Search for: manganese-alloys
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    Electrodeposition and Characterization of Zn-Ni-Mn Coatings

    , M.Sc. Thesis Sharif University of Technology Esmaeeli, Mehdi (Author) ; Ghorbani, Mohammad (Supervisor)
    In this study, the electrochemical precipitation of three-component zinc-nickel-manganese coating on st37 steel substrate from chloride bath was investigated. Cyclic voltammetry results showed that the presence of ammonium thiocyanate complexer had a positive effect on the stability of precipitated manganese. Also, in order to evaluate the optimal coating conditions, the precipitation process at voltages of -1.4, -1.5 and VSCE -6.6, concentration of zinc 0.3 M, concentration of nickel 0.15 M and concentrations of manganese 0.15, 0.3 And 0.45 M and temperatures of 25, 40 and 55 .C. The results of X-ray energy diffraction spectroscopy, atomic absorption spectroscopy and X-ray diffraction of... 

    Characterization of nanostructured biodegradable Zn-Mn alloy synthesized by mechanical alloying

    , Article Journal of Alloys and Compounds ; Volume 735 , 2018 , Pages 1319-1327 ; 09258388 (ISSN) Sotoudeh Bagha, P ; Khaleghpanah, S ; Sheibani, S ; Khakbiz, M ; Zakeri, A ; Sharif University of Technology
    Elsevier Ltd  2018
    In this study, nanostructured biodegradable pure Zn, Zn-4 wt. % Mn and Zn-24 wt % Mn alloys were produced by 20 h mechanical alloying and consequent cold pressing and sintering. Structural evolutions were investigated using the X-ray diffraction technique. Also, the microstructure was characterized by scanning electron microscopy. The effects of alloy composition on density, mechanical properties, corrosion behavior in Hank's solution, cell viability and cell attachment were investigated. Crystallite size of the synthesized alloys after 20 h of milling reached to less than 40 nm and remained less than 80 nm after consolidation and sintering for 1 h. Alloys contain MnZn13 as second phase... 

    Effects of lithium excess and Ni content on the electrochemical performance of Li1+x (Ni0.45-xMn0.4Co0.15) O2 lithium-ion cathode materials in stoichiometric state

    , Article Materials Research Express ; Volume 6, Issue 8 , 2019 ; 20531591 (ISSN) Tolouei, A ; Kaflou, A ; Sadrnezaad, S. K ; Sharif University of Technology
    Institute of Physics Publishing  2019
    In Li-ion batteries, application of active materials can enhance the kinetics of the charge-discharge process, reduce the costs and improve the safety of the system. In this work, the effect of nickel content and lithium excess in Li1+x (Ni0.4-xMn0.5Co0.1) O2 compounds on the electrochemical performance of the lithium-ion battery cathode have been studies. For this purpose, three compounds of NMC in the stoichiometric state were synthesized via co-precipitation as the cathode active material. XRF and EDS analyses indicate that precursors and oxide compounds are well synthesized. The final compound of synthesized cathodes was obtained by ICP analysis. XRD results also suggest that the... 

    Acoustic energy harvesting via magnetic shape memory alloys

    , Article Journal of Physics D: Applied Physics ; Volume 52, Issue 13 , 2019 ; 00223727 (ISSN) Askari Farsangi, M. A ; Zohoor, H ; Sharif University of Technology
    Institute of Physics Publishing  2019
    This study investigates acoustic energy harvesting via magnetic shape memory alloys (MSMA). The acoustic pressure impacts the neck of a Helmholtz resonator (HR) with a flexible face made of an elastic membrane. The design of the proposed energy harvester let radial force in the membrane be tunable. An MSMA is clamped to the membrane, and a proof mass is attached to the other end. The enhanced sound pressure vibrates the membrane and, therefore, excites the base of the MSMA specimen made of Ni-Mn-Ga to apply strain to it. Inserting strain onto the MSMA leads to variant reorientation and change of magnetization vectors, resulting in a change in flux passing through the pick-up coil. Therefore,... 

    Cell-structure and flow stress investigation of largely strained non-heat-treatable Al-alloys using dislocation based model

    , Article Materials Science and Engineering A ; Volume 739 , 2019 , Pages 167-172 ; 09215093 (ISSN) Firouzabadi, S. S ; Kazeminezhad, M ; Sharif University of Technology
    Elsevier Ltd  2019
    A severe plastic deformation is widely used to improve the mechanical properties of non-heat-treatable alloys. Thus, the investigation and modeling of microstructural evolutions of materials during large straining are of great importance. In this research, substructural evolutions of four different kinds of Al alloys namely Al-1Mn, Al-1Mg, Al-2.77Mg and Al-5Mg, have been studied using a dislocation based model and the mechanical properties of these alloys have been compared considering all microstructural parameters such as dislocation density, subgrain size, cell wall misorientation and the effect of alloying element. As a result, a simplified general equation has been expressed in order to... 

    Oxidation behavior and electrical properties of de-siliconized aisi 430 alloy with mn1.5co1.5o4 coating for solid oxide fuel cell interconnect

    , Article Oxidation of Metals ; Volume 93, Issue 3-4 , 2020 , Pages 401-415 Bakhshi Zadeh, A ; Salmani, S ; Faghihi Sani, M. A ; Abdoli, H ; Jalili, N ; Sharif University of Technology
    Springer  2020
    Abstract: The effect of de-siliconization on the oxidation behavior of AISI 430 stainless steel used for solid oxide fuel cell interconnect application was investigated. De-siliconization treatment was conducted via heating steel parts in an H2 environment. The de-siliconized substrates were then coated with a Mn1.5Co1.5O4 spinel coating, using wet spray method. For comparison, a similar coating process was applied on the as-received AISI 430 stainless steel specimens. Oxidation kinetics of coated interconnects were evaluated at 700, 800 and 900 °C in air. Results showed that the de-siliconization surface treatment decreased oxidation rates, with kinetic rates (g2 cm−4 s−1) of 4.39 × 10−14... 

    Microstructure and mechanical properties of pure Cu interlayer TLP joints of 304 stainless steel to dual phase steel

    , Article Journal of Materials Processing Technology ; Volume 275 , January , 2020 Mohammadi, M ; Ekrami, A ; Sharif University of Technology
    Elsevier Ltd  2020
    Bonding was carried out at 1150 °C for holding times of 60 and 90 min followed by water quenching. At the bonding time of 60 min, Cu remained at the bond region resulting in an unstable liquid/solid interface with a sinusoidal microstructure. Isothermal solidification completed at the holding time of 90 min. Unidirectional solidification was observed from the stainless steel side toward the low carbon manganese steel and abnormal grain growth of stainless steel was seen at the bond region due to temperature gradient which originated from different electrical properties of the parent alloys. Joints made at the bonding time of 90 min were homogenized at 730 °C for 75 min and quenched in water... 

    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... 

    Effect of drying conditions on the catalytic performance, structure, and reaction rates over the Fe-Co-Mn/MgO catalyst for production of light olefins

    , Article Bulletin of Chemical Reaction Engineering & Catalysis ; Volume 13, Issue 1 , 2018 , Pages 97-112 ; 19782993 (ISSN) Abdouss, M ; Arsalanfar, M ; Mirzaei, N ; Zamani, Y ; Sharif University of Technology
    Diponegoro University  2018
    The MgO-supported Fe-Co-Mn catalysts, prepared using co-precipitation procedure, were tested for production of light olefins via CO hydrogenation reaction. The effect of a range of drying conditions including drying temperature and drying time on the structure and catalytic performance of Fe-Co-Mn/MgO catalyst for Fischer-Tropsch synthesis was investigated in a fixed bed micro-reactor under the same operational conditions of T = 350 °C, P = 1 bar, H2/CO = 2/1, and GHSV = 4500 h-1. It was found that the catalyst dried at 120 °C for 16 h has shown the best catalytic performance for CO hydrogenation. Furthermore, the effect of drying conditions on different surface reaction rates was also...