Magnetic iron oxides nanoparticles obtained by mechanochemical reactions from different solid precursors (original) (raw)
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Magnetic properties of magnetite nanoparticles prepared by mechanochemical reaction
Materials Letters, 2006
Nanosized magnetite (Fe 3 O 4) powders were synthesized via a mechanochemical reaction. Ball milling of 1.2FeCl 2 + 2FeCl 3 + 8.4NaOH led to a mixture of Fe 3 O 4 and NaCl. To avoid agglomeration, the excess NaCl was added to the precursor before ball milling. To prepare different size of particles, the as-milled powders were annealed at temperatures ranging from 100 to 800°C for 1 h in 10% H 2 /Ar mixed gas. Single phase Fe 3 O 4 powders were obtained after removing the NaCl from the as-milled or heated powders. The average crystallite size of the powders varied from 12.5 to 46 nm by changing the annealed temperatures and the corresponding saturation magnetization (σ S) value ranged from 52 to 66.4 emu/g. The coercivity (H c) first increases as the crystallite size decreases, reaches a maximum value of 110 Oe at 22.2 nm and then decreases for any further decrease in particle size.
Synthesis, Characterization and Applications of Magnetic Iron Oxide Nanostructures
Arabian journal for science and engineering, 2017
Iron oxide is a mineral compound that shows different polymorphic forms, including hematite (α-Fe 2 O 3), magnetite (Fe 3 O 4) and maghemite (γ-Fe 2 O 3). Solid propulsion technology nanoparticulate materials, such as hematite and maghemite, exhibit high performance on thermal decomposition of ammonium perchlorate. The enhanced catalytic effect of metallic iron oxide nanoparticles is attributed to their particle size, more active sites and high surface area, which promotes more gas adsorption during thermal oxidation reactions. Nowadays, metallic iron nanoparticles can be synthesized via numerous methods, such as co-precipitation, sol-gel, microemulsion, or thermal decomposition. Although there are data on these synthetic methods in the literature, there is a lack of details related to nanoparticulate oxides and to their characterization techniques. In this context, this short review based on scientific papers, including data from the last two decades, presents methods for obtaining nanoparticulate iron oxides as well as the main aspects of the different characterization techniques and also about the decomposition aspects of these nanomaterials. Morphologies and structures of iron oxides can be characterized through transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, and Fourier transform infrared spectroscopy. As for textural properties, they are usually determined by physical adsorption techniques.
2019
Magnetic iron oxide particles are used for in vitro diagnostics for nearly 40 years. Due to their unique physical, chemical, thermal and mechanical properties, as well as biocompatibility and low toxicity in the human body, iron oxide nanoparticles have been used in many biomedical applications, such as contrast agents for magnetic resonance imaging, carriers for controlled drug delivery and immunoassays, but also in magnetic hyperthermia. Our aim is to investigate the effect of pressure and temperature on the structural, thermal and magnetic properties of iron oxide nanomaterials prepared by hydrothermal synthesis. Iron oxide nanoparticles were synthesized at temperatures of 100-200°C and pressures of 20-1000 bar. It has been found that pressure influences the type of iron oxide crystalline phase. Thus, for lower pressure values (< 100 bar), iron oxide is predominantly formed as hematite, while at pressures > 100 bar, the major crystalline phase is goethite. The complex therm...
ChemistryOpen, 2018
We report an environmentally benign and cost-effective method to produce Fe and Co magnetic metal nanoparticles as well as the Fe/Cao and Co/CaO nanocomposites by using a novel, dry mechanochemical process. Mechanochemical milling of metal oxides with a suitable reducing agent resulted in the production of magnetic metal nanoparticles. The process involved grinding and consequent reduction of low-costing oxide powders, unlike conventional processing techniques involving metal salts or metal complexes. Calcium granules were used as the reducing agent. Magnetometry measurements were performed over a large range of temperatures, from 10 to 1273 K, to evaluate the Curie temperature, blocking temperature, irreversibility temperature, saturation magnetization, and coercivity. The saturation magnetizations of the iron and cobalt nanoparticles were found to be 191 and 102 emu g, respectively. The heating abilities of these nanoparticles suspended in several liquids under alternating magneti...
Magnetic Iron Oxide Nanoparticles: Various Preparation Methods and Properties
This review shows the research on magnetic nanoparticles on their types of production, specific methods for preparing magnetic nanoparticles and properties. Substantial progress has been made for the preparation of magnetic nanoparticles, a major challenge is to find out the most efficient and economical one. At present ferrite nanoparticles and oxide nanoparticles are the most employed one.
2018
Magnetic nanoparticles (MNPs) of iron oxide (Fe3O4) represent the most promising materials in many applications. MNPs have been synthesized by co-precipitation of ferric and ferrous ions in alkaline solution. Two methods of synthesis were conducted with different parameters, such as temperature (25 and 80 C), adding a base to the reactants and the opposite process, and using nitrogen as an inert gas. The product of the first method (MNPs-1) and the second method (MNPs-2) were characterized by x-ray diffractometer (XRD), Zeta Potential, atomic force microscope (AFM) and scanning electron microscope (SEM). AFM results showed convergent particle size of (MNPs-1) and (MNPs-2) with (86.01) and (74.14) nm respectively. Also, the zeta potential values of (MNPs-1) and (MNPs-2) were (2.77) and (-12.48) mV, respectively, which indicates more stability of (MNP-2).
Low Temperature Synthesis of Magnetite and Maghemite Nanoparticles
Journal of Nanoscience and Nanotechnology, 2007
We report on the synthesis of iron oxide nanoparticles below 100 °C by a simple chemical protocol. The uniqueness of the method lies in the use of Ferrous ammonium sulphate (in conjugation with FeCl3) which helps maintain the stability of Fe2+ state in the reaction sequence thereby controlling the phase formation. Hexamine was added as the stabilizer. The nanoparticles synthesized at three different temperatures viz, 5°, 27°, and 95 °C are characterized by several techniques. Generally, when a mixture of Fe3+ and Fe2+ is added to sodium hydroxide, α-Fe2O3 (the anti-ferromagnetic phase) is formed after the dehydration process of the hydroxide. In our case however, the phases formed at all the three temperatures were found to be ferro (ferri) magnetic, implying modification of the formation chemistry due to the specifics of our method. The nanoparticles synthesized at the lowest temperature exhibit magnetite phase, while increase in growth temperature to 95 °C leads to the maghemite p...
EFFECT OF ANNEALING ON STRUCTURAL AND MAGNETIC PROPERTIES OF IRON OXIDE NANOPARTICLES
Nanocrystalline Fe3O4 particles were synthesized by a facile chemical route and annealed at different temperatures in argon atmosphere. The material is then characterized by X-ray diffraction technique (XRD) and dc magnetization measurements. The X-ray diffraction patterns confirm the synthesis of single crystalline phase of Fe3O4 nanoparticles. On annealing at 300oC there is improvement in the crystal structure. A phase transition from magnetite (Fe3O4) to hematite (-Fe2O3) is observed when the samples are annealed above 500oC. The magnetic measurements show superparamagnetic nature of the as-synthesized sample, whereas for annealed samples ferromagnetic nature is observed. The saturation magnetization decreases after phase transition.
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.
Magnetic iron oxide nanoparticles
A new approach to thermal decomposition of organic iron precursors is reported, which results in a simpler and more economical method to produce well crystallized γ -Fe 2 O 3 nanoparticles (NPs) with average sizes within the 3-17 nm range. The NPs were characterized by TEM, SAED, XRD, DLS-QELS, Mössbauer spectroscopy at different temperatures, FT-IR and magnetic measurements. The obtained γ -Fe 2 O 3 NPs are coated with oleic acid and, in a lower quantity, with oleylamine (about 1.5 nm in thickness). It was shown that changing operative variables allows us to tune the average particle diameters and obtain a very narrow or monodisperse distribution of sizes. The γ -Fe 2 O 3 NPs behave superparamagnetically at room temperature and their magnetization saturation is reduced by about 34% in comparison with bulk maghemite. The results indicate that the distance between two neighbour NPs, generated by the coating, of about 3 nm is insufficient to inhibit interparticle magnetic interactions when the average diameter is 8.8 nm. The good quality of the NPs, obtained through the present low-cost and easy-handling process, open a new perspective for future technological applications.