scholarly journals The influence of mechanochemical activation and thermal treatment on magnetic properties of the BaTiO3-FexOy powder mixture

2015 ◽  
Vol 47 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Z. Ristanovic ◽  
A. Kalezic-Glisovic ◽  
N. Mitrovic ◽  
S. Djukic ◽  
D. Kosanovic ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxides ◽  
Powder Mixture ◽  
Mechanochemical Activation ◽  
Total Sample ◽  
Xrd Analysis ◽  
Activation Time ◽  
Solid State Reaction Technique ◽  
Content Change ◽  
Maximum Magnetization

Powder mixture of 50 mass % of barium titanate (BaTiO3) and 50 mass % of iron (Fe) was prepared by solid-state reaction technique, i.e. ball milled in air for 60 min, 80 min, 100 min, 120 min and 150 min. During mechanochemical activation it was observed the iron powder transitsion to iron oxides. Depending on the activation time the content of iron oxides FeO, Fe2O3 and Fe3O4 varies. Simultaneously, with the content change of the activated system, magnetic properties change as well. The XRD analysis of milled samples shown that as the activation time increase, the iron oxide percentage increases to, whereby the percentage of BaTiO3 in a total sample mass decreases. The percentage of iron oxides and BaTiO3 in annealed samples changes depending on annealing temperature. The thermomagnetic measurements performed by Faraday method shown that the powder mixture milled for 100 minutes exhibit maximum magnetization prior to annealing. The increase of magnetization maximum was observed after annealing at 540?C with all milled samples, and at room temperature it has enhancement from 10 % to 22 % depending on the activation time. The samples milled for 100 min and 150 min and then sintered at 1200w?C exhibit magnetoelectric properties.

scholarly journals Morphology and Magnetic Properties of Ferriferous Two-Phase Sodium Borosilicate Glasses

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Alexander Naberezhnov ◽  
Nadezda Porechnaya ◽  
Viktor Nizhankovskii ◽  
Alexey Filimonov ◽  
Bernard Nacke
Keyword(s):  
Magnetic Properties ◽  
Iron Oxides ◽  
Channel Structure ◽  
Borosilicate Glasses ◽  
Melt Quenching ◽  
Two Phase ◽  
Furnace Charge ◽  
Self Assembling ◽  
Quenching Method ◽  
Drop Structure

This contribution is devoted to the study of morphology and magnetic properties of sodium borosilicate glasses with different concentrations (15, 20, and 25 wt.%) ofα-Fe2O3in an initial furnace charge. These glasses were prepared by a melt-quenching method. For all glasses a coexistence of drop-like and two-phase interpenetrative structures is observed. The most part of a drop structure is formed by self-assembling iron oxides particles. All types of glasses demonstrate the magnetic properties and can be used for preparation of porous magnetic matrices with nanometer through dendrite channel structure.

GROWTH, OPTICAL AND MAGNETIC PROPERTIES OF Co-DOPED TiO2 CRYSTAL

2011 ◽  
Vol 04 (03) ◽  
pp. 265-269 ◽  
Author(s):  
NAIFENG ZHUANG ◽  
RONGFENG WANG ◽  
XIAOLIN HU ◽  
CAIGEN SONG ◽  
BIN ZHAO ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Room Temperature ◽  
Grown Crystal ◽  
Reverse Flow ◽  
Optical Transmittance ◽  
Xrd Analysis ◽  
Rutile Phase ◽  
Czochralski Growth ◽  
Optical And Magnetic Properties ◽  
Co Doped

Co -doped TiO2 crystals (Co:TiO2) were grown by Czochralski growth (CZ) method and the edge-defined film-fed growth (EFG) method, respectively. Therein, EFG was an effective method to grow a higher quality Co:TiO2 crystal without the reverse flow of the melt. This as-grown crystal reaches a larger dimension of 10 mm × 15 mm × 18mm. XRD analysis confirms that as-grown crystal is isostructural with TiO2 rutile phase. Moreover, this crystal has ferromagnetism at room temperature and the magnetic moment of Co ion is 1.25 × 10-2 μB/Co . After annealed at 1273 K, Co:TiO2 crystal enhances obviously its optical transmittance, while this crystal shows diamagnetism due to the disappearance of the ferromagnetic signal.

scholarly journals Influence of mechanical activation and heat treatment on magnetic properties of nanostructured mixture Ni85.8Fe10.6Cu2.2W1.4

2019 ◽  
Vol 55 (1) ◽  
pp. 85-93 ◽  
Author(s):  
M.M. Vasic ◽  
A.S. Kalezic-Glisovic ◽  
R. Milincic ◽  
Lj. Radovic ◽  
D.M. Minic ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Thermal Treatment ◽  
Mechanical Activation ◽  
Powder Mixture ◽  
Structural Characteristics ◽  
Volume Density ◽  
Magnetic Domains ◽  
Microstructural Changes ◽  
Mass Magnetization ◽  
Stress Relieving

The mechanical activation of the Ni85.8Fe10.6Cu2.2W1.4 powder mixture in the time intervals of 30-210 min in combination with thermal treatment at 393-873 K resulted in microstructural changes, forming the nanostructured mixture of the same composition but improved magnetic properties. The best result were achieved for mechanical activation during 120 min and thermal treatment at temperatures close to the Curie temperature (693K), enhancing the mass magnetization of the starting powder mixture by about 57%. The microstructural changes, which include the structural relaxation, decrease in free volume, density of dislocation and microstrain, improve structural characteristics of material, enabling better mobility of walls of magnetic domains and their better orientation in applied magnetic field and consequently enabling better mass magnetization of the material. With longer time of milling, the growing stress introduced in the sample undergoes easier relief, relocating stress-relieving processes toward lower temperatures.

Fabrication and Magnetic Properties of Mullite Based Nanocomposites with Embedded FeCr Alloy Nanoparticles

2006 ◽  
Vol 510-511 ◽  
pp. 286-289
Author(s):  
Hao Wang ◽  
Wei Min Wang ◽  
Zheng Yi Fu ◽  
Tohru Sekino ◽  
Koichi Niihara
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Alloy Nanoparticles ◽  
Fecr Alloy ◽  
Acid Washing ◽  
Property Measurement ◽  
Nanocomposite Powders

Mullite-based nanocomposites with embedded FeCr alloy nanoparticles were synthesized by reduction of sol-gel prepared Al5.4(Fe0.8Cr0.2)0.6Si2O13 solid solution in hydrogen. The feature of the formation of FeCr alloy is characterized by XRD analysis. Structural characterization revealed that the intragranular FeCr alloy nanoparticles along with inter-granular iron grains were obtained in as reduced sample. After acid washing, the intergranular metal grains were eliminated. The static magnetic properties of nanocomposite powders were studied using Magnetic Property Measurement System. It is found that part of the intra-granular metal nanoparticles have superparamagnetic behavior at room temperature.

Pigmenting agents in martian soils: Inferences from spectral, Mössbauer, and magnetic properties of nanophase and other iron oxides in Hawaiian palagonitic soil PN-9

1993 ◽  
Vol 57 (19) ◽  
pp. 4597-4609 ◽  
Author(s):  
Richard V. Morris ◽  
D.C. Golden ◽  
James F. Bell ◽  
Howard V. Lauer ◽  
John B. Adams
Keyword(s):  
Magnetic Properties ◽  
Iron Oxides

scholarly journals Influence of Hydrofluoric Acid Leaching and Roasting on Mineralogical Phase Transformation of Pyrite in Sulfidic Mine Tailings

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 513 ◽  
Author(s):  
Babak Koohestani ◽  
Ahmad Khodadadi Darban ◽  
Pozhhan Mokhtari ◽  
Esmaeel Darezereshki ◽  
Erol Yilmaz ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Phase Transformation ◽  
Iron Oxides ◽  
Mine Tailings ◽  
Hydrofluoric Acid ◽  
Surface Characterization ◽  
Acid Leaching ◽  
Roasting Process ◽  
Pyrite Content ◽  
Mineralogical Phase

Under the oxidative roasting process, pyrite, as a major mineral in sulfidic mine tailings, can transform to iron oxides. Generated iron oxides, if exhibiting enough magnetic properties, can be recovered via magnetic separation resulting in partial mine tailings valorization. However, due to the presence of various minerals and sintering possibility, it is advantageous to remove impurities and increase the pyrite content of mine tailings prior to the roasting procedure. In this case, hydrofluoric acid that has no influence on pyrite can be used to leach most inorganic minerals, including aluminosilicates. Therefore, this study investigated and compared the influence of the roasting process with and without hydrofluoric acid leaching pretreatment on mineralogical phase transformation of pyrite and magnetic properties of thermally generated minerals. Several tests and analyses were performed to study mineralogical phase transformation, morphology, elemental composition, surface characterization, and magnetic properties. Results of this study indicated that without acid leaching pretreatment, pyrite was mainly transformed to hematite. However, via acid leaching, fluorine, as a more electronegative element over oxygen, entered the compound and neglected the role of oxygen in thermal oxidation, instead reducing sulfur content of pyrite to only form pyrrhotite.

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.

Magnetic Properties of Irradiated Nickel Ferrite Thermoplastic Natural Rubber Nanocomposite

2014 ◽  
Vol 879 ◽  
pp. 206-212 ◽  
Author(s):  
Sivanesan Appadu ◽  
Sahrim Hj. Ahmad ◽  
Chantara Thevy Ratnam ◽  
Meor Yahaya Razali ◽  
Moayad Husein Flaifel ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Thermal Properties ◽  
Natural Rubber ◽  
Weight Ratio ◽  
Xrd Analysis ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Magnetic Microstructure ◽  
Sem Image ◽  
Thermoplastic Natural Rubber

The effect of electron beam (EB) irradiation at different doses on the magnetic, microstructure, morphological and thermal properties of NiFe2O4/Thermoplastic Natural Rubber (TPNR) nanocomposite was investigated. The NiFe2O4/TPNR nanocomposite samples were prepared by using a Haake mixer in weight ratio of 12:88. The TPNR matrix consists of natural rubber (NR), liquid natural rubber (LNR) and high density polyethylene (HDPE) in weight ratio of 20:10:70. The samples were irradiated using a 2 MeV EB machine in doses from 0 - 200 kGy. Magnetic properties studied by using the vibrating sample magnetometer (VSM) at room temperature showed that the values of saturation magnetization (MS), remanence magnetization (MR) and the coercivity (HC) value increased with increasing doses of irradiation. The increase in MSand MRvalues is attributed to the increase in concentration of Fe3+ions at octahedral B-site and decrease of concentration at the tetrahedral A-site in the NiFe2O4cubic structure. X-ray diffraction (XRD) analysis of the samples showed that peak intensities decreased and the width of the peaks increased with increasing doses of irradiation. Scanning electron microscope (SEM) image of the nanocomposite cross section showed the presence of defects which is more visible with increasing doses of irradiation. In the case of thermal properties, differential scanning calorimetry (DSC) analysis showed that the crystallization temperature (Tc) and the degree of crystallinity (Xc) of the nanocomposite samples decreased with increasing doses of irradiation due to crosslinking of polymeric chains which hinders the growth of crystals.

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