Effect of Milling in Various Media and Annealing on the Structure and Magnetic Properties of Strontium Hexaferrite Powder

2012 ◽  
Vol 190 ◽  
pp. 183-187 ◽  
Author(s):  
S.V. Ketov ◽  
E.A. Lopatina ◽  
T.A. Bulatov ◽  
Yu.D. Yagodkin ◽  
V.P. Menushenkov
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Oleic Acid ◽  
Milling Time ◽  
Strontium Hexaferrite ◽  
Powder Particle Size ◽  
Nanocrystalline State ◽  
Abrupt Decrease ◽  
Phase Type ◽  
Crystallite Sizes

In the present work, the structure and magnetic properties of strontium hexaferrite powder during milling in various media and subsequent annealing were studied. The milling of the powder leads to an abrupt decrease in the powder particle size and the average crystallite sizes as well as an increase in lattice microstrains of the SrFe12O19 phase. During milling in toluene, no changes in the phase composition were observed, whereas, during milling in water, the Fe2O3 phase (type H1.1) is formed. In the powder milled in oleic-acid-containing toluene a small quantity of α-Fe was found. After milling, the saturation magnetization and remanence decrease; at the same time, the coercive force of the powder milled in toluene is unchanged with increasing milling time, but slightly increases after milling in water and in oleic-acid-containing toluene. The annealing allowed us to increase the magnetic properties of the powder. It is conditioned by formation of nanocrystalline state. Moreover, the magnetic properties values depend on the medium and time of milling. The annealed powders are characterized by the following magnetic properties: μ0Нci = 0.42 ÷ 0.49 T, Br = 0.23 ÷ 0.24 T, (BH)max = 8-9.6 kJ/m3.

scholarly journals LOW-TEMPERATURE SYNTHESIS OF SUPERPARAMAGNETIC Zn0.8Ni0.2Fe2O4 FERRITE NANOPARTICLES

2018 ◽  
Vol 56 (1) ◽  
pp. 31
Author(s):  
Luong Thi Quynh Anh ◽  
Nguyen Van Dan ◽  
Do Minh Nghiep
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Oleic Acid ◽  
Low Temperature ◽  
Coercive Force ◽  
Saturation Magnetization ◽  
Ferrite Nanoparticles ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Co Precipitation

The crystalline nanoparticles of Ni0.2Zn0.8Fe2O4 ferrite were synthesized by chemical co-precipitation with precursor concentration of 0.1M, then modified by 0.25M solution of oleic acid in pentanol, finally heated at temperatures 120, 140, 160 and 180oC for 6h in autoclave. The XRD, EDS and TEM confirmed that all of samples are crystalline and their particle size are 6, 6.5, 7 and 8 nm. The magnetic properties showed that the coercive force, the remanence of samples are about zero, the saturation magnetization Ms has values from 14.20 to 27.12 emu/g.

scholarly journals Pengaruh waktu milling terhadap Sifat mikro struktur dan magnet dari NdFeB dengan proses Wet dan Dry milling

2021 ◽  
Vol 9 (1) ◽  
pp. 9-16
Author(s):  
Wahyu Solafide Sipahutar ◽  
◽  
William William ◽  
Muljadi Muljadi ◽  
◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Magnetic Flux ◽  
Time Variation ◽  
Annealing Temperature ◽  
Milling Time ◽  
Dry Milling ◽  
Wet Milling ◽  
Milling Method

Making of magnets from NdFeB flakes by Wet and dry milling to determine the microstructure, physical and magnetic properties of the milling time variation is 16, 24, and 48 hours. The milling powder is then analysed to determine the particle size with PSA and XRD to determine the phase formed. Then the compacting process with isotropy printing for making pellet test samples with a pressure of 7 tons for 2 minutes. Then the pellet sample, given annealing temperature with a variation of 150 and 170 ̊C, then a measurement of magnetic properties with a Gauss Meter. The results obtained by the smallest optimum particle size with 48 hours of milling time at a diameter of 90% 4.7 μm, while the results of dry milling at a diameter of 90% amounted to 60.85 μm. The best method to get the smallest particle size is the Wet milling method. XRD results with Wet and Dry milling phases that appear only Nd2Fe14B phase. As milling time increases, the resulting density increases. The largest magnetic flux testing with dry milling method with 48 hours of milling time for temperatures 170 ̊C temperature obtained 468.5 Gauss and the addition of annealing temperature the magnetic properties of the material is getting better.

The Effect of Milling Time on Physical Properties, Magnetic Properties and Microstructure of Bonded Magnet BaFe12O19

2020 ◽  
Vol 855 ◽  
pp. 34-39
Author(s):  
Suprapedi ◽  
Muljadi ◽  
Priyo Sardjono ◽  
Ramlan Ramlan
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Particle Size Distribution ◽  
Physical Properties ◽  
Bulk Density ◽  
Ball Mill ◽  
Milling Time ◽  
Mixed Powder ◽  
Bonded Magnet

A bonded permanent magnet of Barium hexa Ferrite has been made using powder BaFe12O19 (commercial ferrite) and a polymer of bakelite powder as binder. The composition of bakelite was varried 5% wt. The preparation of sample was begun with mass weighing for each material, then mixed together using ball mill for 1, 6 and 12 hours and using aquades as milling media. The mixed powder is dried in an oven at 110 °C for 4 hours, then the particle size distribution was measured. After that, the dried sample powder was pressed to form a pellet at pressure 40 MPa and temperature about 160 °C for 20 minutes. The characterization of sample pellet was done such as measurement of bulk density, hardness , magnetic properties using VSM and anylisis of microstructure using SEM. The results of the characterization show that the density and magnetic properties tend to increase with increasing of milling time, where the highest density, hardness and highest magnetic properties are achieved at sample with milling time for 12 hours. The value of magnetic properties at this condition are flux magnetic of 530 Gauss, remenance of 3100 Gauss, coercivity of 1,10 kOe.

Effect of Powder Particle Size and Substrate Hardening on the Formation of Nanostructured TiC Coating on AISI-D2 Steel by Mechanical Milling

2013 ◽  
Vol 829 ◽  
pp. 471-475
Author(s):  
Farhad Saba ◽  
Shahram Raygan ◽  
Hossein Abdizadeh
Keyword(s):  
Particle Size ◽  
Powder Particle ◽  
Mechanical Milling ◽  
Milling Time ◽  
Structural Characteristics ◽  
High Energy ◽  
Powder Particle Size ◽  
Aisi D2 Steel ◽  
Aisi D2 ◽  
D2 Steel

In this study TiC coating was formed on AISI-D2 steel by mechanical milling. In this regard, steel sample, balls and the powder were placed within a milling vial. Ball milling were carried out with annealed and quench-tempered samples using TiC powder having particle sizes of 44 and 200 μm for 5, 10, 15, 20, 50 and 100 h. During milling treatment, sample surface was exposed to high energy collisions and powder particles trapped between balls and sample adhered to the surface through cold welding. It was shown that the thickness and the structure of the coating depended on powder particle size; hardness and milling time. The thickness of the coating increased at first and decreased thereafter with milling time. The results showed that the substrate hardening decreased the thickness of the coating. Scanning Electron Microscopy (SEM) was employed to investigate the structural characteristics of the coatings. X-ray Diffraction (XRD) analysis was also conducted to determine the kind of phases in the coating. SEM investigations showed that the greatest thickness of the coating was reached after 20 h of milling. Furthermore, no new phases were detected in the XRD results after 100 h. It was shown that the thickness and hardness of coatings with coarse particle size were lower than that of the other. It was revealed that lattice parameter of TiC coating increased with milling time.

The Influence of Powder Particle Size on Behavior of Hot Plastic Deformation, Structure and Magnetic Properties of Nd-Fe-B Die-Upset Magnets

2012 ◽  
Vol 190 ◽  
pp. 196-199 ◽  
Author(s):  
Wojciech Lipiec
Keyword(s):  
Plastic Deformation ◽  
Particle Size ◽  
Magnetic Properties ◽  
Powder Particle ◽  
Deformation Process ◽  
Powder Particle Size ◽  
Deformation Structure ◽  
Plastic Properties ◽  
Hot Plastic Deformation ◽  
Plastic Deformation Process

The influence of powder particle size on behaviour of hot plastic deformation, structure and magnetic properties of Nd–Fe–B die-upset magnets have been examined. It was found, that powder particle size strongly affected plastic properties of material during hot deformation process. Precursors made of powder with the smallest particles (d < 32 μm) shown bigger plastic resistance than those made of powder with the larger ones (32 – 88 or 88 – 350 μm). For the same pressing force and temperature, applied within hot plastic deformation process, precursors made of the smallest particle powder allowed to obtain only 56 % deformation, while the another, made of larger particle powder: 65% deformation.

Investigation of Particle Size Effects on the Magnetic Properties and Corrosion Behaviour of Mechanically Alloyed Nd-Fe-B Powder

2006 ◽  
Vol 306-308 ◽  
pp. 971-976
Author(s):  
H.K. Jun ◽  
Iskandar Idris Yaacob
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Milling Time ◽  
Corrosion Behaviour ◽  
Amorphous State ◽  
Surface Damage ◽  
Mass Gain ◽  
Mechanically Alloyed ◽  
Xrd Pattern ◽  
Lower Particle Size

Elemental powders of Nd, Fe and B were mechanically alloyed using a planetary ball mill. The change of structure and particle size was examined. XRD pattern revealed that with prolong milling, the mixture of the powders was transformed to nearly amorphous state. Smaller particle size was observed with prolong milling. Magnetization of the mixture of powders was studied using AGM. The saturation magnetization of the mixture was observed to increase initially and then decrease with increasing milling time. The reduction of the magnetic properties was suspected to be due to surface damage which was incurred by extensive milling. The corrosion rate was observed to be higher for larger particle size (low milling time). This indicated higher mass gain percentage of larger particle size compared to lower particle size. The magnetic properties however, did not should any significant improvement after corrosion effect.

Structural Evolution in the Processing of Fe/ BaFe12O19 Nano Composite via Mechanical Alloying

2008 ◽  
Vol 55-57 ◽  
pp. 569-572
Author(s):  
Abolghasem Ataie ◽  
R. Nikkhah-Moshaie
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Milling Time ◽  
Magnetic Phase ◽  
Sol Gel ◽  
Barium Hexaferrite ◽  
Combustion Method ◽  
Magnetic Composite ◽  
Phase Constitution ◽  
Mean Particle Size

Barium hexaferrite particles derived from sol-gel combustion method with a mean particle size of 160 nm and Fe particles with a mean particle size of 150 µm were mechanically alloyed using planetary ball mill. Phase constitution and EDS analysis of the products were investigated by XRD and SEM, respectively. Magnetic properties of samples were measured by VSM. Influence of the milling time and Fe content on the phase constitution of synthesized composites has been investigated. XRD results indicated that in sample with 90 and 50wt% Fe, the magnetic composite with enhanced magnetic properties, formed based on Fe phase while barium hexaferrite particles embedded within Fe particles. In sample with 90% Fe, the crystallite size of Fe reduced from 173 to 87 nm by increasing the milling time from 1 to 20 h; saturation magnetization of the 20 h milled sample was measured as 94.8 emu/g. Besides, in sample with 50wt% Fe, some FeO phase was detected which is probably due to the partial decomposition of hard magnetic phase during milling. Sample with 10wt% Fe showed completely different behavior and magnetite appeared as a major magnetic phase.

The Effect of Powder Particle Size on the Structural and Magnetic Properties of Bonded NdFeB Magnet

2015 ◽  
Vol 1123 ◽  
pp. 88-91 ◽  
Author(s):  
Didik Aryanto ◽  
Zailani Ray ◽  
Toto Sudiro ◽  
Agus Sukarto Wismogroho ◽  
Nanang Sudrajat
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Powder Particle Size ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Ndfeb Magnet ◽  
Particle Size Range ◽  
X Ray ◽  
Diffraction Peaks ◽  
Powder Type

Commercially, NdFeB powder (type MQP-B+) with difference in particle sizes were used in this study. The powders were isotropically compressed and heat cured at 150°C for 30 minute. The samples were then magnetized and characterized by impulse magnetizer K series and permagraph MAGNET-PHYSIK Dr. Steingroever GmbH, respectively. According to the results of SEM characterization, compacted powder showed a homogeneous plate distribution. The surface morphology also indicated the presence of pores in the bonded NdFeB magnet. X-ray diffraction analysis from all samples revealed that the diffraction peaks were detected as tetragonal Nd2Fe14B-phase. There was no significant different in magnetic properties of bonded magnets with different in particle size. The optimum Br, Hcb, and (BH)max were achieved at particle size range of 150-297 mm.

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