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Molybdenite alkali fusion and leaching:reactions and mechanism

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 127-131页

作者： reza ebrahimi-kahrizsangi Mohammad Hasan Abbasi Ali Saidi Department of Materials Engineering Islamic Azad University Department of Materials Engineering Isfahan University of Technology

The production of MoO3 from Sarcheshmeh molybdenite concentrate via a pyro-hydrometallurgical process was *** molybdenite concentrate and sodium carbonate were premixed and fused under air *** the fused products were leached in water and the dissolved molybdenum was recovered as ammonium *** ammonium molybdate was then calcined to produce mo-lybdic *** the fusion stage,the effect of the mass ratio of carbonate to sulfide on the reaction products and the solubility of the products was *** results show that during the fusion,sodium molybdate and sodium sulfate are the final reaction products and sodium sulfide is detected as an intermediate reaction *** melting at 850℃with 5wt%excess carbonate,the maximum solubility of the products is *** molybdenum is recovered from the solutions as ammonium molybdate.

关键词： molybdenite alkali fusion leaching sodium molybdate molybdic oxide

Effect of milling atmosphere on structural and magnetic properties of Ni-Zn ferrite nanocrystalline

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Chinese Physics B 2015年第4期24卷 481-490页

作者： Abdollah Hajalilou Mansor Hashim reza ebrahimi-kahrizsangi Mohamad Taghi Masoudi Material Synthesis and Characterization Laboratory Institute of Advanced Technology (ITMA)Universiti Putra Malaysia Advanced Materials Research Center Materials Engineering Department Najafabad Branch Islamic Azad University

Powder mixtures of Zn, NiO, and Fe2O3 are mechanically alloyed by high energy ball milling to produce Ni-Zn ferrite with a nominal composition of Ni0.36Zn0.64Fe2O4. The effects of milling atmospheres （argon, air, and oxygen）, milling time （from 0 to 30 h） and heat treatment are studied. The products are characterized using x-ray diffractometry, field emission scanning electron microscopy equipped with energy-dispersive x-ray spectroscopy, and transmitted electron microscopy. The results indicate that the desired ferrite is not produced during the milling in the samples milled under either air or oxygen atmospheres. In those samples milled under argon, however, Zn/NiO/Fe2O3 reacts with a solid-state diffusion mode to produce Ni-Zn ferrite nanocrystalline in a size of 8 nm after 30-h-milling. The average crystallite sizes decrease to 9 nm and 10 nm in 30-h-milling samples under air and oxygen atmospheres, respectively. Annealing the 30-h-milling samples at 600℃ for 2 h leads to the formation of a single phase of Ni-Zn ferrite, an increase of crystallite size, and a reduction of internal lattice strain. Finally, the effects of the milling atmosphere and heating temperature on the magnetic properties of the 30-h-milling samples are investigated.

关键词： Ni-Zn ferrite nanocrystalline mechanical alloying milling atmosphere milling time magnetic property

Influence of growth conditions on the electrochemical synthesis of SnS thin films and their optical properties

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International Journal of Minerals,Metallurgy and Materials 2016年第3期23卷 348-357页

作者： Hosein Kafashan Farid Jamali-Sheini reza ebrahimi-kahrizsangi Ramin Yousefi Advanced Materials Research Center Materials Engineering DepartmentNajafabad BranchIslamic Azad UniversityNajafabadIsfahanIran Department of Physics Ahvaz BranchIslamic Azad UniversityAhvazIran Department of Physics Masjed-Soleiman BranchIslamic Azad University(I.A.U)Masjed-SoleimanIran

Tin sulfide （SnS） thin films were prepared by electrodeposition onto fluorine-doped tin oxide （FTO） glass substrates using an aqueous solution containing SnCl2 and Na2S2O3 at various deposition potentials （L） and bath concentrations. The pH value and temperature of the solution were kept constant. The deposited films were characterized using X-ray diffraction （XRD）, field-emission scanning electron microscopy （FESEM）, photoluminescence （PL）, and ultraviolet-visible （UV-Vis） spectroscopy. The FESEM images demonstrated that changes in the deposition potential （E） and solution concentration led to marked changes in the morphology of the deposited SnS films. Energy-dispersive X-ray analysis （EDXA） results showed that the SrdS atomic ratio strongly depended on both the solution concentration and the deposition potential. To obtain an SrdS atomic ratio approximately equal to l, the optimal Sn2＋/S2O2- 3 molar ratio and E parameter were 1/8 and -1.0 V, respectively. The XRD patterns showed that the synthesized SnS was obviously polycrystalline, with an orthorhombic structure. The effects of the variations of bath concentration and deposition potential on the band-gap energy （Eg） were studied using PL and UV-Vis experiments. The PL spectra of all the SnS films contained two peaks in the visible region and one peak in the infrared （IR） region. The UV-Vis spectra showed that the optical band-gap energy varies from 1.21 to 1.44 eV.

关键词： tin sulfide thin films electrodeposition structural properties optical properties

Facile Growth of Porous Hierarchical Structure of ZnO Nanosheets on Alumina Particles via Heterogeneous Precipitation

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Journal of Materials Science & Technology 2013年第10期29卷 915-918页

作者： Hamid Tajizadegan Majid Jafari Mehdi Rashidzadeh reza ebrahimi-kahrizsangi Omid Torabi Department of Materials Engineering Najafabad BranchIslamic Azad University Catalysis & Nanotechnology Research Division Research Institute of Petroleum Industry (RIPI)

ZnO nanosheets and nanoflakes were grown on alumina particles in the absence of surfactants via heterogeneous precipitation using urea, zinc acetate and bayerite as precursors. Thermo-gravimetric analysis （TGA）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FTIR） were used and the results indicated the formation of only two phases： wurtzite-type ZnO and γ-Al2O3. ZnO nanoflakes were grown on alumina particles in the samples with ZnO content of 40 and 60 wt%, By increasing the ZnO content to 80 wt%, a porous hierarchical structure of ZnO with nanosheet arrays appeared. Both of these nanoflakes and nanosheets were about 40-80 nm in thickness and about 1-2 μm in diameter. It was proposed that Zns（CO3）2（OH）6 nuclei undergo higher growth rates in thin sheets at edges of bayerite particles with a higher surface energy. The Brunauer-Emmett-Teller （BET） measurements proved a reachable high surface area for hierarchical structures of ZnO nanosheets, which could mainly be attributed to their unique growth on alumina particles. Also, UV absorption results revealed that ZnO--Al2O3 compositions still show the UV characteristic absorption of ZnO, which can evidence the presence of photocatalytic properties in ZnO-Al2O3 compositions.

关键词： ZnO Crystal growth Heterogeneous nucleation Hierarchical structures High surface area Morphology evolution

Novel ZnO-Al_2O_3 composite particles as sorbent for low temperature H_2S removal

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Chinese Chemical Letters 2013年第2期24卷 167-169页

作者： Hamid Tajizadegan Mehdi Rashidzadeh Majid Jafari reza ebrahimi-kahrizsangi Department of Materials Engineering Najafabad BranchIslamic Azad University Catalysis & Nanotechnology Research Division Research Institute of Petroleum Industry(RIPI) Department of Materials Engineering.Najafabad Branch.Islamic Azad University

Received 28 September 2012 Received in revised form 13 December 2012 Accepted 24 December 2012 Available online 4 February 2013

关键词： ZnOH2SCompositeSurface area

Electroplating of Ni/Co–pumice multilayer nanocomposite coatings: Effect of current density on crystal texture transformations and corrosion behavior

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International Journal of Minerals,Metallurgy and Materials 2019年第10期26卷 1299-1310页

作者： Mehdi Boroujerdnia Hamid Ghayour Ahmad Monshi reza ebrahimi-kahrizsangi Farid Jamali-Sheini Advanced Materials Research Center Department of Materials EngineeringNajafabad BranchIslamic Azad UniversityNajafabadIran Advanced Surface Engineering and Nano Materials Research Center Department of PhysicsAhvaz BranchIslamic Azad UniversityAhvazIran

The present paper aims to investigate the influence of the current density in the electroplating process on the microstructure, crystal texture transformations, and corrosion behavior of Ni/Co pumice multilayer nanocomposite coatings. The Ni/Co pumice composite coatings were prepared by deposition of Ni, followed by the simultaneous deposition of pumice nanoparticles (NPs) in a Co matrix via an electroplating process at various current densities. Afterward, the morphology, size, topography, and crystal texture of the obtained samples were investigated. Furthermore, electrochemical methods were used to investigate the corrosion behavior of the produced coatings in a solution of 3.5wt% NaCl. The results indicated that increasing the plating current density changed the mechanism of coating growth from the cell state to the column state, in- creased the coating thickness, roughness, and texture coefficient (TC) of the Co (203) plane, and reduced the amount of pumice NPs incorporated into the Ni/Co pumice composite. The electrochemical results also indicated that increasing the current density enhanced the corrosion resistance of the Ni/Co pumice composite.

关键词： electroplating current density Ni/Co pumice corrosion resistance crystal texture of coating

Role of interlayer composition in microstructure and mechanical properties during TLP bonding of GTD-111/IN-718 superalloys

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Transactions of Nonferrous Metals Society of China 2022年第3期32卷 908-926页

作者： Ali IZADI GHAHFEROKHI Masoud KASIRI-ASGARANI Kamran AMINI Mahdi RAFIEI reza ebrahimi-kahrizsangi Advanced Materials Research Center Department of Materials EngineeringNajafabad BranchIslamic Azad UniversityNajafabadIran Center for Advanced Engineering Research Majlesi BranchIslamic Azad UniversityIsfahanIran

An investigation was carried out to assess the applicability of transient liquid phase bonding of two dissimilar super-alloys with different interlayers. The effect of using three types of interlayer such as BNi-2, BNi-3, and BNi-9 on microstructure and mechanical properties was studied in the GTD-111/IN-718 system at 1100 ℃ for different bonding time. To determine the compositional changes and microstructure in the joint region, field emission scanning electron microscopy equipped with energy dispersive spectroscopy was utilized. The formation of Ni_(3)B in the athermally solidified zone(ASZ) is controlled by the B content and, accordingly, the morphology of Ni_(3)Si is governed by the Si content. The Cr content might impede the relocation of B from the interlayer into the base metal and the formation of CrB inside the ASZ is dominated by the Cr content. The high micro-hardness of the eutectic compounds is originated from the formation of boride matrixes such as Ni or Cr boride. The shear strength of the joint using BNi-9 after the completion of isothermal solidification is lower compared that that using BNi-3 and BNi-2, which could be related to the absence of Si in the filler metals constituent and the significant presence of Cr in BNi-9.

关键词： transient liquid phase bonding Ni-based superalloy isothermal solidification Ni-B compounds

Nonlinear phenomena in vibrations of embedded carbon nanotubes conveying viscous fluid

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Nanotechnology and Precision Engineering 2024年第1期7卷 44-54页

作者： reza ebrahimi Mechanical Engineering Faculty of EngineeringYasouj UniversityYasouj 75918-74831Iran

Various nonlinear phenomena such as bifurcations and chaos in the responses of carbon nanotubes(CNTs)are recognized as being major contributors to the inaccuracy and instability of nanoscale mechanical ***,the main purpose of this paper is to predict the nonlinear dynamic behavior of a CNT conveying viscousﬂuid and supported on a nonlinear elastic *** proposed model is based on nonlocal Euler–Bernoulli beam *** Galerkin method and perturbation analysis are used to discretize the partial differential equation of motion and obtain the frequency-response equation,respectively.A detailed parametric study is reported into how the nonlocal parameter,foundation coefﬁcients,ﬂuid viscosity,and amplitude and frequency of the external force inﬂuence the nonlinear dynamics of the ***,quasi-periodic,and chaotic behaviors and hardening nonlinearity are revealed by means of the vibration time histories,frequency-response curves,bifurcation diagrams,phase portraits,power spectra,and Poincaré***,the results show that it is possible to eliminate irregular motion in the whole range of external force amplitude by selecting appropriate parameters.

关键词： Nonlinear vibration Carbon nanotubes Nonlocal effect Viscousﬂuid Nonlinear elastic medium

Assessment of physical properties of nano-crystal hydroxyapatite scaffold coated with poly-hydroxybutyrate for bone tissue engineering

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Assessment of physical properties of nano-crystal hydroxyapa...