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    Electrochemical Deposition of Composite Coatings of Nickel - Silicon Carbide Under Pulsed Current Using a Rotating Disk Electrode

    , M.Sc. Thesis Sharif University of Technology Zarghami, Vahid (Author) ; Ghorbani, Mohammad (Supervisor)
    Ni-SiC composite coatings are widely used in industry (equipment high wear resistance coatings, corrosion resistant coatings, ship and boiler coatings, . . . ). Its unique properties in high wear resistance, corrosion resistance and tribological properties, researchers tend to investigate this coating. This study covers Ni-SiC composite coating under pulsed current using a rotating disk electrode to achieve optimal conditions in synthsis process, increaseing hardness and resistance to corrosion in coatings.waats' bath established for electrodeposition in this research. Bath parameters, current parameters and hydrodynamic of solution is examined. Changing of current type from direct current... 

    Study of the effect of fluid flow on corrosion rate for simple carbon steel in aqueous solution using rotating disk electrode

    , Article 18th International Congress of Chemical and Process Engineering, CHISA 2008, Prague, 24 August 2008 through 28 August 2008 ; 2008 Bastani, D ; Mohagheghi, A ; Sharif University of Technology
    The influence of fluid flow on the corrosion of simple carbon steel ST37 (AISI 1020) in aqueous solution of Bandar-Abbas gas well was studied at 25°C under air-saturated condition. The mechanism and kinetic of corrosion in different hydrodynamic conditions were determined using a rotating disk electrode. Increasing the velocity of rotating disk ≤ 1000 rpm caused an augmentation in corrosion rate from 9.89 to 18.95 mill in./yr. Increasing the velocity beyond 1000 rpm changed the corrosion mechanism so that the activation polarization will control the corrosion process, and the variation in corrosion rates was due to various corrosion mechanisms rather than mass transfer of reactant component.... 

    Alteration of corrosion and nanomechanical properties of pulse electrodeposited Ni/SiC nanocomposite coatings

    , Article Journal of Alloys and Compounds ; Vol. 598 , 2014 , Pages 236-242 ; ISSN: 09258388 Zarghami, V ; Ghorbani, M ; Sharif University of Technology
    Nickel/silicon carbide composite electrodeposits were prepared on a rotating disk electrode (RDE), under pulse current condition. The effect of pulse parameters, current density, SiC content in the electrolyte on the codeposition of SiC were studied. Afterwards, the effect of codeposited SiC amount was investigated on electrochemical behavior and nanomechanical properties of coatings. The coatings were analyzed with Scanning Electron Microscopy (SEM), linear polarization, nanoindentation and Atomic Force Microscopy (AFM). The Ni-SiC electrocomposites, prepared at optimum conditions, exhibited improved nanomechanical properties in comparison to pure nickel electrodeposits. With increasing... 

    Kinetic studies of glucose electrocatalytic oxidation on GC/Ni electrode

    , Article International Journal of Chemical Kinetics ; Volume 44, Issue 11 , 2012 , Pages 712-721 ; 05388066 (ISSN) Danaee, I ; Jafarian, M ; Forouzandeh, F ; Gobal, F ; Sharif University of Technology
    Nickel-modified glassy carbon electrode (GC/Ni) prepared by galvanostatic deposition was used for the electrocatalytic oxidation of glucose in alkaline solutions where different electrochemical methods were employed. In cyclic voltammetry studies, in the presence of glucose an increase in the peak current of the oxidation of nickel hydroxide is followed by a decrease in the corresponding cathodic current. This suggests that the oxidation of glucose is being catalyzed through mediated electron transfer across the nickel hydroxide layer comprising nickel ions of various valence states. Under the chronoamperometric regime, the reaction followed a Cottrellian behavior and the diffusion... 

    Electrochemical oxidation of saccharose on copper (hydr)oxide-modified electrode in alkaline media

    , Article Cuihua Xuebao/Chinese Journal of Catalysis ; Volume 31, Issue 11 , 2010 , Pages 1351-1357 ; 02539837 (ISSN) Jafarian, M ; Rashvand Avei, M ; Danaee, I ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    A stable copper (hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of -250 to 1000 mV. It can be used for electrochemical studies in the range of -250 to 1000 mV without interfering peaks because there is no oxidation of copper. During an anodic potential sweep, the electro-oxidation of saccharose on Cu occurred by the formation of CuIII and this reaction also occurred in the early stages of the reversed cycle until it is stopped by the negative potentials. A mechanism based on the electro-chemical generation of CuIII active sites and their subsequent consumption by saccharose was proposed, and the rate law and kinetic parameters were... 

    A preliminary study of the electro-catalytic reduction of oxygen on Cu-Pd alloys in alkaline solution

    , Article Journal of Electroanalytical Chemistry ; Volume 647, Issue 1 , 2010 , Pages 66-73 ; 15726657 (ISSN) Gobal, F ; Arab, R ; Sharif University of Technology
    Copper-palladium alloys of different compositions are electrodeposited on nickel from aqueous solutions. These alloys are characterized by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The catalytic activity of these alloys toward oxygen reduction reaction (ORR) in alkaline solution is investigated using rotating disk electrode (RDE). The number of electrons transferred per O2 molecule (n) obtained at different potentials is close to 2 at low overpotential indicating HO2- formation and gradually increases to 4 at higher overpotentials indicating full reduction to OH-. It is shown that Cu-Pd alloys are better electrocatalysts than Pd with Pd-Cu-1 having 24.5%... 

    Preparation of new titanium nitride-carbon nanocomposites in supercritical benzene and their oxygen reduction activity in alkaline medium

    , Article Electrochimica Acta ; Volume 164 , May , 2015 , Pages 114-124 ; 00134686 (ISSN) Yousefi, E ; Ghorbani, M ; Dolati, A ; Yashiro, H ; Outokesh, M ; Sharif University of Technology
    Elsevier Ltd  2015
    Titanium nitride-carbon nanocomposites are synthesized by the reaction of TiCl4 and NaN3 in supercritical benzene medium that also serves as a carbon source. The as-prepared precursors (SI, SII) are subjected to several heat treatments (SIII-SV). The synthesized nanoparticles are characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The samples are tested as electrocatalyst for oxygen reduction reaction in an alkaline electrolyte. It is shown that the electrocatalytic properties of the synthesized nanoparticles are...