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    Study of Nanocrystallization Kinetics, Microstructure and Magnetic Properties of Finemet-type Soft Magnetic Materials

    , Ph.D. Dissertation Sharif University of Technology Asghari Shivaee, Hossein (Author) ; Madaah Hosseini, Hamid Reza (Supervisor) ; nozad, Ahmad (Supervisor) ; Beitollahi, Ali (Co-Advisor)
    Nanocrystallization kinetics of amorphous Finemet-type alloys was studied using Isokinetic and Isoconversional methods (Kissinger model-fitting method, Vyazovkin advance method, Kissinger–Akahira–Sunose(KSA),Flynn–Wall–Ozawa(FWO),Tang and Starink) under isothermal and non-isothermal conditions. Effects of chemical composition on the nanocrystallization kinetics, microstructure and magnetic properties of Fe73.5Si13.5B9Nb3Cu1 and Fe77Si11B9Nb2.4Cu0.6 alloys were also investigated. Kinetic triplet (activation energy, frequency factor and reaction model) were determined by these methods and compared for the alloys. According to isoconversional methods, the activation energy is variable as a... 

    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... 

    Constructing and Investigation of the Electrochemical Behavior of Nanocomposite of Conducting Polymers on Copper Hydroxide Nanotubes; Application to Determination of Glucose

    , M.Sc. Thesis Sharif University of Technology Manafi, Reza (Author) ; Shahrokhian, Saeed (Supervisor)
    A novel amperometric non-enzymatic glucose (NEG) sensor is designed by a facile preparation method. It is made by electrodeposition of Cu clusters and converting them to Cu(OH)2 nanotubes (Cu(OH)2NTs) arrays along with thin-film electro-polymerized of spindle-shaped polypyrrole (PPy@Cu(OH)2NTs), which have been doped by using sodium Benzene-1,3- disulfonate as an anion dopant. The electrochemical performance of the modified electrode toward glucose detection is investigated by various electrochemical methods. Under the optimized conditions, a significant electrochemical response improvement is observed toward the electro-oxidation of glucose on the surface of PPy@Cu(OH)2NTs electrode... 

    Modification of well-aligned carbon nanotubes with dihexadecyl hydrogen phosphate: Application to highly sensitive nanomolar detection of simvastatin

    , Article Journal of Applied Electrochemistry ; Volume 44, Issue 2 , February , 2014 , Pages 263-277 ; ISSN: 0021891X Fayazfar, H ; Afshar, A ; Dolati, A ; Ghalkhani, M ; Sharif University of Technology
    The first usage of dihexadecyl hydrogen phosphate (DHP)-modified highly oriented multi-walled carbon nanotube (MWCNTs) forests in a sensor configuration was developed to investigate the electrochemical oxidation and determination of simvastatin (SV) in pharmaceutical dosage forms. Synthesis of well-aligned MWCNTs on a conductive Ta substrate by catalytic vapor deposition technique using a common chemical, ethylenediamine, and without being plasma-aided was reported. The electrochemical behavior and oxidation of SV at the aligned MWCNTs/DHP/Ta electrode were discussed in detail through cyclic voltammetry and differential pulse voltammetry. This modified electrode showed considerably higher... 

    Electrochemical behavior of S-doped nanostructured TiO2 layer synthesized with PEO process for photocatalytic applications

    , Article Advanced Materials Research ; Volume 829 , 2014 , Pages 487-491 ; ISSN: 10226680 ; ISBN: 9783037859070 Ahmadzadeh, M ; Ghorbani, M ; Sharif University of Technology
    Sulfur doped and pure micro-nanoporous TiO2 film were synthesized with PEO method to produce a film with a high surface area for photocatalysis applications. The effect of applied voltage and electrolyte concentration on the microstructure and photocatalytic properties of the prepared layer were investigated via SEM, XRD, EIS and DRS studies. Electrochemical Impedance Spectroscopy (EIS) was carried out in order to determine the corrosion and electrochemical properties of the produced layer. It was found that although the barrier layer resistance decreases with the voltage, the layers porosity and consequently the surface area increases. Finally the XRD and DRS spectrums were correlated with... 

    Highly sensitive 3D gold nanotube ensembles: Application to electrochemical determination of metronidazole

    , Article Electrochimica Acta ; Volume 106 , 2013 , Pages 288-292 ; 00134686 (ISSN) Mollamahale, Y. B ; Ghorbani, M ; Ghalkhani, M ; Vossoughi, M ; Dolati, A ; Sharif University of Technology
    Three-dimensional gold nanoelectrode ensembles (3D GNE) have proven to be promising nanoelectrodes by representing much higher sensitivity compared to both their 2D nanostructures and bulk counterparts. The sensitivity of 3D gold nanotubes (GNTs) fabricated through electrodeposition inside the pores of polycarbonate templates, was examined toward metronidazole (MTZ) as one of their pharmaceutical applications. The electrochemical behavior of MTZ at the 3D GNT-modified electrode was discussed in detail through cyclic voltammetry (CV) which suggested an irreversible reduction of nitro group to the corresponding hydroxylamine and a subsequently reversible redox peak for the corresponding... 

    Adsorptive stripping differential pulse voltammetric determination of mebendazole at a graphene nanosheets and carbon nanospheres/chitosan modified glassy carbon electrode

    , Article Sensors and Actuators, B: Chemical ; Volume 185 , 2013 , Pages 669-674 ; 09254005 (ISSN) Ghalkhani, M ; Shahrokhian, S ; Sharif University of Technology
    For the first time graphene nanosheets and carbon nanospheres/chitosan (GNS-CNS/CS) based nanocomposite film modified electrode was used for the electro-oxidation of mebendazole (MD). MD is a benzimidazole drug that is used to treat human infections caused by parasitic worms. MD causes slow immobilization and death of the worms by selectively and irreversibly blocking uptake of glucose. The electrochemical behavior of MD at GNS-CNS/CS modified glassy carbon electrode has been investigated using cyclic and differential pulse voltammetry in aqueous media at different pHs. The prepared electrode showed an excellent electrochemical activity toward the electro-oxidation of MD leading to a... 

    Effect of Ca2+ additives on morphology, composition and corrosion resistant of Zn-12%Ni phosphate coating

    , Article Journal of Materials Research and Technology ; Volume 5, Issue 4 , 2016 , Pages 327-332 ; 22387854 (ISSN) Alizadeh, H ; Hanaei, A ; Pakseresht, A. H ; Shahbazkhan, A ; Parvini Ahmadi, N ; Baniasadi, F ; Sharif University of Technology
    Elsevier Editora Ltd 
    The aim of this study is to investigate the effect of phosphate solution with Ca2+ additives on weight, surface morphology and electrochemical behavior of phosphated Zn-Ni film. In order to characterize structure and morphology of surface, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied, respectively. Results showed that the main composition in produced coatings was hopeite Zn3(PO4)2·4H2O, which has high corrosion resistance. On one hand, in the presence of Ca2+ cations in solution, the weight of phosphate coating decreased, but on the other hand surface uniformity and corrosion resistance of the coating increased  

    Structural, microstructural and electrochemical studies of TiO2-Ag double layer coated NCM cathode for lithium-ion batteries

    , Article Materials Research Express ; Volume 6, Issue 8 , 2019 ; 20531591 (ISSN) Sharifi Rad, A ; Ghorbanzadeh, M ; Sharif University of Technology
    Institute of Physics Publishing  2019
    Lithium ion batteries as one of the most important energy storage equipments, have several challenges including capacity drop as number of cycles increases. Cathode particle coating is an effective approach in improvement of electrochemical performance of the batteries. In this study, TiO2-Ag coating was used to improve NCM cathode performance. The microstructure and crystal structure properties of coated NCMs were evaluated by the FE-SEM and XRD. Electrochemical behavior of the batteries was investigated by cycling performance analysis and EIS. TiO2 coating was deposited as a uniform layer and Ag coating was precipitated as dispersed nanoparticles. The results shows that using of TiO2-Ag... 

    Electrochemical deposition of flower-like nickel nanostructures on well-defined n-si(111):h

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 21, Issue 2 , 2008 , Pages 177-182 ; 1728-144X (ISSN) Torabi, M ; Khalifehzadeh, R ; Arami, H ; Sadrnezhaad, S. K ; Sharif University of Technology
    Materials and Energy Research Center  2008
    In this paper the electrodeposition of nickel on n-Si(111):H substrate, in the presence of sulphuric acid, was studied. Cyclic voltammetry has been used to characterize the electrochemical behavior of the system. The nickel deposits had a flower-like morphology with the spherical nanostructure nucleus, distributed uniformly on the surfaces of the prepared n-Si(111) substrate  

    Anodizing behavior and electrochemical evaluation of accumulative roll bonded Al and Al-SiC composite

    , Article Surface and Coatings Technology ; Volume 408 , 2021 ; 02578972 (ISSN) Ebadi, M ; Alishavandi, M ; Paydar, M. H ; Sharif University of Technology
    Elsevier B.V  2021
    Accumulative roll bonded (ARBed) AA1050 and Al-2 vol% SiCp (AMC) samples were anodized in an H2SO4 electrolyte to improve corrosion resistance. The SEM images revealed that the anodic oxide's morphology is significantly dependent on the microstructure of the ARBed bare samples, owing to high internal energy that accelerates Al consumption during anodizing process. Potentiodynamic polarization measurements and EIS evaluation showed that anodic oxide improves the corrosion resistance of both ARBed AA and AMC samples; however, the electrochemical behavior of the processed samples changed due to the formation of a complex oxide structure comprising of twisted pore channels and attack routes. ©... 

    Corrosion inhibition of mild steel with tolyltriazole

    , Article Materials Research ; Volume 24, Issue 4 , 2021 ; 15161439 (ISSN) Fathabadi, H. E ; Ghorbani, M ; Mokarami Ghartavol, H ; Sharif University of Technology
    Universidade Federal de Sao Carlos  2021
    Tolyltriazole (TTA) is a well-defined corrosion inhibitor for copper and copper alloys. However, there is little literature about its corrosion inhibition performance for mild steels in corrosive environments. This paper studied the electrochemical behavior of TTA in 0.5 M HCl solutions. Also, the morphology and nature of TTA layers on the steel surface were investigated. Electrochemical results showed that TTA is an excellent corrosion inhibitor for mild steel in acidic media with an efficiency of 91% for 0.07 M concentration. The results also indicated that TTA is a mixed-type inhibitor. XRD analysis revealed that the inhibition mechanism of TTA is based on the formation of an organic film... 

    Electrophoretic deposition of bioactive glass coating on 316L stainless steel and electrochemical behavior study

    , Article Applied Surface Science ; Volume 258, Issue 24 , 2012 , Pages 9832-9839 ; 01694332 (ISSN) Mehdipour, M ; Afshar, A ; Mohebali, M ; Sharif University of Technology
    Elsevier  2012
    In this research, submicron bioactive glass (BG) particles were synthesized by a sol-gel process and were then coated on a 316L stainless steel substrate using an electrophoretic deposition (EPD) technique. Stable suspension of bioactive glass powders in ethanol solvent was prepared by addition of triethanol amine (TEA), which increased zeta potential from 16.5 ± 1.6 to 20.3 ± 1.4 (mv). Thickness, structure and electrochemical behavior of the coating were characterized. SEM studies showed that increasing EPD voltage leads to a coating with more agglomerated particles, augmented porosity and micro cracks. The results of Fourier transformed infrared (FTIR) spectroscopy revealed the adsorption... 

    Al2O3/Si3N4 nanocomposite coating on aluminum alloy by the anodizing route: Fabrication, characterization, mechanical properties and electrochemical behavior

    , Article Ceramics International ; 2016 ; 02728842 (ISSN) Mohammadi, I ; Afshar, A ; Ahmadi, S ; Sharif University of Technology
    An Al2O3/Si3N4 nanocomposite coating was successfully fabricated on commercial aluminum alloy. Hardness measurements, polarization and electrochemical impedance spectroscopy (EIS) were employed to study the mechanical and corrosion behaviors of the coatings. Field-Emission Scanning Electron Microscopy (FE-SEM) equipped with Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD) were utilized to characterize the surface morphology and phase composition of the coatings. Also, coatings abrasive wear properties were evaluated with a modified ASTM G105 standard. FE-SEM image, EDS and XRD analysis revealed the presence of Si3N4 in the coating. Furthermore, the results showed hardness of... 

    Chemical modification of the electrode surface by composites of Ag Nanoparticle Decorated on Multi Walled Carbon Nanotube; Application to Investigate the Electrochemical behavior and Determination of Risperidone and Isoxsuprine drugs

    , M.Sc. Thesis Sharif University of Technology Hafezi Kahnamoui, Mohammad (Author) ; Shahrokhian, Saeed (Supervisor)
    Nowadays, electrochemical sensors have numerous benefits, including simplicity,low cost, high selectivity and high sensitivity as an efficient and useful tool in various fields such as the environment, disease diagnostics, medical and medical surveillance, and Anti-terrorism security systems have become the focus of attention in the field of analytical measurements. In the meantime, carbon nanostructures and metal nanoparticles have been considered as suitable alternatives in order to improve their surface properties due to their unique electronic properties and mechanical and chemical stability. Since the determination of trace amounts of pharmaceutical and biological compounds is very... 

    Fabrication of an electrochemical sensor based on the electrodeposition of Pt nanoparticles on multiwalled carbon nanotubes film for voltammetric determination of ceftriaxone in the presence of lidocaine, assisted by factorial-based response-surface methodology

    , Article Journal of Solid State Electrochemistry ; Vol. 18, issue. 1 , 2014 , p. 77-88 Shahrokhian, S ; Hosseini-Nassab, N ; Kamalzadeh, Z ; Sharif University of Technology
    A glassy carbon electrode (GCE) is modified with platinum nanoparticle (PtNPs) decorated multiwalled carbon nanotube (MWCNT). The modified electrode is applied for the determination of ceftriaxone (CFX) in the presence of lidocaine. Different methods were used to characterize the surface morphology of the modified electrode. The electrochemical behavior of CFX was investigated at GCE, MWCNT/GCE and PtNPs/MWCNT/GCE. A factorial-based response-surface methodology was used to find out the optimum conditions with minimum number of experiments. Under the optimized conditions, oxidation peak currents increased linearly with CFX concentration in the range of 0.01-10.00 μM with a detection limit of... 

    Advanced gel polymer electrolyte for lithium-ion polymer batteries

    , Article ASME 2013 7th Int. Conf. on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 11th Int. Conf. on Fuel Cell Science, Engineering and Technology ; July , 2013 ; 9780791855515 (ISBN) Zhang, R ; Hashemi, N ; Ashuri, M ; Montazami, R ; Advanced Energy Systems Division, Solar Energy Division ; Sharif University of Technology
    We report improved performance of Li-ion polymer batteries through advanced gel polymer electrolytes (GPEs). Compared to solid and liquid electrolytes, GPEs are advantageous as they can be fabricated in different shapes and geometries; also ionic properties are significantly superior to that of solid and liquid electrolytes. We have synthetized GPE in form of membranes by trapping ethylene carbonate and propylene carbonate in a composite of polyvinylidene fluoride and N-methylpyrrolidinore. By applying phase-transfer method, we synthetized membranes with micro-pores, which led to higher ionic conductivity. The proposed membrane is to be modified further to have higher capacity, stronger... 

    Construction of a modified carbon paste electrode based on TiO2 nanoparticles for the determination of gallic acid

    , Article Journal of Solid State Electrochemistry ; Volume 17, Issue 1 , 2013 , Pages 157-165 ; 14328488 (ISSN) Tashkhourian, J ; Nami Ana, S. F ; Hashemnia, S ; Hormozi Nezhad, M. R ; Sharif University of Technology
    A modified carbon paste electrode was prepared by incorporating the TiO2 nanoparticles in the carbon paste matrix. The electrochemical behavior of gallic acid (GA) is investigated on the surface of the electrode using cyclic voltammetry and differential pulse voltammetry. The surface morphology of the prepared electrode was characterized using the scanning electron microscopy. The results indicate that the electrochemical response of GA is improved significantly at the modified electrode compared with the unmodified electrode. Furthermore, the capabilities of electron transfer on these two electrodes were also investigated by electrochemical impedance spectroscopy. Under the optimized... 

    Mechanical and electrochemical behaviors of butt-welded high temperature steel pipes

    , Article Engineering Failure Analysis ; 2016 ; 13506307 (ISSN) Daavari, M ; Vanini, S. A. S ; Fereiduni, E ; Rokni, M. H ; Sharif University of Technology
    Elsevier Ltd  2016
    In this study, fatigue, corrosion fatigue and electrochemical behaviors of butt-welded A106-B steel pipes were investigated. These pipes were subjected to mechanical and thermal cyclic stresses due to the internal pressure fluctuations and cooling-heating cycles. Residual stress measurements were carried out for three different depths through the thickness and were correlated to the microstructural observations and microhardness measurements. Results showed that the maximum tensile residual stresses existed at the boundary of weld metal and base metal because of the contraction-expansion effects resulting from phase transformations and cooling rate differences. Fatigue fractures occurred at... 

    The influence of surface nanocrystallization induced by shot peening on corrosion behavior of niti alloy

    , Article Journal of Materials Engineering and Performance ; Volume 24, Issue 8 , August , 2015 , Pages 3093-3099 ; 10599495 (ISSN) Olumi, S ; Sadrnezhaad, S. K ; Atai, M ; Sharif University of Technology
    Springer New York LLC  2015
    Nickel-titanium (NiTi) shape memory alloys have been widely used as implant materials, due to their superior shape memory properties and similar mechanical behavior to bone tissue. The presence of nickel on the surface of nickel-titanium alloy and release of this ion in the body environment will result in some allergic reactions. In current study, we used shot pinning process to produce nanocrystalline nickel-titanium alloy with increased corrosion resistance. Field emission scanning electron microscopy (FE-SEM), x-ray diffraction (XRD) analysis, and atomic force microscopy were employed to investigate the surface features of samples. The quantitative chemical analysis of NiTi and modified...