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.

Effect of Nitridation Magnetic Properties of Nanocrystalline Fe-Co Alloy Powders

2010 ◽  
Vol 654-656 ◽  
pp. 1106-1109
Author(s):  
Ya Qiong He ◽  
Chang Hui Mao ◽  
Jian Yang
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Alloy Powder ◽  
High Energy ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron ◽  
Nitridation Temperature ◽  
Microstructure And Magnetic Properties

Nanocrystalline Fe-Co alloy powders, which were prepared by high-energy mechanical milling, were nitrided under the mixing gas of NH3/H2 in the temperature range from 380°C to 510°C. X-ray diffraction (XRD) was used to analyze the grain size and reaction during the processing. The magnetic properties of the nitrided powders were measured by Vibrating Sample Magnetometer (VSM). The results show that with the appearance of Fe4N phase after nitride treatment, and the grain-size of FeCo phase decreases with the increase of nitridation temperature between 380°C to 450°C.The saturation magnetization of nitrided alloy powder treated at 480°C is about 18% higher than that of the initial Fe-Co alloy powder, accompanied by the reduction of the coercivity. Transmission electron microscope (TEM) was used, attempting to further analyze the effect of Fe4N phase on microstructure and magnetic properties of the powder mixtures.

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.

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 Synthesis of La1-xCaxMnO3 (x = 0 and 0.2) through ultrasonic mixing and its characterisation

2018 ◽  
Vol 197 ◽  
pp. 02010
Author(s):  
Mangasi A M ◽  
Iwan Sugihartono ◽  
Teguh B P ◽  
Sitti Ahmiatri Saptari ◽  
Erfan Handoko
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Grain Size ◽  
Single Phase ◽  
Perovskite Manganite ◽  
Stoichiometric Mixture ◽  
X Ray ◽  
Structure And Morphology ◽  
Mixing Method ◽  
Scanning Electron

In order to investigate the crystal structure and morphology of perovskite manganite materials, we have been successfully synthesized LaMnO3 and La0,8Ca0,2MnO3 systems through ultrasonic mixing method. The application of these materials is the alternative cooler technology beside freon gas using with residual emission gas. Stoichiometric mixture of La2O3, MnCO3, and CaO with more than 95 % purity were be prepared by ultrasonic mixing 40 kHz 60 watts for 30 minutes to result homogen mixtures. The samples were calcinated at 800°C for 1 h and sintered at 1100°C for 3 h. The structure of the samples was examined by X-ray diffractometer (XRD) Phillips and result as single phase of perovskite manganite materials. Morphology was studied using a 5310LV Jeol scanning electron microscope (SEM) that show the same grains of perovskite manganite material. While Ca substituted for La in the sample, the grain size decreases with decreasing the volume of cell units and finally the particle size of La0.8Ca0.2MnO3 phase decreases.

Structural, Mechanical and Magnetic Properties of Mechanically Alloyed Fe40Co60 Powders

2011 ◽  
Vol 312-315 ◽  
pp. 743-747 ◽  
Author(s):  
Fadhela Otmane ◽  
S. Bergheul ◽  
M. Zergoug ◽  
M. Azzaz
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Magnetic Measurements ◽  
Lattice Parameter ◽  
Internal Strain ◽  
Morphological Aspect ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
X Ray

In this work we report on the structural, mechanical and magnetic properties of mechanically alloyed Fe40Co60 powders. Alloying formation, grain size, lattice parameter and internal strain were investigated using X-Ray Diffraction (XRD) measurements. The morphological aspect of the nanostructured powders was analysed by means of the Scanning Electron Microscopy (SEM). Compacted pastilles with circular shape have been under Vickers test of micro Hardness and magnetic measurements of Hysterisis loops. Discussed results according to milling time show that after 60 h milling the grain refinement is about 15.59 nm with internal strain of around 0.5809 %. The micro hardness increases with the decrease of the grain size and the hysterisis loop at 60 h milling is enhanced in term of decreased coercivity.

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.

STRUCTURE AND MAGNETIC PROPERTIES OF NANOCRYSTALLINE MnZn FERRITES BY A PHASE TRANSFORMATION METHOD

2008 ◽  
Vol 22 (20) ◽  
pp. 3433-3438
Author(s):  
YONGSHENG LIU ◽  
YUNBO ZHONG ◽  
JINCANG ZHANG ◽  
ZHONGMING REN ◽  
SHIXUN CAO ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Grain Size ◽  
Phase Transformation ◽  
Magnetic Measurements ◽  
Average Particle Size ◽  
Transformation Method ◽  
Average Particle ◽  
Mnzn Ferrite ◽  
Mnzn Ferrites

Nanocrystalline Mn 0.6 Zn 0.4 Fe 2 O 4 particles are synthesized by a phase transformation method. The crystal structure of these particles is that of spinel MnZn ferrite. The average particle size is about 50 nm and the grain size is about 11 nm. Magnetic measurements show that the saturation magnetization at 120 K is ~80% larger than that at 300 K, and imply that the majority of the nanoparticles are superparamagnetic from 65 to 300 K.

Simulating Sintering Process in SmCo5 Magnets

2008 ◽  
Vol 591-593 ◽  
pp. 80-85 ◽  
Author(s):  
José Adilson de Castro ◽  
Marcos Flavio de Campos
Keyword(s):  
Growth Rate ◽  
Particle Size ◽  
Grain Size ◽  
Magnetic Properties ◽  
Grain Growth ◽  
Sintering Process ◽  
Densification Rate ◽  
Size Evolution ◽  
Sintering Conditions ◽  
Crystal Particle

SmCo5 sintered magnets are produced according the following main processing: milling until single crystal particle size, compaction and sintering. It is necessary high density to maximize remanence, but small grain size to maximize coercivity. A sintering model able to incorporate both, the densification rate and the grain growth rate, is described. This makes easier to find the better sintering conditions for optimization of the magnetic properties (coercivity and remanence). The presented model represents a refinement of previous sintering models, because it takes into account the coupled effects of grain size evolution and shrinkage.

Pengaruh Pendopingan Karbon Terhadap Struktur Kristal dan Morfologi TIO2

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Frastica Deswardani ◽  
Helga Dwi Fahyuan ◽  
Rimawanto Gultom ◽  
Eif Sparzinanda
Keyword(s):  
Thin Film ◽  
Crystal Structure ◽  
Grain Size ◽  
Tio2 Thin Film ◽  
Crystal Size ◽  
Diffraction Peak ◽  
Carbon Doping ◽  
Tio2 Anatase ◽  
Spray Method ◽  
Carbon Analysis

Telah dilakukan penelitian mengenai pengaruh konsentrasi doping karbon pada lapisan tipis TiO2 yang ditumbuhkan dengan metode spray terhadap struktur kristal dan morfologi TiO2. Hasil karakterisasi SEM menunjukkan bahwa penambahan doping karbon dapat meningkatkan ukuran butir. Lapisan TiO2 doping karbon 8% diperoleh ukuran butir terbesar adalah 1.35 μm, sedangkan ukuran tekecilnya adalah 0.45 μm. Sementara itu, untuk lapisan tipis TiO2 didoping karbon 15% memiliki ukuran butir terbesar yaitu 1.76 μm dan terkecil 0.9 μm. Hasil XRD menunjukkan seluruh puncak difraksi lapisan tipis TiO2 dengan doping karbon 8% dan 15% merupakan TiO2 anatase. Ukuran kristal lapisan TiO2 didoping karbon 8% diperoleh sebesar 638,08 Å dan untuk pendopingan 15% karbon ukuran kristal lapisan tipis TiO2 adalah 638,09 Å, hal ini menunjukkan ukuran kristal kedua sampel tidak mengalami perubahan yang signifikan.   TiO2 thin film with carbon doping has been successfully grown by spray method. The research on the effect of carbon doping on crystal structure and morfology of TiO2 has been prepared by varying carbon concentration (8% and 15% carbon). Analysis of SEM showed that the addition of carbon may increase the grain size. Thin film of TiO2 doped carbon 8% has the largest grain size 1.35 μm, while the smallest grain size is 0.45 μm. Meanwhile, for thin film TiO2 doped carbon 15% has the largest grain size 1.76 μm and smallest 0.9 μm. The XRD results showed the entire diffraction peak of thin film TiO2 doped carbon 8% and 15% were TiO2 anatase. The crystal size of thin film TiO2 doped carbon 8% was obtained at 638.08 Å and for thin film TiO2 doped carbon 15% the crystalline size of TiO2 thin film was 638.09 Å, this shows that the crystal size of both samples did not change significantly.    

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