A direct electrochemical route from oxide precursors to the terbium–nickel intermetallic compound TbNi5

Qiu, Guohong; Wang, Dihua; Jin, Xianbo; Chen, George

doi:10.1016/j.electacta.2006.03.019

Cited by 61 publications

(45 citation statements)

References 20 publications

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“…2 TbNi alloys can be applied for ferromagnetisms and hydrogen storage. 3 Metallic Ni is conventionally prepared by direct electrolysis in sulfate solutions. However, it is still a desire to develop new methods for getting nickel from different resources.…”

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confidence: 99%

Metallic Nickel Preparation by Electro-Deoxidation in Molten Sodium Hydroxide

Zhang

Jiao

et al. 2015

J. Electrochem. Soc.

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The preparation of nickel powders by electro-deoxidation of nickel oxide in molten sodium hydroxide at 550 • C has been investigated. Cyclic voltammetry on different electrodes was applied to study the electrochemical reaction mechanism of the reduction of NiO in the melt. In addition, NiO pellets were reduced by constant voltage electrolysis for different times. The results disclose that the reduction of nickel oxide is a one-step reaction and the side reaction, hydrogen evolution, may lower the current efficiency during the constant voltage electrolysis. The current efficiency increases from 25.9% to 87.2% with the addition of sodium oxide which leads to a higher cathodic potential for the hydrogen evolution reaction and, therefore, prevents it occurring. With using an inert nickel anode, oxygen gas emits during the electrolysis. Nickel, as a key raw material, has been widely applied as structural and magnetic materials due to its excellent physical and chemical properties. Nickel is always added to steels to enhance the corrosion resistance. Nickel hydroxide electrodes are used widely in the Ni-Cd, Ni-Zn and Ni-MH storage batteries.1 Ni-Ti shape memory alloys have attracted much interest for their use as functional materials in many engineering applications (such as adaptive and smart structures).2 TbNi alloys can be applied for ferromagnetisms and hydrogen storage. Metallic Ni is conventionally prepared by direct electrolysis in sulfate solutions. However, it is still a desire to develop new methods for getting nickel from different resources. [4][5][6] Electro-deoxidation of solid oxides, which were used as cathode in molten salts, provided an approach to prepare nickel from nickel oxide. Qiu et al. reported the reduction mechanism of NiO in molten CaCl 2 using a cavity electrode for the electrochemical investigation. 8 It was also reported that nickel alloys could be obtained when NiO mixed with other oxides such as MgO, TiO 2 were served as cathodes in molten CaCl 2 .2,9 However, due to the high corrosive property and high melting point of calcium chloride, it is not easy to find a cheap inert anode to replace carbon anode which generates carbon dioxide. Cox et al. investigated the reduction process of Fe 2 O 3 in molten sodium hydroxide at 530• C and proved that nickel rod could be used as an inert anode during the electrolysis in the melt. The purpose of this work is to investigate the mechanism of electrodeoxidation of NiO to Ni in the sodium hydroxide melt at 550• C. In a change from normal procedure, cyclic voltammetry has been carried out on different electrodes to gain an insight into the mechanism. Constant voltage electrolysis has been conducted to prepare nickel. Besides, a high-resolution mass spectrometry was connected to the system to analyze the outlet gas to further investigate the reactions in progress. ExperimentalA nickel crucible packed with 180 g anhydrous NaOH was placed in a sealed vertical tubular reactor, and heated to 300• C for at least 12 h under a vacuum condition to decompose...

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confidence: 99%

Metallic Nickel Preparation by Electro-Deoxidation in Molten Sodium Hydroxide

Zhang

Jiao

et al. 2015

J. Electrochem. Soc.

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“…In addition, the morphology of the cell around three TNZT materials prepared by different preparation conditions were similar to Specimen M. However, the cells surrounding the titanium metal were scattered obviously. More seriously, the cell clusters around the vanadium titanium alloy had nearly died due to dissolution of toxic vanadium ions from vanadium titanium alloy, causing physical harm for the cell [13]. Therefore, we can get the following conclusions for the cytotoxicity of materials:…”

Section: Morphology Of the Cells Around Metallic Materialsmentioning

confidence: 87%

Preparation of Titanium Alloys through Molten Salt Electrolysis of Solid Oxides for Medical Implants

Li¹,

Wu²,

Shi³

et al. 2017

Proceedings of the 3rd Workshop on Advanced Research and Technology in Industry (WARTIA 2017)

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Abstract:A simple, cost-efficient, energy-saving, electrochemical process is developed to synthesize the biomedical Ti-based metal-containing Group VB (V, Nb, Ta) implant materials in the small size at 900 ºC. The anhydrous CaCl 2 and solid oxides were used as the salt melt medium and raw reactants, respectively. The mechanism of the reduction process was discussed by constant cell voltage electrolysis of different time periods. The as-prepared samples, such as Ti-12.5Zr-2.5Nb-2.5Ta, were characterized by SEM, EDX, elemental and biological analysis (including cell compatibility test, etc.). Because of the green synthesis, non-toxicity, and good biocompatibility, Ti-12.5Zr-2.5Nb-2.5Ta exhibited promise for medical implant materials.

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“…5 shows the CVs of the Mo-SiO 2 electrode with consecutive potential cycle scans at a scan rate of 20 mV/s. On the CV of the bare Mo electrode, calcium deposition was clearly seen by the large reduction currents near the negative end of the potential window [18]. The potential at which the current began to be larger from the background was chosen as the internal ref.…”

Section: Voltammetric Features Of the Mo-sio 2 Electrodementioning

confidence: 99%

“…In electro-deoxidation process, in order to avoid CaCl 2 decomposition and achieve relatively high electro-deoxidation rate, the electrolysis voltages should be selected carefully [18]. According to thermodynamic data, the decomposition voltage of CaCl 2 and SiO 2 at 900 1C was calculated as follows:…”

Section: Influence Of Cell Voltagementioning

confidence: 99%

“…So far, most of the published works using the electrodeoxidation method have been focused on the fabrication of numerous metals and alloys powders, such as Ti [12], Cr [13], Ta [14], Si [15], Ti x Si y intermetallic compounds [16], TbFe 2 [17], AB 5 -type [18][19][20] and AB 2 -type [21] Hydrogen storage alloys, directly from their metal oxides. Meanwhile, functional coatings prepared by the electro-deoxidation method have also been demonstrated [22].…”

Section: Introductionmentioning

confidence: 99%

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