Search for: alloy
Total 1194 records
Biomass-derived wearable energy storage systems based on poplar tree-cotton fibers coupled with binary nickel-cobalt nanostructures, Article Sustainable Energy and Fuels ; Volume 4, Issue 2 , 2020 , Pages 643-654 ; Unalan, H. E ; Shahrokhian, S ; Sharif University of Technology
Royal Society of Chemistry 2020
We hereby demonstrate symmetric and asymmetric supercapacitors (SSCs and ASCs) based on core/shell-like Ni-Co oxide@cotton//Fe2O3-carbon nanotubes@cotton that are capable of storing a remarkable amount of energy, while retaining a high power density and long cycle life. Hierarchical, porous structures of Ni-Co-O nano-rod (NR) decorated Pd-activated cotton fibers (CFs) were fabricated using an eco-benign hydrothermal method and directly used as the cathode of the supercapacitors. Fe2O3-single-wall carbon nanotube (SWCNT) decorated CFs were employed as anodes of the fabricated ASCs. The assembled Ni-Co-O@cotton//Fe2O3-SWCNTs@cotton based ASCs possessed the benefits of a relatively high energy...
Influence of Y3+, Yb3+, Gd3+ cations on structural and electromagnetic properties of CuFe2O4 nanoferrites prepared via one step sol-gel method, Article Journal of Rare Earths ; Volume 39, Issue 10 , 2021 , Pages 1224-1231 ; 10020721 (ISSN) ; Akhtar, M. N ; Yousaf, M ; Batoo, K. M ; Aldossary, O. M ; Khan, S. N ; Sharif University of Technology
Editorial Office of Chinese Rare Earths 2021
Rare earths (REs) play a key role in distorting spinel structure by creating some defects at the lattice sites and make them suitable for magnetodielectric applications. In the present study, the nanoferrites of CuRE0.02Fe1.98O4, where REs = Y3+, Yb3+, Gd3+, were prepared using one step sol–gel method. The prepared samples are copper ferrite (CFO), yttrium doped copper ferrite (Y-CFO), ytterbium doped copper ferrite (Yb-CFO) and gadolinium doped copper ferrite (Gd-CFO), respectively. The single-phase structure of all the REs doped nanoferrites was determined by X-ray diffraction (XRD) analysis. The porosity, agglomerations and grain size of the REs doped copper ferrite were examined using...
Article Powder Technology ; Volume 208, Issue 3 , 2011 , Pages 623-627 ; 00325910 (ISSN) ; Yourdkhani, A ; Koohestani, H ; Sadrnezhaad, S. K ; Asmatulu, R ; Sharif University of Technology
Self-propagating exothermic reactions during mechanical milling of FeCl 3/CoCl 2 mixture together with sodium seeds resulted in formation of Fe 50Co 50 nanoparticles. Highly exothermic reactions resulted in temperature raise and formation of Fe 50Co 50 phase within the first 5min; however Fe 50Co 50 single-phase was obtained after 30min of milling. The products were characterized by XRD, SEM, EDS, TEM and VSM. Obtained results showed that both milling time and NaCl salt matrix affected the size, morphology, microstructure and magnetic properties of the produced particles
Synthesis and characterization of Al-SiC nanocomposites produced by mechanical milling and sintering, Article Advanced Composite Materials ; Volume 20, Issue 1 , 2011 , Pages 13-27 ; 09243046 (ISSN) ; Razavi Hesabi, Z ; Riedel, R ; Seyed Reihani, S. M ; Sharif University of Technology
Aluminum powder and various volume fractions of SiC particles with an average diameter of 50 nm were milled by a high-energy planetary ball mill to produce nanocrystalline Al-SiC nanocomposite powders. Double pressing/sintering process was used to consolidate powders to cylindrical specimens. It was shown that a double cycle of cold pressing and sintering can be utilized to obtain high density Al-SiC nanocomposite parts without using a hot-working step. High resolution scanning electron microscopy (HRSEM), X-ray diffraction (XRD) and laser particle size analyzer (PSA) were used to study the morphological and microstructural evolution of nanocomposite powders and bulk samples. The role of...
Low temperature nanostructured lithium titanates: Controlling the phase composition, crystal structure and surface area, Article Journal of Sol-Gel Science and Technology ; Volume 55, Issue 1 , 2010 , Pages 19-35 ; 09280707 (ISSN) ; Fray, D. J ; Sharif University of Technology
Low temperature lithium titanate compounds (i.e., Li4Ti 5O12 and Li2TiO3) with nanocrystalline and mesoporous structure were prepared by a straightforward aqueous particulate sol-gel route. The effect of Li:Ti molar ratio was studied on crystallisation behaviour of lithium titanates. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders were crystallised at the low temperature of 500 °C and the short annealing time of 1 h. Moreover, it was found that Li:Ti molar ratio and annealing temperature influence the preferable orientation growth of the lithium titanate compounds. Transmission electron microscope (TEM) images showed that the average...
In situ growth of vanadia-titania nano/micro-porous layers with enhanced photocatalytic performance by micro-arc oxidation, Article Electrochimica Acta ; Volume 55, Issue 9 , 2010 , Pages 3093-3102 ; 00134686 (ISSN) ; Moshfegh, A. Z ; Golestani Fard, F ; Sharif University of Technology
Micro-arc oxidation process was used to synthesize V2O5-TiO2 porous layers for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were also employed to evaluate phase structure and chemical composition of the layers. It was found that the V2O5-TiO2 layers consisted of anatase, rutile, and vanadium pentoxide phases fraction of which varied with the applied voltage and the electrolyte concentration. It was also revealed that pore size and surface roughness increased with the applied voltage and the electrolyte...
Article Applied Surface Science ; Volume 256, Issue 9 , 2010 , Pages 2903-2909 ; 01694332 (ISSN) ; Moshfegh, A. Z ; Golestani Fard, F ; Sharif University of Technology
V2O5-TiO2 layers with a sheet-like morphology were synthesized by micro arc oxidation process for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). Phase structure and chemical composition of the layers were also studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. It was revealed that the composite layers had a sheet-like structure average thickness of which was about 100 nm depending on the applied voltage. The layers consisted of anatase, rutile, and vanadium pentoxide phases fractions of which varied with the applied voltage. The optical properties...
Article IEEE Journal of Quantum Electronics ; Volume 46, Issue 2 , 2010 , Pages 228-237 ; 00189197 (ISSN) ; Sodagar, M ; Eftekharian, A ; Khorasani, S ; Sharif University of Technology
In this paper, we present an envelope function analysis technique for the design of the emission spectra of a white quantum-well light-emitting diode (QWLED). The nano- metric heterostructure that we are dealing with is a multiple QW, consisting of periods of three single QWs with various well thicknesses. With the aid of 6 × 6 Luttinger Hamiltonian, we employ the combination of two methods, k · p perturbation and the transfer matrix method, to acquire the electron and hole wave functions numerically. The envelope function approximation was considered to obtain these wave functions for a special basis set. While adjacent valence sub-bands have been determined approximately, the conduction...
Vertically standing Cu2O nanosheets promoted flower-like PtPd nanostructures supported on reduced graphene oxide for methanol electro-oxidation, Article Electrochimica Acta ; Volume 259 , 2018 , Pages 36-47 ; 00134686 (ISSN) ; Rezaee, S ; Sharif University of Technology
Elsevier Ltd 2018
The present study reports a simple electrochemical approach to the fabrication of a new nanocomposite containing PtPd nanoflowers (NFs) promoted with two-dimensional (2D) nanosheets (NSs) structure cuprous oxide (Cu2O) supported on reduced graphene oxide (rGO) (PtPd-NFs/Cu2O-NSs/rGO). Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectra, Raman spectroscopy, and energy dispersive X-ray spectroscopy are used for characterization of the PtPd-NPs/Cu2O-NPs/rGO. SEM images showed that vertical-standing arrays of Cu2O with an edge length up to 1 μm and thickness of about 20 nm are electrodeposited on the surface of rGO film. Also, PtPd needle-like NFs with visible and...
Nickel-cobalt layered double hydroxide ultrathin nanosheets coated on reduced graphene oxide nonosheets/nickel foam for high performance asymmetric supercapacitors, Article International Journal of Hydrogen Energy ; Volume 43, Issue 4 , 2018 , Pages 2256-2267 ; 03603199 (ISSN) ; Rahimi, S ; Mohammadi, R ; Sharif University of Technology
Elsevier Ltd 2018
Here in, for the first time, we report a new and simple procedure for preparing reduced graphene oxide/nickel-cobalt double layered hydroxide composite on the nickel foam (Ni-Co LDH/rGO/NF) via a fast and simple two-step electrochemical method including potentiostatic routes in the presence of CTAB as a cationic surfactant. Graphene oxide coated nickel foam prepared by simple immersion method. After that, the prepared electrode reduced electrochemically to obtain rGO/NF electrode. Finally, the rGO/NF electrode was used as cathode for electrodeposition of Ni-Co LDH in the presence of CTAB as cationic surfactant. The prepared electrodes were characterized by field emission scanning electron...
Study the sintering behavior of nanocrystalline 3Y-TZP/430L stainless-steel composite layers for co-powder injection molding, Article Journal of Materials Science ; Volume 44, Issue 5 , 2009 , Pages 1264-1274 ; 00222461 (ISSN) ; Simchi, A ; Sharif University of Technology
Recently, co-powder injection molding process (2C-PIM) has attained considerable interest to fabricate complex-shaped functional materials. The aim of this work is to study the sintering compatibility between nanocrystalline yttria-stabilized zirconia (3Y-TZP) and PIM grade 430L stainless steel (SS) powders, which is the utmost important step in the 2C-PIM process. To evaluate the mismatch strain development during the co-sintering, the isothermal and nonisothermal behaviors of the ceramic and metal powders were studied. Small bilayers of 3Y-TZP/430L were made by a powder metallurgy technique and the feasibility of simultaneous sintering and joining of the composite layer was examined....
Low-temperature perovskite-type cadmium titanate thin films derived from a simple particulate sol-gel process, Article Acta Materialia ; Volume 57, Issue 4 , 2009 , Pages 1049-1059 ; 13596454 (ISSN) ; Fray, D. J ; Sharif University of Technology
Low-temperature perovskite-type cadmium titanate (CdTiO3) with a nanocrystalline and mesoporous structure was prepared at various Ti:Cd molar ratios by a straightforward particulate sol-gel route. The prepared sols had a narrow particle size distribution, in the range 23-26 nm. X-ray diffraction and Fourier transform infrared spectroscopy revealed that the powders contained a mixture of ilmenite-CdTiO3, perovskite-CdTiO3, anatase and rutile phases, depending on the annealing temperature and the Ti:Cd molar ratio. Perovskite-CdTiO3 was the major type obtained from cadmium-prominent powders at low temperature, whereas ilmenite-CdTiO3 was the major type obtained from titanium-prominent powders...
Adsorption of eco-friendly carthamus tinctorius on steel surface in saline solution: a combination of electrochemical and theoretical studies, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 601 , 20 September , 2020 ; Ramazani Saadat Abadi,A ; Mahdavian, M ; Bahlakeh, G ; Haddadi, S. A
Elsevier B.V 2020
In this study, the different parts of carthamus tinctorius plant, including petal (SPE), leaf (SLE), and shoot (SSE), have been extracted. Adsorption of the extracts on mild steel in 3.5 wt. % NaCl solution was evaluated employing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and electrochemical noise measurements (EN). The field-emission scanning electron microscopy (FE-SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were employed to appraise the morphology of the samples surface subjected to the test solutions. According to the EIS results, the maximum adsorption efficiency belonged to the solution containing 1 g L−1 of...
Synthesis and characterisation of nanosized TiO2-ZrO2 binary system prepared by an aqueous sol-gel process: Physical and sensing properties, Article Sensors and Actuators, B: Chemical ; Volume 155, Issue 2 , July , 2011 , Pages 568-576 ; 09254005 (ISSN) ; Fray, D. J ; Sharif University of Technology
Nanostructured TiO2-ZrO2 thin films and powders were prepared by a straightforward aqueous particulate sol-gel route. Titanium (IV) isopropoxide and zirconium (IV) acetate hydrate were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the specific surface area. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy revealed that the powder were crystallised at the low temperature of 500 °C, containing anatase-TiO 2 and tetragonal-ZrO2 phases. Furthermore, it was found that ZrO2 retarded the anatase-to-rutile transformation up to 900 °C. The activation energies for crystallite growth of TiO2 and ZrO2 components in...