and Property of Ni Base Coatings by Using Plasma Arc Technology for 18Cr2Ni4WA Steel Repairing

To understand the structure and performance of Ni base coatings on 18Cr2Ni4WA steel, the key techniques of plasma arc cladding method are introduced. Microstructure and microhardness of the coating clad were analyzed by using Vickers hardness tester,scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).Results show that the phase of the coating is composed of γ-Ni solid solution， nickel boride Ni3B，carbide Cr27C6 and Cr2B3 type chromium boride. The coating has no cracks and does not exhibit porosity, the bonding between layers is compact and the boundaries are not observed. The coating is featured by a homogenized microstructure; small grain and no evident heat-affected zone.

Facile Synthesis of Pure Boron Nanotubes and Nanofibers

ABSTRACTA facile and scalable chemical vapor deposition (CVD) process in flowing argon using a solid instead of a reactive gaseous boron precursor has been carried out to synthesize crystalline boron nanostructures comprising of relatively straight boron nanotubes (BNTs) and nanofibers (BNFs). The synthesis involves the use of solid magnesium boride as the boron and magnesium catalyst precursor, nickel boride as co-catalyst, and MCM-41 zeolite as the growth template. The BNTs and BNFs produced have a narrow distribution of diameters between about 10 nm to 20 nm and lengths from about 500 nm to above 1 μm. Scanning and transmission electron microscope (SEM and TEM) imaging together with electron energy loss spectroscopy (EELS) and energy dispersive spectroscopy (EDS) have been conducted to characterize the structure, morphology and growth mechanism of these novel nanostructures. High resolution TEM imaging has been used to identify BNTs and BNFs in the nanostructures synthesized.

Highly Size-Controlled, Low-Size-Dispersity Nickel Nanoparticles from Poly(propylene imine) Dendrimer−Ni(II) Complexes

Reported here is the highly controlled synthesis and subsequent characterization of low-size-dispersity (±8−21%) crystalline Ni(0) nanoparticles derived from a dendrimer-ligand-based method employing amine-terminated poly(propylene imine) dendrimers, DAB-Amn. Crystalline Ni(0) nanoparticles devoid of any nickel boride are obtained by anaerobic borohydride reduction in methanol of DAB-Amn−Ni(II)x, as determined by high-resolution X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), and selected-area electron diffraction (SAED) measurements. Nickel nanoparticles with highly tunable diameters ranging from l.9 to 2.7 nm are readily obtained by methanolic borohydride reduction of Ni(II) coordinated to the primary amines of five different generations of DAB-Amn (n = 4, 8, 16, 32, 64). Control over the diameter of the Ni nanoparticles is readily achievable and inversely related to dendrimer generation and the NH2:Ni(II) ratio, n/x. These outcomes bode well for future...

ChemInform Abstract: Room Temperature Synthesis of Nickel Borides via Decomposition of NaBH4 Promoted by Nickel Bromide.

AbstractThe reaction of anhydrous THF and pentane dispersions of NaBH4 and NiBr2 of different concentrations (2.52, 5.46, 7.37, and 10.18 mol%) at room temperature and pressure yield amorphous black solid powders of nickel borides.

Microstructure and Properties of Ni-Base Coatings Obtained by Micro-Plasma Arc Cladding Processes

Microstructure and properties of Ni-base coatings obtained by micro-plasma arc cladding was investigated. A uniform clad coating was obtained after optimizing the cladding parameters by using NiCrBSi powder. Microstructure of the coatings observed by optical and scanning electron microscopy (SEM) indicated a homogenized microstructure. It has no evident heat-affected zone and no porosity. The phase of the coating was formed by γ-N solid solution, nickel boride Ni3B, carbide Cr21.34Fe1.66C6 and Cr2B3 type chromium boride. Although it likes the laser cladding coatings, micro-plasma coatings has its own characteristic. In addition, the average microhardness and nanohardness of coatings which were much higher than the substrate were observed, and the distribution of the microhardness was drawn.

Influence of deposition temperature and heat treatment on the performance of electroless Ni–B films

Electroless nickel–boron (Ni–B) was synthesized on mild steel or copper surface. The deposition of thin electroless Ni–B films using an acidic bath having nickel chloride as a source of nickel and dimethylamine borane (DMAB) as a reducing agent and operated at low temperature has been investigated in this paper. The effect of the plating time and temperature on the quality of Ni–B coatings was estimated. The results revealed that the plating rate decreases with increasing plating time and increases with increasing plating temperatures. The boron (B) content of the electroless Ni–B layer increased with increasing temperature. The resulting surfaces were examined and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). XRD analysis was performed to investigate structural modifications. Microhardness, corrosion and oxidation resistance of electroless as-plated and heat-treated Ni–B coatings, were evaluated. The effect of heat treatment temperature on the phase structure and microhardness of Ni–B coated at different temperatures was discussed. XRD patterns reveal that electroless Ni–B coatings deposited at 60 and 80°C are amorphous in as-plated condition and undergo phase transformation to crystalline nickel and nickel borides upon heat-treatment. Heat treatment achieved significant improvement in the microhardness and corrosion resistance due to the formation of the Ni–B compound phases (Ni3B).

Room-Temperature Synthesis of Nickel Borides via Decomposition of NaBH4 Promoted by Nickel Bromide

We report the formation of nickel borides, at room temperature and pressure, from the decomposition of NaBH(4) promoted by the addition of nickel bromide at different concentrations in a dispersing organic medium, tetrahydrofuran and pentane. The nickel borides, formed as amorphous powders, were analyzed, and the structure information served as input for modeling a periodic lattice structure with the same composition. Experimentally, the nickel boride phases were predominantly composed of a boron-rich phase with composition NiB(3). Combining FT-IR, X-ray diffraction analyses, and theoretical structure determination, we suggest for it a monoclinic structure, with symmetry group P2(1)/c, lattice parameters a =3.038 Å, b = 8.220 Å, c = 5.212 Å, α = β = 90.00° and γ = 87.57°. The enthalpies of formation of the nickel boride phases, as well as the lattice stability, were calculated using density functional theory and density functional perturbation theory methods.

Nickel Boride

Nickel boride (Ni2B), first reported in the pioneering work of Schlezinger and Brown [¹] and traditionally used as a catalyst for hydrogenation, [²] has more recently found a niche as a reducing agent in its own right. [³] Its ease of preparation, handling, and versatility as a reducing agent promise nickel boride its deserved attention from academic and industrial sectors. Nickel boride has been employed for a wide range of transformations including reductive dehalogenation of organic halides [4] , reductive amination of carbonyl compounds, [5] desulfurization of a variety of thioxo compounds, [6] deoxygenation of sulfoxides and selenoxides, [7] and reducing of nitrogen functionalities. [8] Of late, the reagent is being explored in the form of a nickel boride silica nanocomposite catalyst for hydrogen production from NaBH4 hydrolysis. [9]

Nickel Boride–Mediated Cleavage of 1,3-Dithiolanes: A Convenient Approach to Reductive Desulfurization

1,3-Dithiolanes are rapidly cleaved by nickel boride, generating corresponding hydrocarbons in excellent yields. The hydrogenolysis is rapid at room temperature and does not require protection from the atmosphere. Mild reaction conditions, simple workup, and good yields of pure products are some of the major advantages of the procedure.

ChemInform Abstract: Desulfurization of Benzo- and Dibenzothiophenes with Nickel Boride.

ChemInform Abstract: Desulfurization of Benzo- and Dibenzothiophenes with Nickel Boride.

Microstructure and interfacial reactions between B6O and (Ni, Co) couples

The search for suitable additives for boron suboxide (B6O) materials which could improve densification, reduce sintering temperature and tailor the microstructure has been of great importance. In an earlier study it was shown that transition metal borides qualify as sintering aids for B6O, but partial segregations of the boride secondary phases were found. In this work, efforts have been made to understand the chemical interaction between the B6O and boride phase. A reaction couple of sintered B6O, nickel and green compact B6O were assembled and heat-treated at 1850 8C for 20 min. XRD and SEM examinations of the reaction zone show the formation of nickel boride, diffusing into the B6O matrix and a substantial grain growth of B6O at the interface. # 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Protecting-Group-Free and Catalysis-Based Total Synthesis of the Ecklonialactones

A concise and protecting-group-free total synthesis of optically pure ecklonialactones A (1) and B (2) is described. The successful route to these oxylipins isolated from various brown algae involves five transition-metal-catalyzed transformations in the longest linear sequence of 13 steps. The first chiral center was set by a rhodium-catalyzed 1,4-addition of an alkenyl boronate to the commercial butenolide 11, which was controlled by Carreira's carvone-derived diene ligand 21. Other key steps involve a ring-closing olefin metathesis effected by the ruthenium indenylidene complex 22 for the formation of the five-membered carbocycle, a vanadium-catalyzed, hydroxy-directed epoxidation, and a ring-closing alkyne metathesis (RCAM) to forge the macrocyclic ring. Because of the unusually high propensity of the oxirane of the ecklonialactones for ring-opening, this transformation was best achieved with [(Ph(3)SiO)(3)Mo[triple bond]CPh].OEt(2) (34) as the catalyst, which is a representative of a new generation of highly tolerant yet remarkably efficient molybdenum alkylidyne complexes. The ancillary triphenylsilanolate ligands in 34 temper the Lewis acidity of the molybdenum center and are not able to nucleophilically open the fragile epoxide ring. The final reduction of the cycloalkyne formed in the RCAM step to the required (Z)-alkene was accomplished either by Lindlar reduction or with the aid of nickel boride.

Fabrication of nickel boride-coated carbon nanotube films by electrophoresis and electroless deposition for electrochemical hydrogen storage

Network-like carbon nanotube (CNT) films free of polymer binder were deposited directly onto a stainless steel substrate by electrophoresis. Results of experiments indicated that a CNT film with duplex surface treatment (nitric acid etching and nickel boride coating) provides satisfactory electrochemical hydrogen storage. Nitric acid treatment increased the hydrogen storage capacity of the CNT film due to the opening of CNTs, the formation of micropores in the CNT surface, and the improvement of surface wettability. Coating the CNT film with nickel boride (Ni 2B) greatly improved the electrochemical activity of the film and consequently increased the hydrogen storage capacity. The optimal amount of nickel boride coating on the CNT film was found to be about 45 wt%. Smaller amounts of nickel boride cannot provide enough electrochemical activity. Excessive nickel boride, on the other hand, leads to a decrease in the number of active sites on CNTs that are available for hydrogen storage.

ChemInform Abstract: Synthesis of Aspidospermidine Alkaloids from 1,2,3,4-Tetrahydrocarbazole: Total Stereoselective Synthesis of (.+-.)-18-Noraspidospermidine.

Abstract The reactivity of the 1,2,3,4-tetrahydrocarbazol-4-one derivatives has been analysed and applied to the synthesis of (±)-18-noraspidospermidine (1b). This was synthesised, starting from 4-(1′,3′-dioxolan-2′-yl)cyclohexanone which was successively transformed to 3-methyl-3-(3′-nitropropyl)-1,2,3,4-tetrahydrocarbazol-4-one and to the imine tetracycle 13 by means of nickel boride catalyst. The reduction of 13 to the natural cis D ring junction was carried out with the LiAlH 4 AlCl 3 system. The construction of the E-ring was carried out by a Pummerer type reaction from thecis-7-tosyl-1-phenylthioacetamide derivative 17 by oxidation followed by intramolecular cyclisation, desulfurization and reduction to 1b.

ChemInform Abstract: Enantioselective Borane Reduction of Ketones with Oxazaborolidines Boron-Bound to Nickel Boride Nanoparticles.

Abstract A variety of substituted acetophenones can be reduced with high enantioselectivity by using borane and the heterogeneous catalyst derived from the reaction of (1 S ,2 R )-(+)-2-amino-1,2-diphenylethanol with nickel-boride nanoparticles.

ChemInform Abstract: Reductive Amination of Aromatic Aldehydes and Ketones with Nickel Boride.

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