Magnetic properties of magnetite nanoparticles prepared by mechanochemical reaction (original) (raw)
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Key Engineering Materials, 2011
In this study, magnetite (Fe3O4) nanoparticles were synthesized at room temperature using FeCl3.6H2O (1.28 M), FeCl2.4H2O (0.64 M) and HCl (0.4 M) for preparing a solution as the iron source and NaOH (0.9-1.5 M) for to prepare a solution as the alkali source by the aqueous phase co-precipitation method under vigorous mechanical stirring (450 and 750 rpm) together with N2 gas flowing through the reaction medium during synthesis operation in closed system. The powder samples were characterized by the commonly used techniques of scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infra-red (FTIR), X-ray diffraction (XRD), vibrating sample magnetometry (VSM) and BET analyses. SEM was used to observe the morphology and agglomeration state of the powder. Size and morphology of the precipitated crystallites were examined with TEM. The prevalence of functional groups in the synthesized powders was ascertained by FTIR spectroscopy. The pure magnetite and other phases according to processing parameters were observed by XRD analysis. The magnetic properties of magnetite (Fe3O4) nanoparticles were examined using VSM. Finally, the specific surface area of nanoparticles was measured by BET technique. The results indicate that smaller particles can be synthesized by increasing stirring rate and decreasing the NaOH concentration, which in this case corresponded to 35 nm using 0.9 M NaOH at 750 rpm. The VSM analysis showed a saturation magnetization range of (82-96 emu/g) and coercivity of (83-119 Oe) for particles between (35-96 nm) respectively. Also, the highest specific surface area of 40 m2/g was obtained at 0.9 M NaOH at 750 rpm and the smallest value of 15 m2/g at 1.5 M of NaOH at 450 rpm using BET analysis.
Synthesis and Characterization of Magnetite Nanoparticles
Smart Energy and Sustainable Environment, 2023
Article info: Magnetite (Fe3O4) nanoparticles have garnered the attention of researchers in the fields of renewable energy, electronics, and medicine over the past decade due to their magnetic and high magnetic susceptibility. The unique properties of magnetite make it an essential material for the development and advancement of renewable technologies. To obtain magnetite powder through hydrothermal synthesis, the precursors used were FeCl2•4H2O and FeCl3•6H2O aqueous solutions with a molar ratio of 1:2, and NaOH solution with a concentration of 2 M was used as the hydrolysis agent. The reaction took place at varying temperatures of 85°C, 150°C, and 200°C, and a pressure of 20 bar. The resulting powders were then subjected to morpho-structural characterization using techniques such as scanning electron microscopy and X-ray diffraction.
Synthesis and characterization of magnetite nanopowders
Current Applied Physics, 2008
Nano-sized magnetite (Fe 3 O 4) nanoparticles were prepared using dry and wet chemical methods in presence of surfactants as capping agents. The samples were characterized by X-ray diffraction, FT-IR, thermal analysis (DTA and TG), Electron microscopy (SEM) as well as (TEM), dynamic laser scattering analyzer (DLS) and vibrating sample magnetometer (VSM) techniques. The X-ray diffraction pattern show cubic spinel crystal structure for all samples. Particle size in the range of 8-55 n m is obtained. The effect of preparation method and γ-irradiation process on the magnetic properties of prepared samples was studied and discussed. All samples show soft-magnetic behavior with much lo wer coerciv ity and much higher saturation magnetization. The coercive force (H c), saturation magnetizat ion (B s), remanent induction (B r) and the rat io of remanent induction to saturation magnetizat ion (B r /B s) are found to be size and shape dependent. The saturation magnetization value lies between 20.5 and 64.5 emu/g. The magnetic properties are exp lained by electron hopping mechanis m between Fe 2+ and Fe 3+-ions. The use of magnetite nanoparticles in preparation of ferrofluid was investigated. The ferroflu id stability increases with decreasing the particle size.
Synthesis and Some Physical Properties of Magnetite (Fe 3 O 4 ) Nanoparticles
Fe 3 O 4 nanoparticles and non aqueous stable magnetic fluid (MF) containing Fe 3 O 4 nanoparticles with mean diameters of 10 nm, which are in the range of super-paramagnetism, are prepared. Magnetite nanoparticles are synthesized via co-precipitation method from ferrous and ferric solutions. X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) are used to study the physical properties of the (MF) and powder. The band gap parameters of the magneto-nanopowders such as the direct, indirect-band gap energies, Fermi energy and Urbach energy are determined.
Properties of magnetite nanoparticles synthesized through a novel chemical route
Materials Letters, 2004
We have developed a simple precipitation route to synthesize magnetite (Fe 3 O 4 ) nanoparticles with controlled size without any requirement of calcination step at high temperatures. The study of these nanoparticles indicates an enhancement in saturation magnetization with reduction in size down to f 10 nm beyond which the magnetization reduces. The latter is attributed to surface effects becoming predominant as surface to core volume ratio increases. From the view-point of applications, 10 nm size of magnetite particles seems to be the optimum. D
Acta Physica Polonica A, 2014
The presented study compares magnetic properties of Ni-doped magnetites Ni 2+ 0.5 Fe 2+ 0.5 Fe 3+ 2 O4 to magnetite (Fe3O4) sample. Physicochemical properties of materials were registered by means of X-ray powder diraction, Mössbauer spectroscopy, saturation magnetization and physical properties measurement systems. It was obtained that used preparation procedures lead to synthesis of single phase spinel materials with close nanodimensional size about 812 nm. Mechanochemically synthesized sample shows better magnetic properties as lower blocking temperature of superparamagnetic state and minimal coercivity in comparison to other studied materials.
A review of Structure, Properties, and Chemical Synthesis of Magnetite Nanoparticles
Journal of applied sciences and nanotechnology, 2023
In recent years, extensive studies have been devoted to iron oxide nanoparticles (IONPs). Iron oxides are chemical compounds that have various polymorphic forms, including maghemite (γ-Fe2O3), magnetite (Fe3O4), and Hematite (α-Fe2O3). Among them, the most important studied is magnetite (Fe3O4) due to its low cost and low toxicity and its unique magnetic and physicochemical characteristics, which qualify it for use in various biomedical and technological applications. Magnetic particles should be small and have a narrow size distribution for these applications. The smaller the size of the iron oxide particles, the greater their reactivity and biodegradability. In this review, we display summary information on magnetite (Fe3O4) nanoparticles in terms of structure, characteristics, and preparation methods. Because the prepared strategy has been proven to be critical for preferable control of the particle size and shape, in addition to producing monodispersed magnetite (Fe3O4) nanoparticles with a direct effect on their characteristics and applications, special attention will be placed on chemical preparation techniques including Hydrothermal synthesis, Coprecipitation technique, Sol-Gel process, and thermal decomposition method. This review offers specific information for selecting appropriate synthetic methods for obtaining appropriate sizes, shapes, and magnetic properties of magnetite (Fe3O4) nanoparticles (NPs) for target applications.
IOP Conference Series: Materials Science and Engineering, 2011
Magnetite (Fe 3-δ O 4 ) nanoparticles with the size less than 30 nm have been synthesized by using a simple reverse co-precipitation method at room temperature. During the process, ferrous sulfate (FeSO 4 •7H 2 O) powder was used as an iron precursor, and ammonium hydroxide (NH 4 OH) as a precipitating agent. The experiment was carried out in ambient atmosphere without any surfactant added. In this method, the base solution for the precipitation process was adjusted to have a pH value suitable for the formation of the magnetite phase. The iron salt precursor was added into the solution during the synthesis by two different synthesis protocols. The phase, morphology and magnetic characteristic of differently synthesized magnetite particles were characterized by using an X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The morphologies of the particles were spherical or irregular in shape depending on the synthesis protocol used. Magnetic measurement shows that the particles are ferromagnetic at room temperature with relatively high saturation magnetization and low hysteresis. The saturation magnetization and magnetic hysteresis of the particles varied with preparation reaction conditions and the resulting oxidation state of the particles.
Nanocrystalline/Nanosized Fe3O4 Powder Obtained by Mechanosynthesis
Advanced Engineering Forum, 2015
Nanocrystalline/nanosized magnetite - Fe3O4 powder was obtained by mechanical milling of well crystallized magnetite obtained by ceramic method starting from stoichiometric mixture of commercial hematite - Fe2O3 and iron - Fe powders. The mean crystallites size of the magnetite is decreasing upon increasing the milling time down to 6 nm after 240 minutes of milling. After 30 minutes of milling an undesired hematite phase is formed in the material. The amount of this phase increases upon increasing the milling time. In the early stage of milling (up to 30 minutes) the existence of nanometric particles (mean size below 100 nm) is noticed. The d50 median diameter decreases first (up to 5 minutes of milling) and after that, an increase follows for milling times up to 120 minutes. Saturation magnetization decreases upon increasing the milling time and is more difficult to saturate. X-ray diffraction, laser particle size analysis and magnetic measurements have been used for powder charact...