Electrodeposition

Distribution by Scientific Domains

Terms modified by Electrodeposition

  • electrodeposition method
  • electrodeposition process

  • Selected Abstracts


    Quasi-two-dimensional electrodeposition growth of Pb0.5Sn0.5 alloy

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2006
    Bin Sun
    Abstract Electrodeposition of Pb0.5Sn0.5 alloy is carried out in a quasi-2D electrochemical cell. As the growth proceeds the morphologies of the deposits transit from cake-like to branched and finally to the compact morphology. We show that these morphological transitions arise from the changes in the transport mechanisms of the ions in the electrolyte cell. In addition, it is found that the current density on the growth interface can vary spontaneously due to the irregular shape of the deposit and the generation of hydrogen gas. It causes the formation of the complex microstructure with non-uniform composition. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    Catalytic Effect on Silver Electrodeposition of Gold Deposited on Carbon Electrodes

    ELECTROANALYSIS, Issue 19 2004
    Alfredo de, Escosura-Muñiz
    Abstract A new methodology, based on silver electrocatalytic deposition and designed to quantify gold deposited onto carbon paste electrode (CPE) and glassy carbon electrode (GCE), has been developed in this work. Silver (prepared in 1.0,M NH3) electrodeposition at ,0.13,V occurs only when gold is previously deposited at an adequate potential on the electrode surface for a fixed period of time. When a CPE is used as working electrode, an adequate oxidation of gold is necessary. This oxidation is carried out in both 0.1,M NaOH and 0.1,M H2SO4 at oxidation potentials. When a GCE is used as working electrode, the oxidation steps are not necessary. Moreover, a cleaning step in KCN, which removes gold from electrode surface, is included. To obtain reproducibility in the analytical signal, the surface of the electrodes must be suitably pretreated; this electrodic pretreatment depends on the kind of electrode used as working electrode. Low detection limits (5.0×10,10,M) for short gold deposition times (10,min for CPE and 5,min for GCE) were achieved with this novel methodology. Finally, sodium aurothiomalate can be quantified using silver electrocatalytic deposition and GCE as working electrode. Good linear relationship between silver anodic stripping peak and aurothiomalate concentration was found from 5.0×10,10,M to 1.0×10,8,M. [source]


    Electrodeposition of Lead at Boron-Doped Diamond Film Electrodes: Effect of Temperature

    ELECTROANALYSIS, Issue 12 2003
    César Prado
    Abstract The electrodeposition of lead on boron-doped diamond has been studied with a view to identifying the fundamental parameters controlling the sensitivity and lower detection limit in anodic stripping voltammetry. Chronoamperometric transients are used to explore the deposition, indicating a progressive growth mechanism confirmed by ex situ AFM images. Linear sweep ASV experiments show a threshold concentration of ca 10,6,M below which no lead is detected; this is attributed to the need for nucleation of the solid phase on the electrode. Experiments with variable temperature show that this threshold can be usefully lowered at elevated temperatures. [source]


    Biomorphic Silicon Carbide Coated with an Electrodeposition of Nanostructured Hydroxyapatite/Collagen as Biomimetic Bone Filler and Scaffold,

    ADVANCED ENGINEERING MATERIALS, Issue 8 2010
    M. Lelli
    Abstract The paper describes the method of preparation and chemical/physical characterization of a new biomaterial to be used as a bone substitute and bone-tissue engineering scaffold, which synergistically joins a porous bio-inspired morphology and the mechanical properties of biomorphic silicon carbide (BioSiC) with the surface bioactivity of a nanostructured hydroxyapatite/collagen biomimetic coating. FT-IR spectroscopy and XRD techniques are utilized to determine the chemical coating's composition. The morphology and size of the inorganic and protein components are investigated by TEM. The characteristic morphology of BioSiC channels and pores, which differ as a function of the transversal or longitudinal cross-section and with etching time, are investigated by SEM. Natural wood transformed into BioSiC acts as a cathode in an electrochemically assisted process that produces on its surface a biomimetic coating of hydroxyapatite nanocrystals and reconstituted type I collagen fibrils, producing an innovative apatite/collagen biomimetic porous bone filler and scaffold for tissue engineering. [source]


    Perfectly Ordered, Free-Standing Nanowire Arrays With Controllable Geometry,

    ADVANCED ENGINEERING MATERIALS, Issue 11 2009
    Adam Philip Robinson
    We demonstrate a novel focused ion beam (FIB) based technique for the production of substrate-supported, free-standing, perfectly ordered nanowire arrays with control over the pore geometry, pitch, diameter, and length. A FIB may be used to influence the site of pore formation in ultra-thin (<1 µm) oxide nanoporous templates adhered to substrates. Electrodeposition through the template results in the production of nanowire arrays with controlled, perfect ordering. [source]


    The Optimal Grain Sized Nanocrystalline Ni with High Strength and Good Ductility Fabricated by a Direct Current Electrodeposition,

    ADVANCED ENGINEERING MATERIALS, Issue 6 2008
    X. Shen
    In this work, six pure Ni specimen which mean grain sizes spans a broad range from ultra-fine to nanometer were fabricated by direct current electrodeposition and a coarse grain Ni was obtained by annealing. A gradual transition of the crystallographic preferred orientation of the deposited Ni from (200) texture to isotropic or random orientation with decreasing the mean grain size was revealed by XRD. [source]


    In-Film Bioprocessing and Immunoanalysis with Electroaddressable Stimuli-Responsive Polysaccharides

    ADVANCED FUNCTIONAL MATERIALS, Issue 10 2010
    Xiaohua Yang
    Abstract Advances in thin-film fabrication are integral to enhancing the power of microelectronics while fabrication methods that allow the integration of biological molecules are enabling advances in bioelectronics. A thin-film-fabrication method that further extends the integration of biology with microelectronics by allowing living biological systems to be assembled, cultured, and analyzed on-chip with the aid of localized electrical signals is described. Specifically, the blending of two stimuli-responsive film-forming polysaccharides for electroaddressing is reported. The first, alginate, can electrodeposit by undergoing a localized sol,gel transition in response to electrode-imposed anodic signals. The second, agarose, can be co-deposited with alginate and forms a gel upon a temperature reduction. Electrodeposition of this dual polysaccharide network is observed to be a simple, rapid, and spatially selective means for assembly. The bioprocessing capabilities are examined by co-depositing a yeast clone engineered to display a variable lymphocyte receptor protein on the cell surface. Results demonstrate the in-film expansion and induction of this cell population. Analysis of the cells' surface proteins is achieved by the electrophoretic delivery of immunoreagents into the film. These results demonstrate a simple and benign means to electroaddress hydrogel films for in-film bioprocessing and immunoanalysis. [source]


    Electrodeposition of Inorganic/Organic Hybrid Thin Films

    ADVANCED FUNCTIONAL MATERIALS, Issue 1 2009
    Tsukasa Yoshida
    Abstract Electrodeposition of inorganic compound thin films in the presence of certain organic molecules results in self-assembly of various hybrid thin films with new properties. Examples of new discoveries by the authors are reviewed, taking cathodic formation of a ZnO/dye hybrid as the leading example. Hybridization of eosinY leads to the formation of highly oriented porous crystalline ZnO as the consequence of dye loading. The hybrid formation is a highly complicated process involving complex chemistry of many molecular and ionic constituents. However, electrochemical analyses of the relevant phenomena indicate the possibility of reaching a comprehensive understanding of the mechanism, giving us the chance to further develop them into industrial technologies. The porous crystals are ideal for photoelectrodes in dye-sensitized solar cells. As the process also permits the use of non-heat-resistant substrates, the technology can be applied for the development of colorful and light-weight plastic solar cells. [source]


    Formation of Highly Crystallized ,-PbO Thin Films by Cathodic Electrodeposition of Pb and Its Rapid Oxidation in Air,

    ADVANCED FUNCTIONAL MATERIALS, Issue 2 2005
    S. Sawatani
    Abstract The process of electrodeposition of ,-PbO thin films from aqueous solutions of PbII salts has been studied in detail. Contrary to the mechanism assumed in previous studies, thin films of crystalline ,-PbO are obtained after cathodic electrolysis in aqueous solutions of various soluble salts of PbII (Pb(NO3)2, Pb(ClO4)2, and Pb(CH3COO)2), and in both the presence and the absence of O2, thus indicating no contribution of OH, generation by electroreduction of NO3, and/or O2 to the formation of ,-PbO. A gradual color change is noted: a freshly electrodeposited gray film turns yellow as it dries in air. Drying of the films under controlled atmosphere (Ar or O2), combined with scanning electron microscopy (SEM) observation and X-ray diffraction (XRD) measurement, has revealed that freshly deposited films are of metallic Pb, which are oxidized and converted into ,-PbO. Such a reaction is operative only when a freshly electrodeposited activated wet Pb film is in contact with gaseous O2. Despite the rapid conversion of a solid material, the resultant ,-PbO thin films are highly crystallized and possess highly ordered internal nanostructure. Elongated nanoparticles (30,nm,×,100,nm) are assembled in a regular alignment to compose a large platelet (greater than 10,,m in size) with single-crystalline character, as revealed by transmission electron microscopy (TEM) observation and selected-area electron diffraction (SAED) measurement. [source]


    Creating In-Plane Metallic-Nanowire Arrays by Corner-Mediated Electrodeposition

    ADVANCED MATERIALS, Issue 35 2009
    Bo Zhang
    A novel template-assisted electrochemical approach to fabricate in-plane arrays of copper nanowires with tunable width varying from 25,nm to more than 200,nm, which is realized by successive nucleation of copper at the concave corner of the polymer template and the substrate, is reported. We demonstrate that this method can be applied for fabricating complicated structures. [source]


    Fabrication of Three-Dimensional Photonic Crystals Using Multibeam Interference Lithography and Electrodeposition

    ADVANCED MATERIALS, Issue 29 2009
    Masao Miyake
    High-quality 3D photonic crystals are fabricated through electrodeposition into a polymer template created by multibeam interference lithography. Complete infilling of the template is achieved through electrodeposition of Cu2O, and subsequent etching of the template results in a Cu2O/air photonic crystal with the exact inverse structure of the template (see figure). The resultant photonic crystal shows a high peak reflectance at theoretically predicted wavelength. [source]


    Numerical algorithms for modelling electrodeposition: Tracking the deposition front under forced convection from megasonic agitation

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 3 2010
    Michael Hughes
    Abstract Electrodeposition is a widely used technique for the fabrication of high aspect ratio microstructures. In recent years, much research has been focused within this area aiming to understand the physics behind the filling of high aspect ratio vias and trenches on substrates and in particular how they can be made without the formation of voids in the deposited material. This paper reports on the fundamental work towards the advancement of numerical algorithms that can predict the electrodeposition process in micron scaled features. Two different numerical approaches have been developed, which capture the motion of the deposition interface and 2-D simulations are presented for both methods under two deposition regimes: those where surface kinetics is governed by Ohm's law and the Butler,Volmer equation, respectively. In the last part of this paper the modelling of acoustic forces and their subsequent impact on the deposition profile through convection is examined. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Electrodeposition of Thermoelectric Superlattice Nanowires,

    ADVANCED MATERIALS, Issue 2 2007
    B. Yoo
    Bi2Te3/(Bi0.3Sb0.7)2Te3superlattice thermoelectric nanowires are synthesized by using a template-directed electrodeposition method. Adjustment of the deposition times and potentials enables precise control over the composition and length of each segment of the nanowires. Characterization of the superlattice nanowires by, amongst others, energy dispersive X-ray analysis (see figure) reveals their periodically varying structure. [source]


    Electrodeposition of Titania Thin Films on Metallic Surface for High- k Dielectric Applications

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2010
    Biplab K. Roy
    Current microelectronics devices based on flexible as well as rigid substrates demand high dielectric constant (k) films to be grown on conductive substrate from a low-cost, low-temperature deposition technique. In this study, we produced high- k titania (TiO2) films through an affordable electrodeposition protocol from the electrochemical bath maintained at about 0°C. The deposition occurs through a rapid hydrolysis mechanism of titanium containing ions in the precursor solution aided by electrochemically generated hydroxyl ions formed near the cathode surface (copper (Cu) substrate). Upon attaining a sufficient supersaturation level, such hydrolyzed species precipitate to form a titania thin film on the cathode surface. While depositing from a highly acidic precursor solution, Cu substrate was protected by a cathodic potential (,3 to ,5 V against the counter electrode). The resultant titania films show nanoparticulate structures evolved from nucleation and growth events of the in situ precipitated particles. Much higher deposition rate (about 1 ,m/min) was observed compared with that of typical chemical bath deposition. The resultant films with a thickness of 1500 nm grown on Cu exhibit very high dielectric properties (e.g., k,30, capacitance density >110 nF/in.2 at 100 kHz) and moderate breakdown voltage (VB) (,17.5 V). These properties indicate the potential of electrodeposited titania films to be used as a small-area thin-film capacitor for miniaturized electronic devices. [source]


    Chitosan Biotinylation and Electrodeposition for Selective Protein Assembly

    MACROMOLECULAR BIOSCIENCE, Issue 5 2008
    Xiao-Wen Shi
    Abstract An alternative route to protein assembly at surfaces based on using the unique capabilities of biological materials for the spatially selective assembly of proteins is described. Specifically, the stimuli-responsive properties of aminopolysaccharide chitosan are combined with the molecular-recognition capabilities of biotin-streptavidin binding. Biotinylated chitosan retains its stimuli-responsive properties and is capable of electrodepositing at specific electrode addresses. Once deposited, it is capable of binding streptavidin, which can mediate the subsequent assembly of biotinylated proteins. Spatially selective protein assembly using biotinylated Protein A and fluorescently-labeled antibodies is demonstrated. [source]


    Electrodeposition study of ODN:SWCNT hybrids on gold substrates

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2008
    Roya R. Lahiji
    Abstract Sonication of short single-stranded DNA (oligodeoxyribonucleotide; ODN) with Single-Walled Carbon Nanotubes (SWCNTs) greatly facilitates the dispersion of SWCNTs from entangled ropes in an aqueous solution, creating ODN:SWCNT hybrids. Electrodeposition has been investigated to determine if well-dispersed ODN:SWCNT hybrids on a metal substrate can be created. Preliminary studies indicate that electrodeposition using an Au substrate held at +0.5 V produces ODN:SWCNT hybrids that are uniformly deposited across the Au substrate. This result can be compared to samples produced by drop casting and evaporation techniques which yield a thick tangled mat of ODN:SWCNT hybrids across the substrate. The resulting electrodeposited samples were characterized using Scanning Probe Microscope (SPM) and X-ray Photoemission Spectroscopy (XPS) techniques. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    Lithographically patterned nanowire electrodeposition

    PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2008
    Chengxiang Xiang
    Abstract Lithographically Patterned Nanowire Electrodeposition (LPNE) is a new nanofabrication technique in which photolithography is used to define the position of electrodeposited nanowires on the surface of a dielectric such as glass or oxidized silicon. In LPNE, a resist-covered nickel film with a thickness of beween 6 and 100 nm is photopatterned. After development of the resist, the exposed nickel is dissolved in nitric acid under conditions that produce an "undercut" at the resist edges. This undercut functions as a horizontal trench into which metals (e.g., Au, Pt, Pd) can be electrodeposited using the exposed nickel edge present within this trench. As this trench is filled during electrodeposition, a nanowire with a precisely defined height and width is formed along the entire perimeter of the photoresist. LPNE nanowires can have minimum dimensions of 6 nm (h) x 20 nm (w) and lengths of more than 1 cm. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    Aqueous CTAB-Assisted Electrodeposition of Gold Atomic Clusters and Their Oxygen Reduction Electrocatalytic Activity in Acid Solutions,

    ANGEWANDTE CHEMIE, Issue 16 2010
    Chinnaiah Jeyabharathi
    Ein großer Fortschritt: Elektrochemisch synthetisierte, tensidstabilisierte Goldcluster (AuACs; Aun, 5,n,13) katalysieren die elektrochemische Reduktion von Sauerstoff (ORR) in saurer Lösung bei geringen Überpotentialen. Abhängig von der Tensidkonzentration wechselt der Mechanismus der ORR allmählich von einem Vier- zu einem Zweielektronenpfad (siehe Bild; SHE=Standard-Wasserstoffelektrode). Demzufolge verschmelzen die Cluster zu Nanopartikeln. [source]


    Electrodeposition of Antimony Telluride.

    CHEMINFORM, Issue 2 2003
    Gisbert Leimkuehler
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Preparation and Characterization of Cu-Doped p-CdTe Films Grown by Cathodic Electrodeposition.

    CHEMINFORM, Issue 38 2002
    Makoto Takahashi
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Fabrication of Nanoelectrodes and Metal Clusters by Electrodeposition

    CHEMPHYSCHEM, Issue 13 2010
    Jeyavel Velmurugan
    Abstract Most nanometer-sized electrodes reported to date are made from either Pt or Au. For technical reasons, it is difficult to make nanoelectrodes from many other metals (e.g. Hg) by heat-sealing microwires into glass capillaries or by other established techniques. Such nanoelectrodes can be useful for a wide range of analytical and physicochemical applications from high sensitivity stripping analysis (Hg) to pH nano-sensors to studies of electrocatalysis. In this paper, nanometer-sized metal electrodes are prepared by electrodeposition of Hg or Pt on disk-type, polished or recessed nanoelectrodes. The deposition of Hg is monitored chronoamperometrically to produce near-hemispherical electrodes, which are characterized by voltammetry and scanning electrochemical microscopy (SECM). The well-shaped deposits of a solid metal (Pt) at Au nanoelectrodes are prepared and imaged by scanning electron microscopy (SEM). Catalytic metal clusters can also be prepared using this methodology. Electrodes with the metal surface flush with glass insulator, most suitable for quantitative voltammetric and SECM experiments are fabricated by electrodeposition of a metal inside an etched nanocavity. [source]


    Electrodeposition of Metals and Semiconductors in Air- and Water-Stable Ionic Liquids

    CHEMPHYSCHEM, Issue 1 2006
    Sherif Zein El Abedin Prof. Dr.
    Abstract In addition to their stability, the advantages of air- and water-stable ionic liquids over chloroaluminate ionic liquids, which were intensively investigated in the past, are that they are easy to dry, purify, and handle. Moreover, some of these ionic liquids have an extremely large electrochemical window of more than 5 V, and hence they give access to the electrodeposition of many metals and semiconductors, such as Ta, Ti, Si, and Ge. The results to date for the electrodeposition of metals and semiconductors in the most popular air- and water-stable ionic liquids are presented. [source]


    Electrodeposition, Structure and Corrosion Resistance of Nanocrystalline Ni-W Alloy

    CHINESE JOURNAL OF CHEMISTRY, Issue 3 2004
    Fang-Zu Yang
    Abstract Ni,W alloy was electrodeposited from the electrolyte solution containing sodium tungstate, nickel sulfate and ammonium citrate. The electrodeposition, heat treatment, structure, surface morphology and corrosion resistance in w=0.03 NaCl solution, of Ni,W alloys were studied by means of DSC, XRD, SEM and electrochemical techniques. The results showed that the obtained Ni,W alloy electrodeposit with W weight content (ww=0.471) was presented in more typical nanocrystalline. After heat treatment at 400 C for 1 h, the phase structure of the deposits was not obviously changed whereas the agglomerate for the reunion of tiny grains on deposit surface caused the granule in a more smooth morphology, the microhardness was slightly increased and the corrosion resistance was enhanced. [source]


    Fabrication of Nanoporous Copper Film for Electrochemical Detection of Glucose

    ELECTROANALYSIS, Issue 21 2009
    Sirilak Sattayasamitsathit
    Abstract A nanoporous copper film was fabricated on a copper wire by electrodeposition of copper/zinc alloy and chemically etching of zinc. The surface morphology was investigated by SEM. When applied to detect glucose in an amperometric flow injection system the porous copper electrode provided 12 times higher sensitivity than solid copper. It could be continuously used up to 50 times (%RSD=5.7). Different preparations of the porous film provided reproducible responses (P<0.05). Detection of glucose in E. coli cultivation medium compared well with spectrophotometric technique (P<0.05). This simple technique can produce a nanoporous electrode with good performances and can easily be applied to other metals and analytes. [source]


    Disposable Gold Electrode Array for Simultaneous Electrochemical Studies

    ELECTROANALYSIS, Issue 1 2008
    Graciela Priano
    Abstract An efficient and inexpensive eight gold electrode array has been manufactured by a combination of screen printing and gold electrodeposition techniques. Gold electrodeposition was performed in potentiostatic and galvanostatic conditions. Different treatments, involving temperature and polishing control, led to electrodes with different roughness. The electrochemical behavior of the generated gold surface was studied by cyclic voltammetry showing the characteristic response of polycrystalline gold, in contrast with disposable gold electrodes fabricated by screen printing from gold inks. The electrodes were chemically modified through the adsorption of alkanethiols self-assembled monolayers and the coupling of a model protein. Both reactions were followed by cyclic voltammetry and Electrochemical Impedance Spectroscopy (EIS). The electrodes have shown high reproducibility in their electrochemical behavior as well as in their modifications. [source]


    Impedance Spectroscopy: A Powerful Tool for Rapid Biomolecular Screening and Cell Culture Monitoring

    ELECTROANALYSIS, Issue 23 2005
    Isaac
    Abstract Dielectric spectroscopy or Electrochemical impedance spectroscopy (EIS) is traditionally used in corrosion monitoring, coatings evaluation, batteries, and electrodeposition and semiconductor characterization. However, in recent years, it is gaining widespread application in biotechnology, tissue engineering, and characterization of biological cells, disease diagnosis and cell culture monitoring. This article discusses the principles and implementation of dielectric spectroscopy in these bioanalytical applications. It provides examples of EIS as label-free, mediator-free strategies for rapid screening of biocompatible surfaces, monitoring pathogenic bacteria, as well as the analysis of heterogeneous systems, especially biological cells and tissues. Descriptions are given of the application of nanoparticles to improve the analytical sensitivities in EIS. Specific examples are given of the detection of base pair mismatches in the DNA sequence of Hepatitis B disease, TaySach's disease and Microcystis spp. Others include the EIS detection of viable pathogenic bacteria and the influence of nanomaterials in enhancing biosensor performance. Expanding applications in tissue engineering such as adsorption of proteins onto thiolated hexa(ethylene glycol)-terminated (EG6) self-assembled monolayer (SAM) are discussed. [source]


    Catalytic Effect on Silver Electrodeposition of Gold Deposited on Carbon Electrodes

    ELECTROANALYSIS, Issue 19 2004
    Alfredo de, Escosura-Muñiz
    Abstract A new methodology, based on silver electrocatalytic deposition and designed to quantify gold deposited onto carbon paste electrode (CPE) and glassy carbon electrode (GCE), has been developed in this work. Silver (prepared in 1.0,M NH3) electrodeposition at ,0.13,V occurs only when gold is previously deposited at an adequate potential on the electrode surface for a fixed period of time. When a CPE is used as working electrode, an adequate oxidation of gold is necessary. This oxidation is carried out in both 0.1,M NaOH and 0.1,M H2SO4 at oxidation potentials. When a GCE is used as working electrode, the oxidation steps are not necessary. Moreover, a cleaning step in KCN, which removes gold from electrode surface, is included. To obtain reproducibility in the analytical signal, the surface of the electrodes must be suitably pretreated; this electrodic pretreatment depends on the kind of electrode used as working electrode. Low detection limits (5.0×10,10,M) for short gold deposition times (10,min for CPE and 5,min for GCE) were achieved with this novel methodology. Finally, sodium aurothiomalate can be quantified using silver electrocatalytic deposition and GCE as working electrode. Good linear relationship between silver anodic stripping peak and aurothiomalate concentration was found from 5.0×10,10,M to 1.0×10,8,M. [source]


    Investigation of the Effect of Different Glassy Carbon Materials on the Performance of Prussian Blue Based Sensors for Hydrogen Peroxide

    ELECTROANALYSIS, Issue 3 2003
    Francesco Ricci
    Abstract Three different kinds of glassy carbon (GC-R, GC-K, GC-G) were equally pretreated, further modified with electrochemically deposited Prussian Blue and used as sensors for hydrogen peroxide at an applied potential of ,50,mV (vs. Ag|AgCl). Their performance was evaluated with respect to the following parameters: the coverage and electrochemistry of the electrodeposited Prussian Blue, the sensitivity and the lower limit of detection for hydrogen peroxide, and the operational stability of the sensors. GC-R showed the best behavior concerning the surface coverage and the operational stability of the electrodeposited Prussian Blue. For this electrode the sensitivity for hydrogen peroxide (10,,M) was 0.25,A/M cm2 and the detection limit was 0.1,,M. Scanning electron microscopy was used to study the surfaces of the three electrodes before and after the electrodeposition of Prussian Blue and to search for the reason for the three different behaviors between the different glassy carbon materials. The Prussian Blue modified GC-R was also used for the construction of a glucose biosensor based on immobilizing glucose oxidase in Nafion membranes on top of electrodeposited Prussian Blue layer. The operational stability of the glucose biosensors was studied in the flow injection mode at an applied potential of ,50,mV (vs. Ag|AgCl) and alternatively injecting standard solutions of hydrogen peroxide (10,,M) and glucose (1,mM) for 3,h. For the GC-R based biosensor a 2.8% decrease of the initial glucose response was observed. [source]


    Elaboration of Monophasic and Biphasic Calcium Phosphate Coatings on Ti6Al4V Substrate by Pulsed Electrodeposition Current

    ADVANCED ENGINEERING MATERIALS, Issue 6 2010
    Hicham Benhayoune
    Calcium phosphate coatings on Ti6Al4V substrates are elaborated by pulsed electrodeposition. The surface morphology and chemical composition of the coatings are characterized by SEM,EDS. The obtained results are systematically confirmed at the nanometre scale using TEM. Moreover, XRD is performed in order to identify the coatings phases. The results show that pulsed electrodeposition allows uniform coatings to be obtained without the holes and craters usually observed with classical electrodeposition. After appropriate heat treatment, these coatings have a biphasic composition of stoichiometric hydroxyapatite and , -tricalcium phosphate. Moreover, the addition of 9% H2O2 to the electrolyte leads to monophasic coatings made of stoichiometric hydroxyapatite. As an indication of the passive nature of the electrodeposited coating, electrochemical potentiodynamic tests are performed in physiological solution in order to determine the corrosion behaviour of these coatings. [source]


    The Optimal Grain Sized Nanocrystalline Ni with High Strength and Good Ductility Fabricated by a Direct Current Electrodeposition,

    ADVANCED ENGINEERING MATERIALS, Issue 6 2008
    X. Shen
    In this work, six pure Ni specimen which mean grain sizes spans a broad range from ultra-fine to nanometer were fabricated by direct current electrodeposition and a coarse grain Ni was obtained by annealing. A gradual transition of the crystallographic preferred orientation of the deposited Ni from (200) texture to isotropic or random orientation with decreasing the mean grain size was revealed by XRD. [source]