scholarly journals Structure and Magnetic Properties Of Fe/Si Nanoparticles Prepared by High Energy Milling Process

2021 ◽  
Vol 11 (2) ◽  
pp. 239
Author(s):  
Muhammad Rifai ◽  
Yunasfi Yunasfi ◽  
Engkir Sukirman ◽  
Yosef Sarwanto ◽  
Mujamilah Mujamilah
Keyword(s):  
Phase Transition ◽  
Particle Size ◽  
Magnetic Properties ◽  
Iron Oxides ◽  
High Energy ◽  
Milling Process ◽  
Particle Size Reduction ◽  
High Energy Milling ◽  
Si Nanoparticle ◽  
Si Nanoparticles

The structure and magnetic properties of Fe/Si nanoparticle prepared by high energy milling process have been examined, focusing on the phase transition. Fe/Si nanoparticles were processed by high energy milling (HEM) for 10 hours to 50 hours with a weight per cent ratio of 9:1. Based on the X-ray diffraction (XRD) pattern, transmission electron microscope (TEM) observations, and vibrating sample magnetometer (VSM) analysis, the phase transition induced by HEM, were evidenced. The effect of structural state and the particle size on the magnetic properties such as magnetization was also studied. It was found that iron and iron oxides (-Fe2O3/ Fe3O4) phase were exhibited on all milled samples. The magnetization value of Fe/Si nanoparticles increased up to 20 hours with 142 emu/gr saturated magnetization and then decreased linearly with increasing milling time. Referring to the XRD result, this decline was initially caused by the iron oxide formation and magnetic interaction between iron and iron oxides nanoparticles. The phase and magnetic properties value changes related to the interaction mechanism between Fe atoms caused by interstitial occupied of Si atoms, particle size reduction, and oxidation process.

scholarly journals New Aspects of MgH2 Morphological and Structural Changes during High-Energy Ball Milling

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4550
Author(s):  
Tomasz Czujko ◽  
Ewelina E. Oleszek ◽  
Mariusz Szot
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Powder Particle ◽  
Structural Changes ◽  
High Energy ◽  
Decomposition Temperature ◽  
Milling Process ◽  
Size Analysis ◽  
Crystallographic Structure ◽  
Particle Size Reduction

Magnesium hydride, despite the decomposition temperature being incompatible with the operating temperature of a typical PEM cell, is still considered a prospective material for hydrogen storage. Hence, this paper presents new aspects of the influence of milling time on the structural changes and temperature of MgH2 decomposition, with particular emphasis on the changes taking place in the first few seconds of the milling process. This paper presents qualitative and quantitative changes in the powder particle morphology determined using scanning electron microscopy (SEM) and infrared particle size analysis (IPS) systems. The crystallographic structure of the powders in the initial state and after mechanical milling was characterized by X-ray diffraction. The decomposition temperature and activation energy were determined by the differential scanning calorimetry (DSC). Changes in the activation energy and decomposition temperature were observed after only 1–2 min of the milling process. Two basic stages of the milling process were distinguished that impacted the MgH2 decomposition temperature, i.e., mechanical activation and a nanostructuring process. The activation was associated with the initial stage of particle size reduction and an increase in the fraction of fresh chemically active powder particle surfaces. On the other hand, the nanostructuring process was related to an additional decrease in the MgH2 decomposition temperature.

Electrochemical Properties of LiFePO4/C Composite Improved by High Energy Milling

2009 ◽  
Vol 620-622 ◽  
pp. 41-44 ◽  
Author(s):  
Chang Sam Kim ◽  
Sung Ik Hwang ◽  
Shin Woo Kim
Keyword(s):  
Particle Size ◽  
Electrochemical Properties ◽  
Sucrose Solution ◽  
Ultrasonic Spray Pyrolysis ◽  
Lithium Ion ◽  
High Energy ◽  
Milling Process ◽  
Spray Pyrolysis Method ◽  
High Energy Milling ◽  
Ultrasonic Spray

The electrochemical properties of LiFePO4 as a cathode of lithium ion batteries considerably depend on a particle size of LiFePO4 and a condition of carbon coating. In this study, LiFePO4 powders were prepared using ultrasonic spray pyrolysis method, and then LiFePO4/C composites were made by infiltrating sucrose solution into LiFePO4 powders, drying, high-energy milling and annealing. The effects of high-energy milling were analyzed by comparing with electrochemical properties of powders synthesized without high-energy milling. It was found that the milling process drastically reduced the particle size of synthesized powders and electrical conductivity, and improved discharge capacity, cycle stability and rate performance.

scholarly journals Ultrafast Particle Size Reduction of Fe73.9Si15.5Cu1Nb3B6.6 by High-Energy Milling: Nb2O5 as a Marker of Permeability Enhancement and Magnetic Hardening

2020 ◽  
Vol 2 (5) ◽  
pp. 1484-1496 ◽  
Author(s):  
Jesús López-Sánchez ◽  
Elena Navarro ◽  
Aída Serrano ◽  
Cecilia Granados-Miralles ◽  
Adolfo del Campo ◽  
...  
Keyword(s):  
Particle Size ◽  
High Energy ◽  
Size Reduction ◽  
Particle Size Reduction ◽  
High Energy Milling ◽  
Permeability Enhancement ◽  
Magnetic Hardening

Magnetic properties of nanocrystalline Fe–Co alloys by high-energy milling

2004 ◽  
Vol 377 (1-2) ◽  
pp. 202-206 ◽  
Author(s):  
Yongsheng Liu ◽  
Jincang Zhang ◽  
Liming Yu ◽  
Guangqiang Jia ◽  
Chao Jing ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
High Energy ◽  
High Energy Milling ◽  
Co Alloys

Effect of (Ni, Zn)Ru mixtures on magnetic properties of barium hexaferrites yielded by high-energy milling

2005 ◽  
Vol 285 (3) ◽  
pp. 450-455 ◽  
Author(s):  
A. González-Angeles ◽  
G. Mendoza-Suárez ◽  
A. Grusková ◽  
J. Lipka ◽  
M. Papánová ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
High Energy ◽  
Barium Hexaferrites ◽  
High Energy Milling

Structure, Magnetic and Microwave Properties of Granular Fex(SiO2)1-x Alloys Obtained by Mechanochemical Synthesis

2012 ◽  
Vol 190 ◽  
pp. 585-588
Author(s):  
S.F. Lomayeva ◽  
A.N. Maratkanova ◽  
Konstantin N. Rozanov ◽  
D. A. Petrov ◽  
Eugene P. Yelsukov
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Domain Walls ◽  
Magnetic Loss ◽  
Structural Phase ◽  
High Energy ◽  
Microwave Properties ◽  
Particle Size Reduction ◽  
Milling Medium ◽  
Energy Ball

The structural-phase composition, magnetic and microwave properties of Fex(SiO2)1-x (x=30, 70, 90, 95) nanocomposites have been studied. The composites are produced by high-energy ball milling with either Ar or acetone as a milling medium and milling time of 1 to 64 h. The microwave magnetic properties of the composite in the frequency range of 0.1 to 6 GHz are shown to depend slightly on the phase composition and be governed mainly by the particle size. Reduction of the particle size to about 1 μm results in elimination of magnetic loss at frequencies below 1 GHz, which is attributed to the domain walls motion.

High Energy Milling of WС-FeСr Cemented Carbide

2019 ◽  
Vol 799 ◽  
pp. 136-141
Author(s):  
Marek Tarraste ◽  
Jakob Kübarsepp ◽  
Kristjan Juhani ◽  
Märt Kolnes ◽  
Mart Viljus
Keyword(s):  
Particle Size ◽  
Ball Mill ◽  
Size Range ◽  
High Energy ◽  
Cemented Carbide ◽  
Cemented Carbides ◽  
Binder Phase ◽  
Metal Powders ◽  
Powder Mixtures ◽  
High Energy Milling

During production of cemented carbides hard and brittle tungsten carbide (WC) and ductile metal powders (mainly from Fe-group) are milled together. Complete milling results in a Gaussian distribution and narrow particle size range of the milled powder which promote the homogeneity and improve the properties of sintered composites. Cobalt, conventional metal employed in cemented carbides, possesses good comminution characteristics with WC powder. However, its toxicity and fluctuating price pushes researchers to find suitable alternatives and Fe-based alloys have shown most promising results. Cemented carbides with the Fe-Cr system as metal binder phase have potential to perform better than regular WC-Co composites in corrosive and oxidative environments. The goal of this paper was to prepare uniform cemented carbides powders with relatively high fraction of stainless Fe-Cr steel. To achieve a uniform powder mixture is a challenge at high ductile steel fraction. High energy milling (HEM) is a powerful technique for achieving (ultra) fine powder mixtures with narrow powder size range. HEM was carried out in a novel high energy ball mill RETSCH Emax. Milling in tumbling ball mill, which is the most widely used method, was employed for reference. Prepared powder mixtures were characterised in terms of particle size, size distribution and shape. In addition, powder mixtures were consolidated via spark plasma sintering to evaluate the effect of the milling method and the duration on the microstructure of final cemented carbide.

Fabrication of Al–20wt%Si powder using scrap Si by ultra high-energy milling process

2012 ◽  
Vol 536 ◽  
pp. S45-S49 ◽  
Author(s):  
Won-Kyung Kang ◽  
Fikret Yılmaz ◽  
Hyo-Seob Kim ◽  
Jar-Myung Koo ◽  
Soon-Jik Hong
Keyword(s):  
High Energy ◽  
Milling Process ◽  
Ultra High Energy ◽  
High Energy Milling

Preparation of Nb-40Ti Powders by High-Energy Milling

2005 ◽  
Vol 498-499 ◽  
pp. 146-151
Author(s):  
Y.A. Giffoni ◽  
Erika Coaglia Trindade Ramos ◽  
Ana Sofia Ramos ◽  
Hugo Ricardo Zschommler Sandim ◽  
M.T.T. Pacheco
Keyword(s):  
Solid Solution ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
High Energy Milling ◽  
Porous Ti ◽  
Titanium Hydride Powder ◽  
Tih2 Powder ◽  
Ti Powder

Porous Ti-Nb alloys are promising candidates for biomedical applications. In the present study, alloy powders containing 60 wt-% Nb were prepared by high-energy milling of Nb, Ti, and/or TiH2 powders. The high-energy milling process was carried out in a planetary ball mill. The starting and as-milled materials were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). Elemental (Nb, and Ti) and TiH2 powder mixtures with composition Nb-40wt%Ti were mechanically alloyed for 2 to 30 h. The formation of a BCC Nb(Ti) solid solution by high-energy milling using elemental Ti powder to produce Nb-40Ti was observed after milling for 30 h. A HCP-Ti solid solution was formed after milling for 30 h due to the partial decomposition of titanium hydride powder mixture during high-energy milling.

SYNTHESIS OF THE NANOCRYSTALLINE NICKEL FERRITE BY A NOVEL MECHANO SOL–GEL AUTO-COMBUSTION METHOD

2011 ◽  
Vol 25 (11) ◽  
pp. 855-861 ◽  
Author(s):  
M. SHAHMIRZAEI ◽  
S. A. SEYYED EBRAHIMI ◽  
R. DEHGHAN
Keyword(s):  
Nickel Ferrite ◽  
Single Phase ◽  
Sol Gel ◽  
Combustion Method ◽  
High Energy ◽  
Milling Process ◽  
Nanocrystalline Powder ◽  
High Energy Milling ◽  
Metal Nitrates ◽  
Auto Combustion

In this work, a novel method of mechano sol–gel auto-combustion has been developed for production of single phase nickel ferrite nanocrystalline powder, consisting of a sol–gel auto-combustion synthesis followed by a high energy milling process before calcination. Sol–gel auto-combustion was carried out using a gel including citric acid as a reductant and metal nitrates as oxidants. This gel exhibited a self-propagating behavior after ignition in air. The effects of the intermediate high energy milling on the physical properties of the final product after calcination were investigated. The results showed that with a high energy milling of the sol–gel auto-combusted powders with a ball-to-powder mass ratio of 20 for 20 h, the temperature of calcination for synthesis of the single phase ferrite reduced from 1000°C to 700°C and the size of the ferrite crystallites decreased from 72 nm to 15 nm.

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