Physical and Magnetic Characterization of Hard/Soft SrFe12O19/CoFe2O4 Nanocomposite Magnets Made by Mechanical Alloying and Ultrasonic Irradiation

2021 ◽  
Vol 69 ◽  
pp. 53-66
Author(s):  
Novrita Idayanti ◽  
Dedi ◽  
Azwar Manaf
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Magnetic Properties ◽  
Mechanical Alloying ◽  
Ultrasonic Irradiation ◽  
Crystal Size ◽  
Morphological Characteristics ◽  
Porosity Reduction ◽  
Nanocomposite Magnets ◽  
Ultrasonic Time

In this study, the particle sizes of SrFe12O19 in hard/soft SrFe12O19/CoFe2O4 nanocomposite magnets made using mechanical alloying and ultrasonic irradiation were investigated. SrFe12O19/CoFe2O4 nanocomposites were combined in a ratio of 75:25, with each magnetic material being prepared separately. SrFe12O19 powder was prepared from Fe2O3 and SrCO3 powder by mechanical alloying and ultrasonic irradiation for different times, 0, 3, 6, 9, and 12 h. Varying the ultrasonic time during the preparation of the SrFe12O19 samples resulted in differences in morphological characteristics, crystal structure, particle size, crystal size, microstrain, density, porosity, and magnetic properties. The longer the ultrasonic time, the crystal size and particle size decreases, the density increases, and the porosity reduction which affects the magnetic properties. SrFe12O19 after 12 h ultrasonic process reach Ms value = 61.29 emu/g. CoFe2O4 powder was produced from Fe2O3 and CoCO3 powder by mechanical alloying with a 10 h milling time. Furthermore, each SrFe12O19 sample was composited with CoFe2O4 powder by ultrasonic irradiation for 1 h and these composite samples also showed different characteristics, where there is an increase in Mr and Ms compared to the single SrFe12O19. The morphology, crystal structure, particle size, and magnetic properties of the samples were measured using scanning electron microscopy, X-ray diffraction, particle size analysis, and PERMAGRAPH. The crystal size and microstrain were calculated using a Williamson–Hall plot, and density and porosity were determined using Archimedes’ law.

Fabrication of Nanostructured Fe-Co Alloy Powders by Hydrogen Reduction and Its Magnetic Properties

2007 ◽  
Vol 534-536 ◽  
pp. 1389-1392
Author(s):  
Young Jung Lee ◽  
Baek Hee Lee ◽  
Gil Su Kim ◽  
Kyu Hwan Lee ◽  
Young Do Kim
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Grain Size ◽  
Magnetic Properties ◽  
Nanostructured Materials ◽  
Hydrogen Reduction ◽  
Internal Strain ◽  
Oxide Powder ◽  
Powder Mixtures ◽  
Effect Of Microstructure

Magnetic properties of nanostructured materials are affected by the microstructures such as grain size (or particle size), internal strain and crystal structure. Thus, it is necessary to study the synthesis of nanostructured materials to make significant improvements in their magnetic properties. In this study, nanostructured Fe-20at.%Co and Fe-50at.%Co alloy powders were prepared by hydrogen reduction from the two oxide powder mixtures, Fe2O3 and Co3O4. Furthermore, the effect of microstructure on the magnetic properties of hydrogen reduced Fe-Co alloy powders was examined using XRD, SEM, TEM, and VSM.

The Mechanical Alloying of Magnetite Concentrate with Biochar

2020 ◽  
Vol 10 (2) ◽  
pp. 116-125
Author(s):  
Elif Aranci Öztürk ◽  
Mustafa Boyrazli ◽  
Mehmet Deniz Turan ◽  
Murat Erdemoğlu
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Grain Size ◽  
Mechanical Alloying ◽  
Milled Powder ◽  
Spherical Particles ◽  
Size Analysis ◽  
Biomass Waste ◽  
Magnetic Separator ◽  
Magnetite Concentrate

Aim: In this work, the effect of milling time on the mechanical alloying of the mixture containing the magnetite concentrate and biomass waste was investigated. Materials and Methods: The ore’s grade consisting of hematite and magnetite minerals was increased from 49.87% Fe to 67.29% Fe using the low intensity wet magnetic separator. Biomass waste which was supplied from ÇAYKUR black tea facilities, used as a carbon source was subjected to carbonization processes at 800°C for 1440 min. After the carbonization process, the carbon and sulphur contents of the biomass were measured as 94.68% and 0.03%, respectively. For the mechanical alloying process, a mixture consisting of magnetite concentrate with a grain size of -45 μm and biomass which was added two times the amount of carbon required for the reduction of magnetite to metallic iron was used. Result: After the mechanical alloying process which was carried out at different times, it was observed in the particle size analysis that the particle size of 90% of the mixture was reduced to about 4 μm. In SEM (Scanning Electron Microscopy) images, cube-like particles along with the spherical particles were observed depending on the mechanical alloying times. After 45 minutes of alloying, it was observed that the carbonized product milled together with magnetite concentrate was partially integrated into the crystal structure. Conclusion: The carbonized tea plant waste milled together with magnetite concentrate was partially integrated into the crystal structure. And the mechanical alloying provide to increase in the specific surface area in parallel with the grain size decrease in the study. Thus, in the later stage of the study, the milled powder acquired more ability to react.

Crystal structure, microstructure, and magnetic properties of the Fe2CrSi nanostructured Heusler alloy elaborated by the mechanical alloying method

2020 ◽  
Vol 111 (8) ◽  
pp. 681-687
Author(s):  
Fatiha Djaidi ◽  
Hanane Mechri ◽  
Mohammed Azzaz
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Magnetic Properties ◽  
Mechanical Alloying ◽  
Heusler Alloy ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Disordered Crystal ◽  
Microstructure And Magnetic Properties

Abstract The Fe2CrSi nanostructured Heusler alloy was prepared by mechanical alloying followed by heat treatment. The structure, microstructure, and magnetic properties of the samples were studied by the following analysis methods: X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectrometry, transmission electron microscopy, and a vibrating sample magnetometer. The a-Fe (Si, Cr) solid solution with a disordered body centered cubic (bcc) crystal structure was obtained after 24 h of milling. An example of the sample milled for 32 h with a disordered crystal structure a-Fe(Si, Cr) was chosen to investigate the transformation with temperature using differential scanning calorimetry. The effect of annealing temperatures on the structural, microstructural, and magnetic properties of the ordered Fe2CrSi Heusler phase for the sample milled for 32 h was investigated.

Effects of preparation processes on structure and magnetic properties of Nd2Fe14B/α–Fe-type nanocomposite magnets

2001 ◽  
Vol 16 (3) ◽  
pp. 709-715 ◽  
Author(s):  
Bao-zhi Cui ◽  
X. K. Sun ◽  
L. Y. Xiong ◽  
Wei Liu ◽  
Zhi-dong Zhang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Mechanical Alloying ◽  
Mechanical Milling ◽  
Magnetic Energy ◽  
Homogeneous Distribution ◽  
Grain Sizes ◽  
Energy Product ◽  
Nanocomposite Magnets ◽  
Intrinsic Coercivity

The structure and magnetic properties of Nd8.4Fe86Mo1.1B4.5 nanostructured magnets prepared by mechanical alloying (MA), compared with those by mechanical milling (MM), were studied. The intrinsic coercivity μ0Hc, the reduced remanence Jr/Js, and the maximum magnetic energy product (BH)max for Nd8.4Fe86Mo1.1B4.5 magnets were prepared by MM were notably higher than the values of the corresponding MA-prepared samples. The average grain sizes of both α–Fe and Nd2Fe14B in the MM-prepared samples were measurably smaller than corresponding values of the MA-prepared samples. A more homogeneous distribution of α–Fe grains in the MM-prepared samples than in the MA-prepared samples was obtained.

Structurization and Properties of Magnetoplastics Made of Mechanically Activated Amorphous-Crystalline Powder Alloys Based on the Nd-Fe-B System

2018 ◽  
Vol 284 ◽  
pp. 455-459
Author(s):  
V.G. Perederiy ◽  
B.G. Gasanov ◽  
A.A. Aganov
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Magnetic Properties ◽  
Melt Spinning ◽  
Crystalline Powder ◽  
Sintered Magnets ◽  
Powder Alloys ◽  
Kinetics Of Formation ◽  
Kinetics Of

The influence of the method of melt spinning on the basis of the Fe-Nd-B system on the amorphous-crystal structure of ribbons and flakes is shown. It is established that the magnetic properties of magnetoplasts depend on the powders particle size, the parameters of mechanic activation during flake milling, the kinetics of formation and growth of Fe2Nd14B phase nuclei at all stages of their preparation and processing, etc. Isotropic and anisotropic magnetoplasts and sintered magnets with magnetic properties: Br = 0.5-1.25 T, HcB = 180-700 kA/m; (BH)max = 50-280 kJ/m3.

scholarly journals The Effect of Electrode Topography on the Magnetic Properties and MRI Application of Electrochemically-Deposited, Synthesized, Cobalt-Substituted Hydroxyapatite

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 200 ◽  
Author(s):  
Wei-Chun Lin ◽  
Chun-Chao Chuang ◽  
Chen-Jung Chang ◽  
Ya-Hsu Chiu ◽  
Cheng-Ming Tang
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Titanium Dioxide ◽  
Magnetic Nanoparticles ◽  
Cobalt Oxide ◽  
Crystal Size ◽  
Image Contrast ◽  
Potential Candidate ◽  
Hydroxyapatite Nanoparticles ◽  
Mri Image

Magnetic nanoparticles are used to enhance the image contrast of magnetic resonance imaging (MRI). However, the development of magnetic nanoparticles with a low dose/high image contrast and non-toxicity is currently a major challenge. In this study, cobalt-substituted hydroxyapatite nanoparticles deposited on titanium (Ti-CoHA) and cobalt-substituted hydroxyapatite nanoparticles deposited on titanium dioxide nanotubes (TNT-CoHA) were synthesized by the electrochemical deposition method. The particle sizes of Ti-CoHA and TNT-CoHA were 418.6 nm and 127.5 nm, respectively, as observed using FE-SEM. It was shown that CoHA can be obtained with a smaller particle size using a titanium dioxide nanotube (TNT) electrode plate. However, the particle size of TNT-CoHA is smaller than that of Ti-CoHA. The crystal size of the internal cobalt oxide of CoHA was calculated by using an XRD pattern. The results indicate that the crystal size of cobalt oxide in TNT-CoHA is larger than that of the cobalt oxide in Ti-CoHA. The larger crystal size of the cobalt oxide in TNT-CoHA makes the saturation magnetization (Ms) of TNT-CoHA 12.6 times higher than that of Ti-CoHA. The contrast in MRIs is related to the magnetic properties of the particles. Therefore, TNT-CoHA has good image contrast at low concentrations in T2 images. The relaxivity coefficient of the CoHA was higher for TNT-CoHA (340.3 mM−1s−1) than Ti-CoHA (211.7 mM−1s−1), and both were higher than the commercial iron nanoparticles (103.0 mM−1s−1). We showed that the TNT substrate caused an increase in the size of the cobalt oxide crystal of TNT-CoHA, thus effectively improving the magnetic field strength and MRI image recognition. It was also shown that the relaxivity coefficient rose with the Ms. Evaluation of biocompatibility of CoHA using human osteosarcoma cells (MG63) indicated no toxic effects. On the other hand, CoHA had an excellent antibacterial effect, as shown by E. coli evaluation, and the effect of TNT-CoHA powder was higher than that of Ti-CoHA powder. In summary, TNT-CoHA deposited electrochemically on the TNT substrates can be considered as a potential candidate for the application as an MRI contrast agent. This paper is a comparative study of how different electrode plates affect the magnetic and MRI image contrast of cobalt-substituted hydroxyapatite (CoHA) nanomaterials.

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