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    Comparison of isothermal with cyclic oxidation behavior of “Cr-Aluminide” coating on inconel 738LC at 900 °C

    , Article Oxidation of Metals ; Volume 87, Issue 1-2 , 2017 , Pages 57-74 ; 0030770X (ISSN) Salehi Doolabi, M ; Ghasemi, B ; Sadrnezhaad, S. K ; Feizabadi, A ; HabibollahZadeh, A ; Salehi Doolabi, D ; AsadiZarch, M ; Sharif University of Technology
    Springer New York LLC  2017
    A two-step pack cementation technique was used to cover nickel-based IN-738LC superalloy with a Cr-aluminide coating layer. The IN-738LC/Cr-aluminide samples were oxidized at 900 °C for 350 and 700 h, isothermally, and 175 and 350 h, cyclically. Each cycle lasted for 25 h. Effects of the isothermal and the cyclic oxidation on (a) morphology, (b) new-phase formation, (c) weight gain, and (d) oxidation reactions were investigated by scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, and weight gain measurements. From results, it was concluded that the oxygen attack was more severe during the cyclic oxidation than the isothermal procedure. Kinetics of the... 

    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... 

    DFT and experimental study of the host-guest interactions effect on the structure, properties, and electro-catalytic activities of N 2O 2-Ni(II) schiff-base complexes incorporated into zeolite

    , Article Journal of Physical Chemistry C ; Volume 116, Issue 34 , 2012 , Pages 18518-18532 ; 19327447 (ISSN) Jafarian, M ; Rashvand Avei, M ; Khakali, M ; Gobal, F ; Rayati, S ; Mahjani, M. G ; Sharif University of Technology
    Ni II-(N,N′-bis(2,4-dihydroxyacetophenone)-2, 2-dimethylpropandiimine (Ni II{salnptn(4-OH) 2}) complex has been encapsulated within the supercage of zeolite-NaY by reacting Ni 2+-exchanged NaY with the flexible Schiff-base ligand that diffuses into the cavities. The encapsulated complex is characterized by EDX, scanning electron microscopy, powder X-ray diffraction, FT-IR, and cyclic voltammetry studies. Density functional calculation is being carried out on both the free nickel Schiff-base complex and that encapsulated in NaY zeolite to investigate changes in structural parameters, energies of the HOMO and LUMO, and absolute hardness and softness. Electrochemical properties of the NaY... 

    Electrooxidation of methanol on NiMn alloy modified graphite electrode

    , Article Electrochimica Acta ; Volume 55, Issue 6 , 2010 , Pages 2093-2100 ; 00134686 (ISSN) Danaee, I ; Jafarian, M ; Mirzapoor, A ; Gobal, F ; Mahjani, M. G ; Sharif University of Technology
    Nickel and nickel-manganese alloy modified graphite electrodes (G/Ni and G/NiMn) prepared by galvanostatic deposition were examined for their redox process and electrocatalytic activities towards the oxidation of methanol in alkaline solutions. The methods of cyclic voltammetery (CV), chronoamperometry (CA) and impedance spectroscopy (EIS) were employed. In CV studies, in the presence of methanol NiMn alloy modified electrode shows a significantly higher response for methanol oxidation. The peak current of the oxidation of nickel hydroxide increase is followed by a decrease in the corresponding cathodic current in presence of methanol. The anodic peak currents show linear dependency upon the...