scholarly journals Impact of Gadolinium on the Structure and Magnetic Properties of Nanocrystalline Powders of Iron Oxides Produced by the Extraction-Pyrolytic Method

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4147
Author(s):  
Vera Serga ◽  
Regina Burve ◽  
Mikhail Maiorov ◽  
Aija Krumina ◽  
Ramūnas Skaudžius ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Thermal Treatment ◽  
Iron Oxides ◽  
Caproic Acid ◽  
Transformation Process ◽  
Nanocrystalline Powders ◽  
Preparation Conditions ◽  
Oxide Phases

Interest in magnetic nanoparticles is primarily due to their practical use. In this work, for the production of nanocrystalline powders of pure and gadolinium doped iron oxides, the extraction-pyrolytic method (EPM) was used. As a precursor, either iron-containing extract (iron (III) caproate in caproic acid) or its mixture with gadolinium-containing extract (gadolinium (III) valerate in valeric acid) was used. The mixed precursor contained 0.5 mol %, 2.5 mol %, 12.5 mol %, 50 mol %, and 75 mol % gadolinium in relation to the iron content. The formation of iron oxide phases, depending on the preparation conditions, was investigated. According to the results obtained, it was demonstrated that the presence of more than 2.5 mol % gadolinium additive in the mixed precursor inhibits the magnetite-to-hematite transformation process during thermal treatment. Produced samples were characterized by XRD and SEM methods, and the magnetic properties were studied.

Effect of aluminum doped iron oxide nanoparticles on magnetic properties of the polyacrylonitrile nanofibers

2017 ◽  
Vol 37 (2) ◽  
pp. 135-141
Author(s):  
Armin Ourang ◽  
Soheil Pilehvar ◽  
Mehrzad Mortezaei ◽  
Roya Damircheli
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Iron Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Negative Interaction ◽  
Magnetic Nanofibers

Abstract In this work, polyacrylonitrile (PAN) was electrospun with and without magnetic nanoparticles (aluminum doped iron oxide) and was turned into magnetic nanofibers. The results showed that nanofibers diameter decreased from 700 nm to 300 nm by adding nanoparticles. Furthermore, pure PAN nanofibers were indicated to have low magnetic ability due to polar bonds that exist in their acrylonitrile groups. Obviously by adding only 4 wt% of the nanoparticles to PAN nanofibers, magnetic ability soared by more than 10 times, but at a higher percentage, it was shown to change just a little due to negative interaction among nanoparticles. This event relates to antiferromagnetically coupling of nanoparticles due to incomplete dispersion at higher percentage.

scholarly journals The Influence of Synthesis Parameters on Structural and Magnetic Properties of Iron Oxide Nanomaterials

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 85 ◽  
Author(s):  
Laura Madalina Cursaru ◽  
Roxana Mioara Piticescu ◽  
Dumitru Valentin Dragut ◽  
Ioan Albert Tudor ◽  
Victor Kuncser ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Crystalline Phase ◽  
Annealing Treatment ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Order Of Magnitude

Magnetic iron oxides have been used in biomedical applications, such as contrast agents for magnetic resonance imaging, carriers for controlled drug delivery and immunoassays, or magnetic hyperthermia for the past 40 years. Our aim is to investigate the effect of pressure and temperature on the structural, thermal, and magnetic properties of iron oxides prepared by hydrothermal synthesis 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, the results obtained by Mössbauer characterization are in excellent agreement with X-ray diffraction and optical microscopy characterization, showing that, for lower pressure values (<100 bar), hematite is formed, while, at pressures >100 bar, the major crystalline phase is goethite. In addition, thermal analysis results are consistent with particle size analysis by X-ray diffraction, confirming the crystallization of the synthesized iron oxides. One order of magnitude higher magnetization has been obtained for sample synthesized at 1000 bar. The same sample provides after annealing treatment, the highest amount of good quality magnetite leading to a magnetization at saturation of 30 emu/g and a coercive field of 1000 Oe at 10 K and 450 Oe at 300 K, convenient for various applications.

scholarly journals CONVERSION OF COAL FLY ASH TO ZEOLITE-BASED IRON OXIDE MAGNETIC NANOCOPOSITES BY MODIFIED FUSION-HYDROTHERMAL SYNTHESIS

2020 ◽  
pp. 30-35
Author(s):  
Silviya Boycheva ◽  
Denitza Zgureva
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Fly Ash ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Coal Ash ◽  
Low Temperature Processing ◽  
Oxide Phases ◽  
Stage Synthesis

Coal fly ash generated in Thermal Power Plants is utilized for synthesis of zeolites due to its aluminosilicate composition. The highest degree of zeolitization of coal ash in a particular zeolite phase is achieved by double-stage synthesis involving successive alkaline melting and hydrothermal activation of the reaction mixtures, while the uniform distribution of the iron oxides transferred from the raw coal ash is ensured by ultrasonic treatment. However, the applied melting step results in the oxidation of the magnetic iron oxide phases to non-magnetic ones, which results in the loss of magnetic properties of the resulting materials. The present investigation focuses on an improved double- stage synthesis procedure by the addition of raw coal ash containing magnetite between high temperature and low temperature processing. In this way, the magnetic phase is retained in the final product and the magnetic properties of the zeolites are preserved, which is important for their application in the adsorption of pollutants from wastewater.

scholarly journals Synthesis of an Anticorrosive Pigment by Thermal Treatment of Iron Oxides from Steel Industry Wastes

2019 ◽  
Vol 28 (52) ◽  
pp. 43-58
Author(s):  
María Angélica Colpas-Ruiz ◽  
Camilo Gnecco-Molina ◽  
Gabriel Antonio Jiménez-Rodríguez ◽  
José Andrés Pérez-Mendoza ◽  
Óscar Fabián Higuera-Cobos
Keyword(s):  
Iron Oxide ◽  
Thermal Treatment ◽  
Iron Oxides ◽  
Steel Industry ◽  
Powder Steel ◽  
Total Iron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Industry Waste ◽  
Different Temperatures

This work reports the obtaining of an anticorrosive pigment composed mainly of hematite (ɑ-Fe2O3) from a powder steel industry waste from rust scale of rebar steel. This residue is mainly composed of Fe2O3 (87.97 %), SiO2 (6.13 %), CaO (1.88 %), Al2O3 (1.30%) and MnO (0.77 %). The total iron oxide of the residue is constituted by the following crystalline phases: magnetite, maghemita, lepidocrocita, wüstite, goethite and hematite. The production of a pigment with a high content of hematite was possible thanks to the high content of precursor iron oxides, which were calcined at different temperatures (750-850 °C) and holding times (0.5-1.50 h). For characterizing the iron content chemically and to identify their iron oxides phases, it was used X-ray fluorescence (XRF) and X-ray diffraction (XRD). The results showed that the pigment with the highest amount of hematite (ɑ-Fe2O3) was obtained at a calcination temperature of 850 °C and a holding time of 1.00 h.

Effects of Zr substitution on structural, morphological, and magnetic properties of bismuth iron oxide phases

2017 ◽  
Vol 26 (8) ◽  
pp. 087502
Author(s):  
A Asif ◽  
M Hassan ◽  
S Riaz ◽  
S Naseem ◽  
SS Hussain
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Bismuth Iron Oxide ◽  
Oxide Phases

scholarly journals Magnetic properties of surface sediments in Schirmacher Oasis, East Antarctica: spatial distribution and controlling factors

2020 ◽  
Author(s):  
Anish Kumar Warrier ◽  
Joju George Sebastian ◽  
K. Amrutha ◽  
A. S. Yamuna Sali ◽  
B. S. Mahesh ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Grain Size ◽  
Magnetic Properties ◽  
Spatial Distribution ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Remanent Magnetization ◽  
Principal Component ◽  
East Antarctica ◽  
Schirmacher Oasis

Abstract Purpose We investigated the magnetic properties (abundance, grain size, and mineralogy) of iron oxides present in Lake L-55 sediments, Schirmacher Oasis, East Antarctica, with an aim to understand their spatial distribution and the underlying mechanisms that control their formation and distribution. Methods Twenty-five surficial sediments retrieved from different parts of Lake L-55 were subjected to the entire range of environmental magnetic (magnetic susceptibility, anhysteretic remanent magnetization (ARM), isothermal remanent magnetization (IRM)) measurements (at different field strengths). Inter-parametric ratios (χARM/SIRM, χARM/χlf, χARM/χfd, IRM20 mT/SIRM, IRM20 mT/ARM, S-ratio, L-ratio) provided insights into the magnetic properties (abundance, grain size, and mineralogy of iron oxides). Scanning electron microscopic-energy dispersive X-ray spectroscopic (SEM-EDS) analysis was performed on magnetic extracts from a few sediments. Besides, organic matter (%) was also calculated for the sediment samples. Principal component analysis was performed to gain information on the presence of different components and their relative dominance. Results The iron oxides are strongly magnetic (high values of concentration-dependent parameters). The principal iron oxide is magnetite (S-ratio > 0.90) which is coarse-grained (multi-domain (MD) and stable single-domain (SSD) grains), and there is no influence of authigenic greigite, bacterial magnetite, and anthropogenic magnetite. The mineralogy is confirmed by SEM-EDS data. The iron oxides are of different grain sizes, and their contribution is in the order of MD > SSD > SP as shown by the principal component analysis. Pedogenic iron oxide minerals seem to be present in the samples whose formation is due to the oxidation of magnetite into hematite. However, they are of SSD size and not SP, suggesting that the intensity of pedogenesis is not sufficient to form SP grains. Conclusion The iron oxide minerals are mainly terrigenous, and the biogenic activity within the lake is not sufficient to modify the ferrimagnetic minerals. Spatial distribution patterns suggest the non-uniform distribution of magnetite/titanomagnetite of varying sizes in the lake basin which is transported by both melt water streams and winds.

scholarly journals Methods of Synthesis of Nanodispersed Iron Oxides

2015 ◽  
Vol 16 (1) ◽  
pp. 193-201
Author(s):  
A. B. Hrubiak ◽  
V. О. Kotsyubynsky ◽  
V. V. Moklyak
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Universal Method ◽  
Chemical Methods ◽  
Methods Of Synthesis ◽  
The Relationship

The paper deals with the classification and analysis of main chemical methods of nanostructure iron oxide synthesis. Literature data are systematizated to select a universal method for revealing the relationship between the conditions of synthesis and structural, morphological and magnetic properties of nanomaterials.

Controlling magnetic properties of iron oxide nanoparticles using post-synthesis thermal treatment

2013 ◽  
Vol 114 (2) ◽  
pp. 537-544 ◽  
Author(s):  
Vineet Panchal ◽  
Upendra Bhandarkar ◽  
Manoj Neergat ◽  
K. G. Suresh
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Thermal Treatment ◽  
Iron Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Post Synthesis

The Effect of Stoichiometry of Iron (II) and (III) and Magnetite Oxides on the Kinetic Regularities of their Dissolution in Orthophosphoric Acid Containing Fe (II) and Fe (III) Ions

2019 ◽  
pp. 104-113
Author(s):  
A.V. Kuzin ◽  
I.G. Gorichev ◽  
E.A. Eliseeva ◽  
L.E. Slynko
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Electrolyte Solution ◽  
Orthophosphoric Acid ◽  
Inhibitory Effect ◽  
Electrode System ◽  
Stationary Potential ◽  
Oxide Phases ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

The kinetics of dissolution of iron oxides FeO, α-Fe2O3 and Fe3O4 in orthophosphoric acid, including those containing additions of Fe (II) and Fe (III) ions (in the form of perchlorates), has been studied. The values of the stationary potential in the magnetite electrode system--solutions of orthophosphoric acid, including those containing additions of Fe (II) and Fe (III) ions are determined. The dissolution of Fe3O4 in orthophosphoric acid has been studied and described. Based on the experimental results, it was established that the stimulating and inhibitory effect of Fe (II) and Fe (III) ions is related to their effect on the value of the potential at the boundary of the iron oxide phases/electrolyte solution. The orders of reactions for ions Fe (II), Fe (III) and H3PO4 are determined

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