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Preparation of nanostructure silver powders by mechanical decomposing and mechanochemical reduction of silver oxide

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Transactions of Nonferrous Metals Society of China 2013年第5期23卷 1520-1524页

作者： gholam reza khayati Kamal JANGHORBAN Department of Material Science and Engineering Shahid Bahonar University of Kerman Materials Science and Engineering Department School of EngineeringShiraz University

The mechanical decomposing and mechanochemical reductions of silver oxide for preparation of nanocrystalline silver powders by high planetary ball mill was investigated. XRD and HRSEM techniques were used to characterize the structural evolution and morphological changes of products. The results show that the nanostructured silver with an average crystallite size of 14 nm and internal strain of 0.75% is synthesized by mechanical decomposing of Ag2O after 95 h milling. While, the product of mechanochemical reduction of silver oxide using graphite after 22 h milling is nanostructured silver with an average crystallite size of 28 nm and internal strain of 0.44%.

关键词： nanocrystalline silver silver oxide mechanical decomposing mechanochemical reduction

Kinetics analysis of non-isothermal decomposition of Ag_2O-graphite mixture

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Transactions of Nonferrous Metals Society of China 2014年第9期24卷 2991-3000页

作者： Seyed Hadi SHAHCHERAGHI gholam reza khayati Department of Mineral Processing Engineering Shahid Bahonar University of KermanKerman Iran Department of Materials Science and Engineering Shahid Bahonar University of KermanKerman Iran

The thermal decomposition kinetics of Ag2O-graphite mixture was systematically studied using a differential scanning calorimeter（DSC） in terms of model-fitting Malek approach, integral master plot method and model-free advanced isoconversional method of Vyazovkin. The results showed that the thermal decomposition occurred in two stages. The first step was the decomposition process of Ag2 O to form porous silver particles as a complex process with the participation of at least two mechanisms, and the second step corresponded to the structural change from porous particles to silver bulk crystals as a single-step process.

关键词： Ag2O advanced isoconversional method kinetic modeling Sestak–Berggren model

Arrhenius parameters determination in non-isothermal conditions for mechanically activated Ag_2O-graphite mixture

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Transactions of Nonferrous Metals Society of China 2014年第12期24卷 3994-4003页

作者： Seyed Hadi SHAHCHERAGHI gholam reza khayati Department of Mineral Processing Engineering Shahid Bahonar University of Kerman Department of Materials Science and Engineering Shahid Bahonar University of Kerman

The non-isothermal kinetics of mechanochemical reduction of Ag2O with graphite was studied by DSC and TGA with a model of fitting Malek approach and a model-free advanced isoconversional method of Vyazovkin. To evaluate the kinetics parameters, Ag2O–graphite mixture of as-received and milled for 2 and 4 h samples were selected. Based on the results obtained by Vyazovkin method calculation, however, the difference between the maximum and minimum values of activation energy is less than 20%-30%of the average activation energy （（99.38±2.36） kJ/mol） and thermal decomposition of mechanically activated Ag2O for 2 h is a multi-step process. Moreover, the thermal decomposition of mechanically activated Ag2O–graphite powder activated for 4 h is a single-step process （the average activation energy=（93.68±2.26） kJ/mol）. The kinetics modeling shows that the complexity of thermal decomposition of as-received Ag2O–graphite mixture is higher than that of the others. While, the autocatalytic tendency of as-received Ag2O–graphite mixture is lower than that of the others.

关键词： mechanical activation Vyazovkin method kinetic modeling Sestak-Berggren model integral master plot method silver oxide

Review of electrodeposition methods for the preparation of high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2022年第9期29卷 1683-1696页

作者： Zahra Shojaei gholam reza khayati Esmaeel Darezereshki Department of Materials Science and Engineering Shahid Bahonar University of KermanKerman 76135-133Iran

High-entropy alloys(HEAs)are suitable for engineering applications requiring excellent mechanical,corrosion,thermal,and magnetic *** the last decade,electrodeposition has emerged as a promising synthesis technique for *** has focused on the influence of procedure parameters on the deposition of different HEA layers and the effect of their microstructure on their corrosion and magnetic *** review of current literature provides comprehensive information on HEAs and the use of direct and pulse electrodeposition as a synthesis technique for these *** review also addresses the research gaps on HEA production via electrodeposition,such as using other ceramic particles instead of graphene oxide in composite structures based on HEAs.

关键词： high-entropy alloy electrodeposition corrosion resistance magnetic properties

Thermal decomposition kinetics of basic carbonate cobalt nanosheets obtained from spent Li-ion batteries:Deconvolution of overlapping complex reactions

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Transactions of Nonferrous Metals Society of China 2018年第6期28卷 1265-1274页

作者： Hossein EBRAHIMZADE gholam reza khayati Mahin SCHAFFIE Department of Mineral Industries Research Center Shahid Bahonar University of Kerman Department of Materials Science and Engineering Shahid Bahonar University of Kerman Department of Chemical Engineering Shahid Bahonar University of Kerman

A new non-isothermal method of kinetic analysis was employed to investigate the thermal decomposition kinetic modeling of the basic carbonate cobalt nanosheets（n-BCoC） synthesized from spent lithium-ion batteries（LIBs）. Fraser–Suzuki function was applied to deconvoluting overlapping complex processes from the overall differential thermal curves obtained under the linear heating rate conditions, followed by the kinetic analysis of the discrete processes using a new kinetic analysis method. Results showed that the decomposition of n-BCo C in air occurred through two consecutive reactions in the 136-270 ℃ temperature intervals. Decomposition started by hydroxide component（Co（OH）2） decomposition until to 65% and simultaneously carbonate phase decarbonation began. The process was continued by CO2 evolution and finally carbonate cobalt nanosheets have been produced. The reaction mechanism of the whole process can be kinetically characterized by two successive reactions： a phase boundary contracting reaction followed by an Avrami-Erofeev equation. Mechanistic information obtained by the kinetic study was in good agreement with FT-IR（Fourier transform infrared spectroscopy） and SEM（scanning electron microscopy） results.

关键词： kinetic modeling basic carbonate cobalt nanosheets (n-BCoC) overlapping reactions spent lithium-ion battery

Isothermal kinetics of mechanochemically and thermally synthesized Ag from Ag_2O

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Transactions of Nonferrous Metals Society of China 2012年第4期22卷 935-942页

作者： gholam reza khayati Kamal JANGHORBAN Mohamad Hosein SHARIAT Department of Materials Science and Engineering Shahid Bahonar University of KermanKermanIran Department of Materials Science and Engineering School of EngineeringShiraz UniversityZand AvenueShirazIran

The kinetics of isothermal reduction of Ag2O with graphite under argon atmosphere for a non-activated sample and mechanically activated sample was *** is found that Johnson-Mehl-Avrami model appropriately explained the thermal and mechanochemical synthesis of Ag from Ag2O＋ghraphite *** process kinetics was investigated using the same approach for milled and unmilled *** results show that the Avrami exponent of mechanochemical reduction is higher than that of high temperature thermal ***,the mechanisms of nuclei growth in thermal and mechanochemical reduction are diffusion controlled and interface controlled,respectively.

关键词： isothermal kinetics mechanochemical activation thermal reduction Johnson-Mehl-Avrami model Ag

Reaction pathway and kinetics of CdO nanoparticles prepared from CdCO_3 precursor using thermal decomposition method

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Transactions of Nonferrous Metals Society of China 2016年第4期26卷 1138-1145页

作者： gholam reza khayati Seyed Hadi SHAHCHERAGHI Vahid LOTFI Esmael DArezaRESHKI Department of Materials Science and Engineering Shahid Bahonar University of KermanP.O.Box No.76135-133KermanIran Department of Advanced Science and Technology Shahid Bahonar University of KermanP.O.Box No.76135-133KermanIran Mineral Industries Research Centre Shahid Bahonar University of KermanP.O.Box No.76135-133KermanIran

The non-isothermal kinetics of CdO nanoparticles prepared from CdCO3 precursor using thermal decomposition method was investigated. A model-fitting Malek approach and a model-free advanced isoconversional method of Vyazovkin were applied to the analysis of the DSC and TGA data. The results showed that CdO nanoparticles prepared from CdCO3 followed an autocatalytic reaction. Sestak–Berggren model could favorably describe the studied reaction process. Moreover, the apparent activation energy of CdCO3 decomposition was calculated to be (119.19±9.97) kJ/mol and the explicit rate equation form of CdCO3 decomposition was established.

关键词： CdCO_3 CdO nanoparticle kinetic modeling thermal decomposition advanced isoconversional method

Experimental and Finite Element Analysis of Corroded High-Pressure Pipeline Repaired by Laminated Composite

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 1783-1806页

作者： Seyed Mohammad reza Abtahi Saeid Ansari Sadrabadi gholam Hosein Rahimi Gaurav Singh Hamid Abyar Daniele Amato Luigi Federico Faculty of Mechanical Engineering Tarbiat Modares UniversityTehran***Iran A.Leon Linton Department of Mechanical Robotics and Industrial EngineeringLawrence Technological UniversitySouthfieldMI48075USA Department of Mechanical Engineering Faculty of EngineeringMeybod UniversityYazd***Iran Department of Industrial Engineering University of SalernoVia Giovanni PaoloⅡFiscianoItaly Italian Aerospace Research Center(C.I.R.A.) Via MaioriseCapuaCE81043Italy

Repairs of corroded high-pressure pipelines are essential for fluids transportation under high *** of the methods used in their repairs is the use of layered *** composite used must have the necessary ***,the experiments and analytical solutions presented in this paper are performed according to the relevant standards and codes,including ASME PCC-2,ASME B31.8S,ASME B31.4,ISO 24817 and ASME *** addition,the experimental tests are replicated numerically using the finite element *** the strain gauges at different distances from the defect location,can reduce the nonlinear effects,deformation,and fluctuations due to the high *** direct relationship between the depth of an axial defect and the stress concentration is observed at the inner side edges of the *** reparation reduces the non-linearities related to the sharp variation of the geometry and a more reliable numerical simulation could be performed.

关键词： High-pressure pipeline composite repair ASME PCC-2 ISO 24817

Perfect GMR effect in gapped graphene-based ferromagnetic normal ferromagnetic junctions

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Chinese Physics B 2015年第4期24卷 405-410页

作者： Hossein Karbaschi gholam reza Rashedi Department of Physics University of Isfahan

We investigate the quantum transport property in gapped graphene-based ferromagnetic/normal/ferromagnetic （FG/NG/FG） junctions by using the Dirac-Bogoliubov-de Gennes equation. The graphene is fabricated on SiC and BN substrates separately, so carders in FG/NG/FG structures are considered as massive relativistic particles. Transmission prob- ability, charge, and spin conductances are studied as a function of exchange energy of ferromagnets （h）, size of graphene gap, and thickness of normal graphene region （L） respectively. Using the experimental values of Fermi energy in the normal graphene part （EFN - 400 meV） and energy gap in graphene （260 meV for SiC and 50 meV for BN substrate）, it is shown that this structure can be used for both spin-up and spin-down polarized current. The latter case has different behavior of gapped FG/NG/FG from that of gapless FG/NG/FG structures. Also perfect charge giant magnetoresistance is observed in a range of E FN - mv 2 F〈h〈E FN＋mv 2 F.

关键词： graphene spin-polarized current giant magnetoresistance nanoscale structures