@article { author = {Barzegar Vishlaghi, Mahsa and Ataei, Abolghasem}, title = {Characterization of the metastable Cu-Fe nanoparticles prepared by the mechanical alloying route}, journal = {Journal of Ultrafine Grained and Nanostructured Materials}, volume = {47}, number = {2}, pages = {57-61}, year = {2014}, publisher = {University of Tehran}, issn = {2423-6845}, eissn = {2423-6837}, doi = {10.7508/jufgnsm.2014.02.001}, abstract = {Although Cu and Fe are immiscible under equilibrium conditions, they can form supersaturated solid solutions by mechanical alloying. In this paper, nano-structured of the metastable Cu-Fe phase containing 10, 15, 20 and 25% wt Fe were synthesized by intensive ball milling for 15h, in order to achieve a solid solution of Fe in Cu. The phase composition, dissolution of the Fe atoms into the Cu matrix, and the morphology of the milling products were studied by X-ray Diffraction (XRD), Energy Dispersive Spectrometer (EDS), and Field Emission Scanning Electron Microscope (FESEM) techniques, respectively. The mean crystallite size of the milled samples was determined by XRD peak broadening using the Williamson-Hall approximation. The XRD analysis results showed that the solid solubility of the Fe in the Cu was extended to 20%wt after milling for 15 h, and a homogeneous solid solution of Cu80Fe20 with a mean crystallite size of 19nm was obtained. The mean crystallite size decreased with increasing milling time and it was more evident in the initial stage of the milling. The Cu lattice parameter increased by dissolving the Fe into the Cu matrix probably due to the magneto-volume effect in the Cu-Fe alloys. The FESEM observations showed that the milling products were agglomerates consisting of uniform particles. The Vibrating Sample Magnetometer (VSM) results showed that the Cu80Fe20 powder has soft magnetic properties.}, keywords = {Cu-Fe,Mechanical alloying,Metastable,Nano-structure}, url = {https://jufgnsm.ut.ac.ir/article_52795.html}, eprint = {https://jufgnsm.ut.ac.ir/article_52795_a8c44da80df036f374a25a80eda78894.pdf} } @article { author = {Bernoosi, Samaneh and Azari Khosroshahi, Rasoul and Taherzadeh Mousavian, Reza}, title = {Mechanical properties of hot-pressed Al-4.5 wt. % Cu/WC composite}, journal = {Journal of Ultrafine Grained and Nanostructured Materials}, volume = {47}, number = {2}, pages = {63-70}, year = {2014}, publisher = {University of Tehran}, issn = {2423-6845}, eissn = {2423-6837}, doi = {10.7508/jufgnsm.2014.02.002}, abstract = {In this study, the elemental powders of aluminum and copper were initially subjected to mechanical alloying using an attrition ball mill under argon atmosphere to produce an Al-4.5 wt% Cu powder alloy. The WC nanoparticles were then added to the powder alloy and milled in a planetary ball mill to explore the role of the WC nanoparticles on the mechanical properties of the fabricated composite powder. The experimental results revealed that a solid solution of Al-Cu could be formed after MA and a good dispersion of the WC nanoparticles in the aluminum matrix was obtained as characterized using X-ray diffraction and scanning electron microscopy, respectively. The results of hardness and compression tests of the hot pressed composites indicated that the MA followed by the hot-press processes was successful to fabricate an alloy and a metal matrix composite with considerable mechanical properties. However, a decreasing trend in the hardness and strength of the composites with the WC contents of more than 5wt% was observed. The maximum values of 260 HV and 575 MPa were obtained for a composite containing 5 wt% of nano ceramic particles.}, keywords = {Al-4.5 wt% Cu,Metal matrix composite,Mechanical alloying,Microstructural characterization,WC nanoparticle}, url = {https://jufgnsm.ut.ac.ir/article_52796.html}, eprint = {https://jufgnsm.ut.ac.ir/article_52796_449e67a4db698a03bb8d18eae6b731a6.pdf} } @article { author = {Fathi, Mohammad and Saghafi, Morteza and Mahboubi, Farzad}, title = {Graphene oxide nanoribbons and their applications in supercapacitors}, journal = {Journal of Ultrafine Grained and Nanostructured Materials}, volume = {47}, number = {2}, pages = {71-76}, year = {2014}, publisher = {University of Tehran}, issn = {2423-6845}, eissn = {2423-6837}, doi = {10.7508/jufgnsm.2014.02.003}, abstract = {We report the enhanced capacitance of the Multi-Walled Carbon NanoTubes (MWCNTs) after a chemical unzipping process in concentrated sulfuric acid (H2SO4) and potassium permanganate (KMnO4). The effects of the test duration and temperature were investigated on the unzipping process of the MWCNTs to synthesize the graphene oxide nanoribbons. The SEM and TEM studies were carried out on untreated and unzipped MWCNTs samples to investigate the cutting and unzipping of the MWCNTs. The results confirmed that the efficient tube unzipping with improved effective surface area was obtained from the 1h treatment at 60°C, at which most of the tubes were opened without any tube annihilation. The graphite plate deposited with the untreated and unzipped MWCNTs samples was investigated by electrochemical studies. Cyclic voltammetry studies showed that the MWCNTs after 1h unzipping at 60°C had better electrochemical behavior than the other samples. Galvanostatic charging/discharging measurements were carried out on the untreated and unzipped MWCNTs samples. A remarkable specific capacitance of 33 Fg-1 was obtained for the unzipped MWCNTs at a current density of 1 Ag-1 in 0.5 M KCl solution compared with 8 Fg-1 for pristine MWCNTs, again confirming the enhanced effective surface area and increased defect density in the tube surfaces after the unzipping process. These results make the unzipped MWCNTs a promising electrode material for all energy storage applications.}, keywords = {supercapacitor,Unzipped MWCNTs,Specific capacitance,Enhanced effective surface area}, url = {https://jufgnsm.ut.ac.ir/article_52797.html}, eprint = {https://jufgnsm.ut.ac.ir/article_52797_186e07d19d6f1b1844c2fca04cddc4a7.pdf} } @article { author = {Abdollahi, Alireza and Alizadeh, Ali}, title = {A Tri-modal 2024 Al -B4C composites with super-high strength and ductility: Effect of coarse-grained aluminum fraction on mechanical behavior}, journal = {Journal of Ultrafine Grained and Nanostructured Materials}, volume = {47}, number = {2}, pages = {77-88}, year = {2014}, publisher = {University of Tehran}, issn = {2423-6845}, eissn = {2423-6837}, doi = {10.7508/jufgnsm.2014.02.004}, abstract = {In this study, ultrafine grained 2024 Al alloy based B4C particles reinforced composite was produced by mechanical milling and hot extrusion. Mechanical milling was used to synthesize the nanostructured Al2024 in attrition mill under argon atmosphere up to 50h. A similar process was used to produce Al2024-5%wt. B4C composite powder. To produce trimodal composites, milled powders were combined with coarse grained aluminum in 30 and 50 wt% and then were exposed to hot extrusion at 570°C. The microstructure of hot extruded samples were studied by optical microscope, Transmission electron microscope (TEM) and scanning electron microscope (SEM) equipped with EDS spectroscopy. The mechanical properties of samples were compared by using tensile, compression and hardness tests. The results showed that the strength, after 50 h milling and addition of 5wt% B4C, increased from 340 to 582 MPa and the hardness increased from 87 HBN to 173 HBN, but the elongation decreased from 14 to 0.5%. By adding the coarse-grained aluminum powder, the strength and hardness decreased slightly, but the increases in return. Ductility increase is the result of increase in dislocation movements and strength increase is the result of restriction in plastic deformation by nanostructured regions. Furthermore, the strength and hardness of trimodal composites were higher, but their ductility was lower.}, keywords = {aluminum matrix composites,ultra-fine grained materials,trimodal composites,carbides}, url = {https://jufgnsm.ut.ac.ir/article_52798.html}, eprint = {https://jufgnsm.ut.ac.ir/article_52798_f5344faff8a5ee371b68a2a79d88b882.pdf} } @article { author = {Keyvani, Ahmad and Saremi, Mohsen and Heydarzadeh Sohi, Mahmoud}, title = {Oxidation resistance of the nanostructured YSZ coating on the IN-738 superalloy}, journal = {Journal of Ultrafine Grained and Nanostructured Materials}, volume = {47}, number = {2}, pages = {89-96}, year = {2014}, publisher = {University of Tehran}, issn = {2423-6845}, eissn = {2423-6837}, doi = {10.7508/jufgnsm.2014.02.005}, abstract = {Conventional and nanostructured YSZ coatings were deposited on the IN-738 Ni super alloy by the atmospheric plasma spray technique. The oxidation was measured at 1100°C in an atmospheric electrical furnace. According to the experimental results the nanostructured coatings showed a better oxidation resistance than the conventional ones. The improved oxidation resistance of the nanocoating could be explained by the change in structure to a dense and more packed structure in this coating. The mechanical properties of the coatings were tested using the thermal cyclic, nanoindentation and bond strength tests, during which the nanostructured YSZ coating showed a better performance by structural stability.}, keywords = {Plasma spray,Nanostructure,oxidation,Nanoindentation}, url = {https://jufgnsm.ut.ac.ir/article_52799.html}, eprint = {https://jufgnsm.ut.ac.ir/article_52799_ccfb40fd5bf217dcef3b051e0dc40485.pdf} } @article { author = {Ghazanfari, Mahdi and Johar, Fatemeh and Yazdani, Ahmad}, title = {Synthesis and characterization of Fe3O4@Ag core-shell: structural, morphological, and magnetic properties}, journal = {Journal of Ultrafine Grained and Nanostructured Materials}, volume = {47}, number = {2}, pages = {97-103}, year = {2014}, publisher = {University of Tehran}, issn = {2423-6845}, eissn = {2423-6837}, doi = {10.7508/jufgnsm.2014.02.006}, abstract = {This paper is a report on the synthesis of the Fe3O4@Ag core-shell with high saturation magnetization of magnetite nanoparticles as the core, by using polyol route and silver shell by chemical reduction. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy analyses confirmed that the particles so produced were monophase. The magnetic properties of the product were investigated by using a vibrating sample magnetometer. Magnetic saturation of magnetite was 91 emu/g that around about bulk magnetization. This high saturation magnetization can be attributed to the thin dead layer. By using polyethylene glycol as a surfactant to separate and restrict the growth of the particles, magnetostatic interactions are in good agreement with the remanence ratio analysis. Morphology and the average size of the particles were determined with field emission scanning electron microscope (FESEM). Spherical aggregates of Fe3O4 (size around 73 nm) are composed of a small primary particle size of about 16 nm. Silver deposition was done using butylamine as the reductant of AgNO3 in ethanol with different ratio. The silver layers were estimated using statistical histogram images of FESEM. Silver-coated iron oxide nanohybrids have been used in a broad range of applications, including chemical and biological sensing, due to the broad absorption in the optical region associated with localized surface plasmon resonance.}, keywords = {Magnetite,silver,polyol,core-shell,magnetic saturation}, url = {https://jufgnsm.ut.ac.ir/article_52800.html}, eprint = {https://jufgnsm.ut.ac.ir/article_52800_f6fa85f609c15c891c921aea8193d4e1.pdf} } @article { author = {Jafari, Vajihe and Allahverdi, Ali}, title = {Synthesis of nanosilica from silica fume using an acid-base precipitation technique and PVA as a nonionic surfactant}, journal = {Journal of Ultrafine Grained and Nanostructured Materials}, volume = {47}, number = {2}, pages = {105-112}, year = {2014}, publisher = {University of Tehran}, issn = {2423-6845}, eissn = {2423-6837}, doi = {10.7508/jufgnsm.2014.02.007}, abstract = {The purpose of the present study was to synthesize and characterize nanosilica from alkali-extraction of silica fume under controlled conditions using poly (vinyl alcohol) (PVA) as a dispersing agent. The dissolution efficiency of silica fume was affected by various factors such as concentration of the reagent, reaction time and temperature. A maximum dissolution efficiency of 91% was achieved at the sodium hydroxide solution concentration of 2.5 M, after areaction time of 30 minutes and at areaction temperature of 80°C. The microstructure and morphology of the obtained nanosilica powder at the optimum conditions were characterized using scanning electron microscopy (SEM). SEM images confirmed the formation of smaller and less agglomerated nanosilica particles due to the existence of the surfactant. Further, the synthesized nanosilica was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRF) and X-ray diffraction (XRD). The results show that the synthesized nanosilica consisted of pure silica particles.}, keywords = {nanosilica,Silica Fume,dissolution efficiency,Surfactant,PVA}, url = {https://jufgnsm.ut.ac.ir/article_52801.html}, eprint = {https://jufgnsm.ut.ac.ir/article_52801_ee3cc003fdae2f3b5263593bc072bcb6.pdf} } @article { author = {Poortavasoly, Hajar and Montazer, Majid}, title = {Functional polyester fabric through simultaneous aminolysis and nano ZnO synthesis}, journal = {Journal of Ultrafine Grained and Nanostructured Materials}, volume = {47}, number = {2}, pages = {113-119}, year = {2014}, publisher = {University of Tehran}, issn = {2423-6845}, eissn = {2423-6837}, doi = {10.7508/jufgnsm.2014.02.008}, abstract = {Here, in situ synthesis of nano zinc oxide, along with aminolysis of polyester fabric, has simultaneously been carried out by using triethanol amine (TEA) and zinc acetate. The ZnO nano particles (NPs) were formed and stabilized on the fabric surface by amine compound at 130 °C for 1 h. The synthesis of nano ZnO particles on the polyester fabric were confirmed by X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images. The mean size of ZnO NP was obtained with SEM about 51.38 nm, however, XRD data indicated the crystalline ZnO NPs with a mean crystal size of 14.68 nm on the fabric surface. Further, self-cleaning performance of the treated fabrics was studied by degradation of methylene blue (MB) in aqueous solution under daylight irradiation. The stability of ZnO NPs on the fabric surface was studied by evaluating the self-cleaning and hydrophilicity properties of the samples after standard washing. Also, the hydrophilicity of the treated polyester fabric was improved due to aminolysis of the fabric and the required time for water droplet to spread on the treated fabric after one week exposure to daylight reduced. Overall, TEA was a suitable reducing agent to prepare homogenous ZnO NPs on the polyester fabric.}, keywords = {Aminolysis,Nano zinc oxide,Self-cleaning,Photo activity,Triethanol amine}, url = {https://jufgnsm.ut.ac.ir/article_52900.html}, eprint = {https://jufgnsm.ut.ac.ir/article_52900_95290572024f3a9d90978528dd1f4685.pdf} }