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Zn-Ni Electrophosphating on galvanized steel using cathodic and anodic electrochemical methods
, Article Surface and Coatings Technology ; January , 2015 ; 02578972 (ISSN) ; Afshar, A ; Aliabadi, A ; Sharif University of Technology
Elsevier
2015
Abstract
Electrophosphating is the novel method for accelerating the low temperature phosphating bath. This method can be performed as cathodic and anodic treatments. Both of them influence the coating deposition mechanism and therefore coating properties. In this study Zn-Ni electrophosphate coating was applied on galvanized steel using cathodic and anodic electrochemical methods. Microstructure, composition and corrosion resistance of coating were characterized by using a scanning electron microscopy, X-ray diffraction method and potentiodynamic polarization test respectively. The results of this study indicated that, by using cathodic method, compact phosphate coating with high corrosion...
Zn–Ni electrophosphating on galvanized steel using cathodic and anodic electrochemical methods
, Article Surface and Coatings Technology ; Volume 306 , 2016 , Pages 497-505 ; 02578972 (ISSN) ; Afshar, A ; Aliabadi, A ; Sharif University of Technology
Elsevier B.V
2016
Abstract
Electrophosphating is the novel method for accelerating the low temperature phosphating bath. This method can be performed as cathodic and anodic treatments. Both of them influence the coating deposition mechanism and therefore coating properties. In this study Zn–Ni electrophosphate coating was applied on galvanized steel using cathodic and anodic electrochemical methods. Microstructure, composition and corrosion resistance of coating were characterized by using a scanning electron microscopy, X-ray diffraction method and potentiodynamic polarization test respectively. The results of this study indicated that, by using cathodic method, compact phosphate coating with high corrosion...
Investigation of the modification process and morphology of organosilane modified nanoclay
, Article Ceramics - Silikaty ; Volume 53, Issue 4 , 2009 , Pages 254-259 ; 08625468 (ISSN) ; Bazgir, S ; Tamizifar, M ; Nemati, A. L. I ; Arzani, K ; Sharif University of Technology
Abstract
This work deals with the preparation of epoxy-clay nanocomposites. The results show that the mechanical properties of nanocomposites depend on their compatibility, the epoxy resin used and the purity of the nanoclay. The used bentonite was purified and the effects of the organoclay synthesis and various additives on its characteristics were evaluated. X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) were used to analyze the microstructure and the phase composition of the nanoclay. The XRD results revealed that when the modifier addition was increased from 10wt.% to 40 wt.%, the interlayer spacing of the nanoclay increased from 12.43 Å being...
Effect of nanoscaled reinforcement particles on the structural evolution of aluminium powder during mechanical milling
, Article Powder Metallurgy ; Volume 52, Issue 2 , 2009 , Pages 151-157 ; 00325899 (ISSN) ; Kamrani, S ; Simchi, A ; seyed Reihani, M ; Sharif University of Technology
2009
Abstract
This paper presents experimental results on the synthesis of nanostructured aluminium matrix nanocomposite powders by comilling of nanoscaled SiC and Al2O3 particles and micrometric aluminium powder. The effect of the nanometric reinforcement particles on the mechanical milling (MA) process of the soft matrix was studied by scanning electron microscopy, X-ray diffraction (XRD), transmission electron microscopy, laser particle size analyser and standard metallographic techniques. It was found that at the early stage of milling, the nanoparticles are smeared on the surface of the aluminium powder and thus do not significantly contribute in the MA process. As the milling continues, the hard...
A study of mechanical and microstructures properties of autoclaved aerated concrete containing nano-graphene
, Article Journal of Building Engineering ; Volume 43 , 2021 ; 23527102 (ISSN) ; Pachideh, G ; Salimbahrami, S. B ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In recent years, the autoclaved aerated concrete (AAC) has been widely used in the building construction industry, especially for construction of infill walls. However, the AAC suffers from several drawbacks such as low compressive and tensile strength, high water absorption as well as insufficient resistance against impacts. To address such issues, this study evaluates the mechanical properties of the AAC blocks in which, the cement has been replaced with nano-graphene. For this purpose, various replacement ratios (0.2, 0.4, and 0.8) were selected and different tests such as compressive and tensile strength (cylindrical specimens with the size of 10 × 20 cm), impact resistance and water...
Synthesis of PZT Nanotubes by Sol-gel Method Aided by Carbon Nanotubes
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Mohammadi, Mohammad Reza (Supervisor)
Abstract
In this project, synthesis of sol-gel derived Pb(Zr0.52Ti0.48)O3 nanotubes in the form of PZT-CNT hybrid, was accomplished by using multi-walled carbon nanotubes as sacrificial template. Simultaneous thermal analyses proved that the as-derived amorphous material crystallized at a significantly low temperature by a considerably low activation energy. X-ray diffraction and selected area electron diffraction patterns showed that the final crystal structure is tetragonal perovskite. Raman spectroscopy results proved that significant changes happened at the surface of carbon nanotubes which are believed to be due to coating. Electron images supported the deposition of a coating on the surfaces of...
Synthesis, Characterization, Structure Determination and Theoretical Studies of Some New Dimethylglyoxime Cobalt (ΙII) Complexes
, M.Sc. Thesis Sharif University of Technology ; Kia, Reza (Supervisor)
Abstract
In this study, a number of complex cobaloxim complexes [Co(DMG)2LX] in which L= 4-MePy, 3-MePy, 4-bzPy, 3-CNPy, 4-CNPy, tBuPy, styPy, NaphPy synthesized and their structure studied. These complexes were identified by FT-IR and 1H NMR methods as well as their solid state structure studied by X-ray crystallography of single crystals. Gaussian 09 software was used to optimize the geometric structure and obtain the vibrational frequency of cobalt complexes. Charge decomposition Analysis (CDA) and molecular orbital studies were performed using the AOMix 6.88 software. Also, the characterization of σ-donating and П-acceptoring of pyridine ligands in these complexes was investigated using...
Synthesis, Characterization, Crystal Structure Determination and Theoretical Studies of Some new Rhenium(I)-tricarbonyl Complexes with 2,2'-bipyridine and 2,9-dimethylphenanthroline Ligands
, M.Sc. Thesis Sharif University of Technology ; Kia, Reza (Supervisor)
Abstract
The synthesis, characterization, structural and computational studies of mononuclear Re(I) tricarbonyl complexes of 2,2'-bipyridine (2,2′-bpy) and 2,9-dimethylphenanthtroline (2,9-Me2Phen), [Re(CO)3(NN)(X)], where NN=2,2′-bpy,X=Br (1) and X=–ONO (3); NN=2,9-Me2 Phen, X=Br (2) and X= –ONO (4), were reported. The complexes characterized by crystallographic and spectroscopic methods and elemental analyses. In each complex, the Re(I) center showed the distorted octahedral geometry. Single crystal X-ray diffraction data revealed the endo-nitrito (κ1–ONO) coordination in complexes 3 and 4. It has been shown that the replacement of the bromo ligand in complexes 1 and 2, either by AgOTf/NaNO2 in a...
A case study in vapor phase synthesis of Mg-Al alloy nanoparticles by plasma arc evaporation technique
, Article Chemical Engineering Journal ; Volume 259 , 2015 , Pages 918-926 ; 13858947 (ISSN) ; Derakhshan, R ; Mirzaee, O ; Sharif University of Technology
Elsevier
2015
Abstract
Alloy nanoparticles in the Mg-Al system were prepared by plasma arc discharge method from the Mgx to Al (45%
Synthesis and crystal structures of a series of (μ-thiophenolato)(μ-pyrazolato-N,N′) double bridged dipalladium(II) complexes and their application in Mizoroki-Heck reaction as highly efficient catalysts
, Article Inorganica Chimica Acta ; Volume 440 , 2016 , Pages 107-117 ; 00201693 (ISSN) ; Tavakoli, G ; Assoud, A ; Bagherzadeh, M ; Boghaei, D. M ; Sharif University of Technology
Elsevier S. A
Abstract
Three new binucleating S-protected ligand precursors, 2-(N,N-dimethylthiocarbamato)-5-methylisophthalaldehyde di-2′-hydroxy 5′-methylanil (1b), 2-(N,N-dimethylthiocarbamato)-5-tert-butylisophthalaldehyde di-2′-hydroxyanil (2a) and 2-(N,N-dimethylthiocarbamato)-5-tert-butylisophthalaldehyde di-2′-hydroxy 5′-methylanil (2b), have been synthesized. The reaction of these ligand precursors with PdCl2 in the presence of pyrazole under Pd-mediated S-C cleavage yielded a series of binuclear palladium(II) complexes of general formula [LPd2(pz)], where pz is the exogenous bridging pyrazolyl ligand and L3- represents a series of pentadentate thiophenol-based bridging ligands originated from their...
Evaluation of the fractured surface of five endodontic rotary instruments: A metallurgical study
, Article Iranian Endodontic Journal ; Volume 11, Issue 4 , 2016 , Pages 286-292 ; 17357497 (ISSN) ; Khalatbari, M. S ; Meraji, N ; Ghorbanzadeh, A ; Sadri, E ; Sharif University of Technology
Iranian Association of Endodontics
2016
Abstract
Introduction: The aim of this study was to compare several metallurgic properties of Neoniti instrument with four other commonly used endodontic rotary files. Methods and Materials: Neoniti A1 (25/0.08), RaCe (25/0.06), Mtwo (25/0.06), Twisted file (25/0.06) and ProTaper Next X2 (25/0.06) were examined by differential scanning calorimetry (DSC) before and after heat treatment at 500°C. X-ray diffraction (XRD) was also performed on the specimens. Furthermore, scanning electron microscopy (SEM) and x-ray energy-dispersive spectrometric (EDS) analyses were carried out on randomly selected fractured files. Results: In SEM tests, dimpled ruptures, characteristic of ductile fracture, were seen in...
Reactivity of a new aryl cycloplatinated(ii) complex containing rollover 2,2′-bipyridine: N -oxide toward a series of diphosphine ligands
, Article New Journal of Chemistry ; Volume 42, Issue 11 , 2018 , Pages 9159-9167 ; 11440546 (ISSN) ; Babadi Aghakhanpour, R ; Hossein Abadi, M ; Kia, R ; Halvagar, M. R ; Raithby, P. R ; Sharif University of Technology
Abstract
Reaction of the electron-rich complex cis-[Pt(p-Me-C6H4)2(SMe2)2] with 2,2′-bipyridine N-oxide, O-bpy occurred by rollover cyclometalation to afford complex [Pt(O-bpy)(p-Me-C6H4)(SMe2)], 1. The obtained complex was characterized using NMR spectroscopy and its solid state structure was determined by the single crystal X-ray diffraction method. The reaction of 1 with seven diphosphine ligands, 1,1-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), N,N-bis(diphenylphosphino)amine (dppa), 1,2-bis(diphenylphosphino)benzene (dppbz) and 1,1′-bis(diphenylphosphino)ferrocene (dppf), in...
Growth and characterization of sodium-tungsten oxide nanobelts with U-shape cross section
, Article Journal of Crystal Growth ; Volume 310, Issue 4 , 2008 , Pages 824-828 ; 00220248 (ISSN) ; Goudarzi, M ; Akhavan, O ; Moshfegh, A. Z ; Fathipour, M ; Sharif University of Technology
2008
Abstract
A simple method for synthesis of Na0.65WO3 nanobelts by using sodium, as a catalyst, in soda-lime glass substrate was reported. The synthesized product was characterized and analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and ultraviolet-visible spectrophotometery. According to SEM observations, nanobelts with U-shape cross section grew between sodium-tungsten oxide islands. The thickness, width, and length of nanobelts were measured <100 nm, between 300 nm-3 μm and 5-20 μm, respectively. In addition, it was observed that some of the nanobelts were constituted from nanowires. Based on XPS analysis, more than 70% of the film...
Immobilization of TiO2 on perlite granules for photocatalytic degradation of phenol
, Article Applied Catalysis B: Environmental ; Volume 74, Issue 1-2 , 2007 , Pages 53-62 ; 09263373 (ISSN) ; Borghei, M ; Vossoughi, M ; Taghavinia, N ; Sharif University of Technology
2007
Abstract
The photocatalytic degradiation of phenol by nanoTiO2 particles coated on perlite as a new composite nano-catalyst was investigated. Titanium dioxide (Degussa P-25) was immobilized on three different supports (perlite granules, glass plates and steel fiber) by a very simple and inexpensive method. Perlite granules have a porosity of more than 95%, which allows them to stay afloat on water surface. This gives the medium a unique characteristic from the processing point of view, which enables it to get wetted with the polluted solution without requiring any pumping and simultaneously be exposed to the radiation source when coated with the photocatalyst. The photocatalytic activity of prepared...
An investigation on the sintering behavior of high strength Al-Zn-Mg-Cu alloy prepared from elemental powders
, Article 2006 Powder Metallurgy World Congress and Exhibition, PM 2006, Busan, 24 September 2006 through 28 September 2006 ; Volume 534-536, Issue PART 1 , 2007 , Pages 489-492 ; 02555476 (ISSN); 0878494197 (ISBN); 9780878494194 (ISBN) ; Sirnchi, A ; Danninger, H ; Arvand, A ; Sharif University of Technology
Trans Tech Publications Ltd
2007
Abstract
In the present work, the sintering behavior of high strength Al-5.6Zn-2.5Mg-1.6Cu (in wt.%) alloy compacts was investigated. Green parts made by pressing of mixed elemental powders were sintered at different temperatures between 400 and 600°C The effect of the sintering temperature on density, dimensional change and microstructure of the Al alloy was studied. Microstructural evaluation was accompanied by XRD and DSC methods in order to determine the temperature and chemical composition of the liquid phases formed during sintering. It was found that three transient liquid phases are formed at 420, 439 and 450°C Microstructural study revealed the progressive formation of sintered contacts due...
Washcoating and testing of monolithic palladium-only catalytic converters for automobiles
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Soltanieh, M ; Rashidzadeh, M ; Sharif University of Technology
2006
Abstract
This article presents the research results on production and performance of palladium-only catalytic converters. Monolith is used as catalyst carrier and gamma alumina as substrate. Dipping method is used for monolith washcoating. Palladium as the active metal is impregnated on gamma alumina using wet impregnation to produce catalyst samples. The effects of factors such as percent solid in slurry, milling time, calcination time and temperature, pH and existence of Al(NO3)3 on wash-coat characteristics were studied experimentally. SEM, XRD, and BET tests were carried out on the samples. Catalyst performance was tested in an experimental reactor that was designed for this research. The results...
Investigation of morphology and bioactive properties of composite coating of HA/vinyl acetate on pure titanium
, Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 128, Issue 1-3 , 2006 , Pages 243-249 ; 09215107 (ISSN) ; Yousefpour, M ; Xiudong, Y ; Li, X ; Yang, B ; Wu, Y ; Chen, J ; Xingdong, Z ; Sharif University of Technology
2006
Abstract
Electrochemical co-deposition approach was expanded to prepare composite bio-ceramic coating of hydroxyapatite (HA)/polyvinyl acetate on the surface of titanium. The role is to improve the bioactive and crystallization properties. The results of XRD, XPS, SEM and TEM characterization showed that by increasing amount of vinyl acetate in the composite bio-ceramic coating before and after immersing in the simulated body fluid (SBF), an oriented growth of HA planes on the (0 0 2) direction had been observed on titanium substrate. Also significant surface morphology changes were obtained
Thermally activated flux creep in the Gd(Ba2-xPrx)Cu3O7+δ system
, Article Superconductor Science and Technology ; Volume 16, Issue 4 , 2003 , Pages 538-544 ; 09532048 (ISSN) ; Akhavan, M ; Sharif University of Technology
2003
Abstract
The magnetoresistance of single-phase polycrystalline Gd(Ba2-xPrx)Cu3O7+δ samples has been studied within the thermally activated flux creep model. The decrease of pinning energy with applied magnetic field can be scaled to two power-law relations for magnetic fields, smaller and also larger than about 1 kOe. The derived Hc2(T), Hc2(O), and superconducting coherence length ξ show that the Pr doping, similar to weak links, decreases the vortex flux pinning energy. It is also concluded that the substitution of Pr at the Ba site has a more destructive effect on the flux dynamics than Pr at the rare-earth site
Production of Cu-TiC nanocomposite using mechanical alloying route
, Article Advanced Materials Research ; Vol. 829, issue , 2014 , pp. 572-576 ; ISSN: 10226680 ; Abachi, P ; Purazrang, K ; Rostami, A ; Sharif University of Technology
Abstract
In this study, Cu-TiC nanocomposites were produced by high energy ball milling of elemental powders and in-situ formation of TiC in the copper matrix. Cu-40wt% Ti powder mixture were milled for 60 h, then graphite powder was added, subsequently milling was continued for further 10 h. Based on theoretical calculations, at this composite, the amount of TiC as reinforcement should be 60.25vol% (45.47wt%). The effect of milling time on solution progress of titanium in the copper lattice was studied by X-Ray diffraction analysis (XRD) with CuKα radiation. Considering XRD of Cu-40wt%TiC after 60 h milling data and Williamson-Hall relation, crystallite size and lattice strain of copper were...
Synthesis and characterisation of β-tricalcium phosphate coating on zirconia toughened alumina by biomimetic method
, Article Advances in Applied Ceramics ; Volume 112, Issue 3 , 2013 , Pages 140-145 ; 17436753 (ISSN) ; Nemati, A ; Salahi, E ; Sharif University of Technology
2013
Abstract
The present work studied bioactive coatings on the surface of ceramic biomaterials. Zirconia toughened alumina (ZTA) composites containing 15 mol.-%. Partially stabilised zirconia was prepared after 1 h sintering at 1550°C. Apatite layers were then coated onto the surfaces of composites by the biomimetic method using 1·5-2 multiply concentrations of simulated body fluid (SBF). Before treatment in SBFs, a sodium silicate layer was employed as nucleating agent to induce the formation of a calcium phosphate layer. The effect of immersion time on the morphology of the precipitate was monitored with a scanning electron microscope. X dot maps revealed that there is a relationship between...