41,170 research outputs found

    Two electrodeposition strategies for the morphology-controlled synthesis of cobalt nanostructures

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    In this contribution, two different strategies are discussed to synthesize cobalt nanostructures: direct cobalt electrodeposition on a planar aluminum electrode and cobalt electrodeposition into nanoporous alumina templates generated by aluminum anodization (template electrodeposition). In the direct electrodeposition of cobalt on aluminum, cobalt nanoparticles are formed during the early stage of electrodeposition, which causes the depletion of cobalt ions near the electrode. Water reduction then takes place catalyzed by electrodeposited cobalt nanoparticles, which increases the pH near the electrode and can induce cobalt hydroxide precipitation. By varying the electrode potential and the cobalt ion concentration, the interplay between electrochemical growth of cobalt and water reduction could be controlled to induce transition from cobalt hexagonal nano-platelets to nanostructured films composed of cobalt nanoparticles and cobalt hydroxide nano-flakes. Cobalt nanowires can be synthesized by electrodeposition into nanoporous alumina templates generated by aluminum anodization. This approach typically involves the application of alumina templates produced by a two-step anodization procedure: the alumina nanoporous layer generated by a first anodization is dissolved in a chromic acid solution while a very ordered alumina nanoporous layer is produced by a second anodization stage. In accordance with previous studies, this procedure is fundamental to achieve uniform filling of the nanopores in the subsequent electrodeposition stage. In the present study, uniform filling of the nanoporous alumina generated by one-step anodization could be achieved by the electrodeposition of cobalt nanowires. This result was made possible by the application of a novel pulsed electrodeposition strategy

    Electrodeposition of Ni-Si Schottky barriers

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    Electrodeposition is being used to fabricate magnetic microstructures directly on patterned n-type Si wafers of various substrate resistivities. The Ni-Si Schottky barrier is characterized and found to be of high quality for relatively low Si resistivities (1-2 Omega(.)cm), with extremely low reverse leakage. It is shown that a direct correlation exists among the electrodeposition potential, the roughness, and the coercivity of the films. A conductive seed layer or a back contact is not compulsory for electrodeposition on Si with resistivities up to 15 Omega(.)cm. This shows that electrodeposition of magnetic materials on Si might be a viable fabrication technique for magnetoresistance and spintronics applications

    Direct electrodeposition of aluminium nano-rods

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    Electrodeposition of aluminium within an alumina nano-structured template, for use as high surface area current collectors in Li-ion microbatteries, was investigated. The aluminium electrodeposition was carried out in the ionic liquid 1-ethyl-3-methylimidazolium chloride:aluminium chloride (1:2 ratio). First the aluminium electrodeposition process was confirmed by combined cyclic voltammetry and electrochemical quartz crystal microbalance measurements. Then, aluminium was electrodeposited under pulsed-potential conditions within ordered alumina membranes. A careful removal of the alumina template unveiled free standing arrays of aluminium nano-rods. The nano-columns shape and dimensions are directly related to the template dimensions. To our knowledge, this is the first time that direct electrodeposition of aluminium nano-pillars onto an aluminium substrate is reported

    Electrodeposition from supercritical fluids

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    Recent studies have shown that it is possible to electrodeposit a range of materials, such as Cu, Ag and Ge, from various supercritical fluids, including hydrofluorocarbons and mixtures of CO2 with suitable co-solvents. In this perspective we discuss the relatively new field of electrodeposition from supercritical fluids. The perspective focuses on some of the underlying physical chemistry and covers both practical and scientific aspects of electrodeposition from supercritical fluids. We also discuss possible applications for supercritical fluid electrodeposition and suggest some key developments that are required to take the field to the next stage

    OPTIMIZATION OF SOLUTION POTENTIAL AND TEMPERATURE ON ION ELECTRODEPOSITION PROCESS OF COPPER (II) USING AN ADDITIVE OF FORMALDEHYDE

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    This research was conducted at the Chemical Research Laboratory of State University of Yogyakarta (UNY), Instruments Analysis Laboratory of Indonesian Islamic University (UII), and the Research Center for Physics of Indonesian Institute of Sciences (LIPI), Bandung. The purpose of this study was to determine the optimum solution potential and temperature on the electrodeposition process of Copper ion (II) using formaldehyde as an additive. The subject of this study was 400 ppm of copper solution. The object of this research was copper deposit on the cathode. Electrodeposition process used CuSO4 solution as a source of Cu ion (II), H2SO4 solution as supporting electrolyte, HNO3 solution as depolarizator, formaldehyde as an additive, and platinum plates as electrodes (cathode and anode). Electrodeposition process was done by potential variations of 2, 3, 4, 5 and 6 volts, the solution’s temperature variations of 27, 32, 37, 42 and 47°C and the deposition time of 25 minutes. Quantitative analysis was done by Atomic Absorption Spectrometry (AAS) to determine the concentration of Cu ion (II) after electrodeposition process. Qualitative analysis was by X-ray diffraction to determine crystal structures of Cu deposit of the electrodeposition on the optimum potential and temperature of the solution. The results showed that the optimum potential was 3 volts and the optimum temperature of the solution was 27°C. The concentration of Cu ion (II) of the electrodeposition on the solution’s optimum potential and temperature was 298.4750 ppm with the deposition efficiency of 25.38%. The crystal structure of Cu deposit of the electrodeposition on the solution’s optimum potential and temperature had a face-centered cubic system with a lattice parameter of 3.5877 A and the lattice planes of (111), (200), (220) and (311)

    Effect of Sugar Cane and Cassava Juices as Addition Agents in the Electrodeposition of Zinc from Acid Based Solution

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    An experimental investigation has been made into the effectiveness of some tropical agricultural resources, sugar cane and cassava juices, as addition agents in the electrodeposition of zinc from an acid chloride bath. The electrodeposition of zinc on steel was performed by the partial immersion of the steel specimen and the zinc electrodes in plating solution using a DC supplier. While a fairly good zinc electrodeposition on mild steel substrate could be obtained in the acid zinc chloride solution, using either cassava juice or sugar cane juice alone, the synergistic effect of the two juices combined gives a far better resul

    Crystal growing by electrodeposition from dense gaseous solutions

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    Single crystals and dendritic formations of silver are grown on platinum electrodes by electrodeposition from a dense gaseous solution of silver nitrate in ammonia. Process is modification of hydrothermal process, and also differs from standard electrodeposition by permitting single crystals to be grown from hydrogen-bonded solvents

    Alginate electrodeposition onto three-dimensional porous Co-Ni films as drug delivery platforms

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    Three-dimensional porous Co–Ni films/alginate hybrid materials have been successfully prepared by electrodeposition to be used as a steerable magnetic device for drug delivery. Firstly, 3D porous Co–Ni films were prepared as substrates for the subsequent electrodeposition of the alginate biopolymer. Cyclic voltammetry, galvanostatic and potentiostatic studies were performed to establish the best conditions to obtain porous Co–Ni films. The electrochemical experiments were carried out in an electrolyte containing the metal salts and ammonium chloride at low pHs. In a second stage, the electrochemical deposition of alginate as a biocompatible polymer drug delivery carrier was performed. The characteristics of the alginate matrix were investigated in terms of electrochemical properties, morphology and drug release. The hybrid material obtained showed soft-magnetic behavior and drug release indicating its suitability to be used as a steerable magnetic drug delivery device.Postprint (author's final draft
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