ابوالقاسم عطائی
استاد- دانشگاه تهران
[ 1 ] - بررسی رفتار اسپینل منگنز کبالتایت به عنوان پوشش صفحات اتصال دهنده پیل سوختی اکسید جامد
در این پژوهش نانوذرات اسپینلی منگنز کبالتایت (MnCo2O4) با استفاده از روش شیمیایی هم‌رسوبی تهیه شد. نتایج آنالیز پراش پرتو ایکس (XRD) نشان داد که با کلسیناسیون در دمای C˚1000 شکل‌گیری فاز اسپینلی کامل شد. با توجه به تصاویر میکروسکپ الکترونی روبشی (FESEM) از پودرهای ماده اسپینلی مشخص شد که با افزایش دمای کلسیناسیون از 350 به C˚1000، اندازه ذرات با قطر nm 148 و ضخامت nm 18 به ذراتی با اندازه متوسط...
[ 2 ] - La0.6Sr0.4Co0.2Fe0.8O3 perovskite cathode for Intermediate Temperature Solid Oxide Fuel Cells: A comparative study
In this study the characteristics of two different kinds of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) powders, one in-house synthesized powder by a co-precipitation method and another one purchased from Fuel Cell Materials Co. (FCM Co., USA), were compared. The co-precipitated powder was prepared by using ammonium carbonate as precipitant with a NH4+/NO3- molar ratio of 2 and calcination at 1000C for 1 h....
[ 3 ] - Effect of CNT Addition on the Characteristics of Cu-Ni/CNT Nanocomposite
In this study, Cu50-Ni50 alloy were synthesized by mechanical alloying. The alloy was then reinforced by dispersion of multiwalled carbon nanotubes using a planetary high energy ball mill. X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer were used to evaluate the effects of CNT addition on the characteristics of the nanocomposites. XRD results of Cu-Ni sample sh...
[ 4 ] - Chemico- thermal synthesis of nano-structured cobalt with distinct magnetic property
The synthesis of nano- structured cobalt through a controlled chemical process followed by heat treating at various temperatures is studied. The product is characterized by ICP, XRD, FESEM , and TEM, indicating that the as- synthesized particles have an amorphous structure with 1.76 for Co/B ratio, an average size of 50 nm. The transformation of intermediate phases into single phase nano- cryst...
[ 5 ] - Electrode Materials for Lithium Ion Batteries: A Review
Electrochemical energy storage systems are categorized into different types, according to their mechanisms, including capacitors, supercapacitors, batteries and fuel cells. All battery systems include some main components: anode, cathode, an aqueous/non-aqueous electrolyte and a membrane that separates anode and cathode while being permeable to ions. Being one of the key parts of any new electr...
[ 6 ] - Effective enhancement of electrochemical properties of LSM oxygen electrode in SOCs by LNO nano-catalyst infiltration
In this paper, the effects of infiltration of La2NiO4 (LNO) as a mixed ionic and electronic conductor (MIEC) on the electrochemical performance of porous strontium doped lanthanum manganite (LSM) oxygen electrode of solid oxide cells, in the temperature ranges of 650-850 °C, is reported. XRD and FE-SEM results of the LNO sample calcined at 900 °C confirmed the formation of single phase LNO nano...
[ 7 ] - A comparison study of polymer/cobalt ferrite nano-composites synthesized by mechanical alloying route
In this research, the effect of different biopolymers such as polyethylene glycol (PEG) and polyvinylalcohol (PVA) on synthesis and characterization of polymer/cobalt ferrite (CF) nano-composites bymechanical alloying method has been systematically investigated. The structural, morphological andmagnetic properties changes during mechanical milling were investigated by X-ray diffraction (XRD),Fo...
[ 8 ] - Effect of processing parameters on the electrochemical performance of graphene/ nickel ferrite (G-NF) nanocomposite
Fuel cells, secondary batteries and capacitors are among many promising energy storage devices. In particular, supercapacitors have attracted much attention because of their long life cycle and high power density. Graphene/nickel ferrite(G-NF) based supercapacitors were successfully fabricated through a one-step facile solvothermal route. Effects of synthesis conditions i.e. solvothermal time a...
[ 9 ] - Synthesis of Nano-Structured La0.6Sr0.4Co0.2Fe0.8O3 Perovskite by Co-Precipitation Method
Nano-structured lanthanum strontium cobalt ferrite, La0.6Sr0.4Co0.2Fe0.8O3 (LSCF), was successfully synthesized via co-precipitation method using metal nitrates as starting materials. Effects of precipitating agent and calcination temperature on the phase composition and morphology of synthesized powders were systematically studied using X-ray diffraction (XRD) and field emission scanning elect...
[ 10 ] - Characterization of the metastable Cu-Fe nanoparticles prepared by the mechanical alloying route
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 ma...
[ 11 ] - پر عیارسازی کنسانتره تیتانیوم معدن کهنوج به روش سرباره سازی
تحقیق حاضر به منظور پر عیارسازی کنسانتره های معدن تیتانیوم کهنوج , ایلمنیت و تیتانومگنتیت, به روش سرباره سازی و ببرسی چگونگی تأثیر آنها بر نحوه تشکیل و جدایش چدن از سرباره و توزیع عناصر مختلف در آنها, تأثیر اکسیداسیون و استحاله های فازی کنسانتره ها در دمای بالا نیز بر روند فرآیند سرباره سازی مورد بررسی قرار گیرد. نتایج حاصل از این تحقیق نشان دادند که دما و زمان احیاء و ذوب , نوع و میزان مواد ک...
[ 12 ] - تأثیر نوع مواد اولیه بر ترکیب فازی و مورفولوژی پودر مغناطیسی فریت نوع M
در این مقاله امکان تهیه پودر هگزافریت باریم ( ) و هگزافریت استرانسیم ( ) با استفاده از مواد اولیه داخلی مورد بررسی قرار گرفته است. مطالعات انجام شده توسط پراش اشعه X و میکروسکپ الکترونی روبشی(SEM), نشان داده اند که نوع مواد اولیه تأثیر بسزایی در روند تشکیل فاز مغناطیسی فریت و مورفولوژی آن دارد. نتایج حاصل از این کار پژوهشی نشان داد که امکان تهیه پودر فریت در صورت استفاده از سولفات باریم یا سولف...
[ 13 ] - AN INVESTIGATION ON REACTIVE SINTERING OF NANO-CRYSTALLINE TiO2 -Al POWDER PREPARED BY MECHANICAL ALLOYING
In this research an ultra-fine grained composite structure consisting of an intermetallic matrix together with dispersed nano-sized Al2O3 obtained via mechanical activation of TiO2 and Al in a high energy ball mill and sintering of consolidated samples. Phase composition and morphology of the milled and sintered samples were evaluated by XRD and SEM techniques Thermal behavior of the powder sa...
[ 14 ] - Preparation of nano-structured strontium carbonate from Dasht-e kavir celestite ore via mechanochemical method
Strontium carbonate (SrCO3) is one of the most important strontium compounds that have been used in a variety of technological and industrial applications. In the present investigation, nano-structured strontium carbonate was synthesized by mechano-chemical reaction of celestite ore (SrSO4) collected from Dasht-e kavir, Iran and sodium carbonate during high energy mechanical milling.The milling...
[ 15 ] - Synthesis of Three - Dimensional Mesoporous Silicon from Rice Husk via SHS Route
Silicon nanoparticles are the focus of attention thanks to their potentialities in advanced applications such as new batteries, photovoltaic cells and so on. The need to porous silicon is thus rising and will follow the same trend. In this work, highly porous nanostructured silicon is synthesized via Self-propagating high-temperature synthesis (SHS) route. Microstructural and phase analyses sho...
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