Microstructure and Magnetic Properties of Fe-6.5wt%Si Alloy Obtained by Spray Forming Process

2005 ◽  
Vol 498-499 ◽  
pp. 111-118 ◽  
Author(s):  
Mário Cézar Alves da Silva ◽  
Claudemiro Bolfarini ◽  
Claudio Shyinti Kiminami
Keyword(s):  
Magnetic Properties ◽  
Coercive Force ◽  
Power Loss ◽  
Antiphase Domain ◽  
Spray Forming ◽  
Forming Process ◽  
Annealing Temperatures ◽  
Average Grain Size ◽  
Maximum Permeability ◽  
Microstructure And Magnetic Properties

Deposits of the Fe-6.5wt%Si alloy produced by spray forming were annealed at temperatures between 900 and 1300oC, during 1h in vacuum and quenched in oil at temperatures between 300 and 700oC, separately. Magnetic properties, singular microstructure and random crystallographic texture were measured. After annealing at 1250°C for 1h under vacuum, the average grain size is of 500 μm, the grain orientation is random and the magnetic properties were: power loss of 1.30 W/kg, maximum permeability of 15400 and coercive force of 40 A/m, at B=1 T, f=60 Hz by using 0.60 mm thick rings for all studied samples. Higher annealing temperatures cause no decreasing of these properties. After quenched at 700°C, an improvement the magnetic properties where detected due to antiphase domain B2 growth. The magnetic properties were: power loss of 1.59 W/kg, maximum permeability of 12300 and coercive force of 76 A/m, at B=1 T, f=60 Hz.

Effects of Order-Disorder Reactions on the Magnetic Properties of Rapidly Quenched Fe-6.5% Si Alloy

2014 ◽  
Vol 802 ◽  
pp. 530-534
Author(s):  
F.A. Nascimento ◽  
M.C.A. da Silva
Keyword(s):  
Magnetic Properties ◽  
Coercive Force ◽  
Domain Structure ◽  
Power Loss ◽  
Magnetic Measurement ◽  
Annealing Treatment ◽  
Antiphase Domain ◽  
Spray Forming ◽  
Soft Magnetic ◽  
Treatment Conditions

Deposits of the Fe-6.5wt%Si alloy rapidly quenched by spray forming were investigated. The order phase can be either B2 or DO3 depending on annealing treatment conditions. The observation of pairs dislocations indicates the presence of super dislocations and B2 antiphase boundaries (APBs) which affects significantly the soft magnetic properties. The dislocations bound the APBS which yield δ fringes when image 200 superlattice reflections. Samples treated at 700oC for 1 h were oil quenched, this has induced a decreasing of power loss and the TEM micrographs have showed developed 1⁄4 <111> antiphase domain structure in the B2 phase. The magnetic properties were: power loss of 1.59 W/kg and coercive force of 76 A/m, at B=1 T, f=60 Hz. The samples annealed at 1250°C for 1h showed the same interaction between the APBs but better power losses on their magnetic properties. The magnetic properties were: 1.30 W/kg power loss and 40 A/m coercive force, at same conditions described above. This suggests a strong interaction between magnetic properties and antiphase domain structure in the B2 ordered phase. Optical microscopy observations corroborate the magnetic measurement conclusions.

scholarly journals Impact of ZrO2 Additive on Microstructure, Magnetic Properties, and Temperature Dependence of the Initial Permeability of LiTiZn Ferrite Ceramics

2021 ◽  
Author(s):  
Andrey Malyshev ◽  
Anna B. Petrova ◽  
Anatoly P. Surzhikov
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
Defect Structure ◽  
Initial Permeability ◽  
Experimental Temperature ◽  
Mathematical Treatment ◽  
Experimental Temperature Dependence ◽  
Average Grain Size ◽  
Soft Ferrite ◽  
Microstructure And Magnetic Properties

Abstract The effect of the diamagnetic ZrO2 addition on the microstructure and magnetic properties of LiTiZn ferrite ceramics, including the shape and parameters of the temperature dependence of the initial permeability, has been investigated. The defect structure of ferrite ceramic samples is assessed according to our earlier proposed method based on mathematical treatment of the experimental temperature dependencies of the initial permeability. The method is recommended for defects monitoring of soft ferrite ceramics and ferrite products. It was found that the defect structure of ferrite ceramics increased by 350% with an increase in the concentration of the ZrO2 additive in the range of (0–0.5) wt.%. In this case, for the same samples, the increase in the true physical broadening of reflections is only 20%, and the coercive force by 50%. Simultaneously, the maximum of the experimental temperature dependence of the initial permeability dropped by 45%. The microstructure of all samples is characterized with a similar average grain size according to the SEM data. However, samples with the 0.5wt.% of ZrO2 are characterized by the formation of conglomerates. A linear relationship was obtained between the defect structure and the width of the reflections, which indicates that this parameter is related to the elastic stress of ferrite ceramics.

MICROSTRUCTURE AND MAGNETIC PROPERTIES OF NANOSTRUCTURED Al2O3-20vol%Fe70Co30 COMPOSITE PREPARED BY HIGH ENERGY MECHANICAL MILLING

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1383-1388 ◽  
Author(s):  
MASLEEYATI YUSOP ◽  
DELIANG ZHANG ◽  
MARCUS WILSON ◽  
NICK STRICKLAND
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Alloy Powder ◽  
Milling Time ◽  
High Energy ◽  
Composite Powders ◽  
Nanostructured Composite ◽  
Alloy Particles ◽  
Average Grain Size ◽  
Microstructure And Magnetic Properties

Al 2 O 3-20 vol % Fe 70 Co 30 composite powders have been prepared by high energy ball milling a mixture of Al 2 O 3 powder and Fe 70 Co 30 alloy powder. The Fe 70 Co 30 alloy powder was also prepared by mechanical alloying of Fe and Co powders using the same process. The effects of milling duration from 8 to 48 hours on microstructure and magnetic properties of the nanostructured composite powders have been studied by means of X-ray Diffractometry (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). It was found that the nanostructured composite powder particles with irregular shapes and Fe 70 Co 30 alloy particles being embedded in them formed after 8 hours of milling. The average grain size of the Al 2 O 3 matrix reduced drastically to less than 18nm after 16 hours of milling. On the other hand, the embedded alloy particles demonstrated almost unchanged average grain size in the range of 14-15nm. Magnetic properties of the powder compacts at room temperature were measured from hysteresis curves, and show strong dependence of the milling time, with the coercivity increasing from 67.1 up to 127.9kOe with increasing the milling time from 8 to 48 hours. The possible microstructural reasons for this dependence are discussed.

EFFECT OF COPPER OXIDE ON THE GRAIN GROWTH AND INITIAL PERMEABILITY OF Mg–Cu–Zn FERRITES

2010 ◽  
Vol 24 (02) ◽  
pp. 169-182
Author(s):  
M. MANJURUL HAQUE ◽  
M. HUQ ◽  
SYED FARID UDDIN FARHAD ◽  
JASIM UDDIN KHAN ◽  
M. A. HAKIM
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Grain Growth ◽  
Spinel Phase ◽  
Initial Permeability ◽  
Cu Content ◽  
Average Grain Size ◽  
Zn Ferrite ◽  
Effect Of Copper ◽  
Microstructure And Magnetic Properties

The microstructure and magnetic properties of Mg – Cu – Zn ferrites prepared by using solid-state reaction method have been investigated. X-ray diffraction (XRD), a scanning electron microscope (SEM), impedance analyzer and a vibrating sample magnetometer (VSM) were utilized in order to study the effect of copper substitution and its impact on the crystal structure, grain size, microstructure and magnetic properties of the Mg – Cu – Zn ferrite. The formation of cubic spinel phase was identified using XRD technique. The microstructures of the samples show that the grain growth is greatly enhanced by the addition of CuO which is attributed to the liquid phase during sintering. The average grain size (Dm) increases significantly with increasing Cu content. The initial permeability (μ') of the samples increases appreciably with increasing Cu content which is attributed to the increase of grain size and density of the samples. The resonance frequency (fr) of the samples shifts toward the lower frequency as the Cu content increases. The sharp fall of μ' in μ'-T curves is observed for all the samples which indicate the homogeneity of the samples. The saturation magnetization (Ms) of the Mg – Cu – Zn ferrites increases slightly with increasing Cu concentration.

Study of the Effect of Hot Gas on Atomization Quality of Spray Forming

2013 ◽  
Vol 774-776 ◽  
pp. 1190-1193
Author(s):  
Qing Yang ◽  
Ying Dong Qu ◽  
Rui Ming Su ◽  
Bing Kun Zheng ◽  
Yu Sheng Wu
Keyword(s):  
Mathematical Model ◽  
Grain Size ◽  
Grain Shape ◽  
Spray Forming ◽  
Forming Process ◽  
Hot Gas ◽  
Average Grain Size ◽  
Calculation Results ◽  
First Time

In the spray forming process, the atomizing quality is not very good under the low pressure. This article attempts to improve the quality of atomization through heating the gas. A mathematical model is built and calculated according to the existing knowledge, and then the influence of airflow temperature in the spray forming is theoretical calculated and analyzed. The experimental results show that the average grain size is 54μm when the gas is not heated; the average grain size is 39 μm which decreases by 27.7% than airflow unheated when the gas is heated to 150 °C. The calculation results show that when the gas is not heated, the first time atomization grain size is 201 μm, the second time atomization grain size is 15 μm, the total atomization time is 92 μs. And the velocity of atomization droplets is 80 m/s; when the airflow temperature is 150°C, the above results are 131 μm, 10 μm, 76 μs and 127 m/s respectively, the atomization quality has a certain improvement compared to the unheated condition. At the same time, the grain shape becomes more round as the temperature of airflow increases, and the holes between the grains also become smaller.

Effect of Secondary Decomposition on Coercivity of Fe-Co-Cr Alloys with 15% Co

2015 ◽  
Vol 233-234 ◽  
pp. 623-628 ◽  
Author(s):  
Vladimir P. Menushenkov ◽  
Vladimir S. Shubakov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Coercive Force ◽  
Volume Fraction ◽  
Magnetic Measurements ◽  
Magnetic Treatment ◽  
Magnetic Insulation ◽  
Transmission Electron ◽  
Microstructure And Magnetic Properties

The microstructure and magnetic properties of Fe-Co-Cr alloys with 15 wt % Co were investigated using transmission electron microscopy and magnetic measurements. The secondary decomposition within both the α2-phase matrix and the α1-phase particles was observed for magnets subjected thermo-magnetic treatment and subsequent stepped aging or continuous-cooling treatments. During high-temperature treatments (630-600оC), when the α2phase is dominant (the volume fraction is more than 50%), the secondary decomposition of this phase takes place (α2→ α1'+ α2'). The deterioration of magnetic insulation of α1-phase particles results in the decrease in the coercive force of alloys. Below 600оC, when the α1phase is dominant (the volume fraction is more than 50%), the splitting of elongated α1-phase particles occurs. When the temperature of stepped-aging decreases in high steps, the secondary decomposition (α1→ α1'+ α2') leads to the splitting of initial α1-phase particles into fine slightly elongated particles and the decrease in the coercive force.

Microstructure and Magnetic Properties of Microwave Sintered Ni0.5Zn0.5Fe2O4 Ferrite

2013 ◽  
Vol 328 ◽  
pp. 705-709
Author(s):  
Yuan Dong Peng ◽  
Qing Lin Xia ◽  
Li Ya Li ◽  
Ming Lou ◽  
Jing Zhi Hu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Microwave Sintering ◽  
Initial Permeability ◽  
Soaking Time ◽  
X Ray ◽  
Intrinsic Coercivity ◽  
Conventional Sintering ◽  
Maximum Permeability ◽  
Sintering Method ◽  
Microstructure And Magnetic Properties

Ni0.5Zn0.5)Fe2O4 ferrite has been sintered via microwave irradiation. The structural, component and magnetic properties of NiZn ferrite was determined by SEM, X-ray powder diffraction (XRD) and automatic hysteresis loop magnetometer. Results showed that the material sintered by microwave energy at 1220°C for 20min had a high purity (Ni0.5Zn0.5)Fe2O4 phase. The sample obtained magnetic properties of intrinsic coercivity 222A/m, saturation magnetization 332mT, initial permeability 0.20mH/m and maximum permeability 0.58mH/m. Compared with conventional sintering method, microwave sintering of NiZn ferrite is more efficient and reducing soaking time.

scholarly journals Effects of average grain size on the magnetic properties of permalloy films

2018 ◽  
Vol 185 ◽  
pp. 01003 ◽  
Author(s):  
Nikolay Djuzhev ◽  
Aleksey Iurov ◽  
Nikita Mazurkin ◽  
Maksim Chinenkov ◽  
Aleksey Trifonov ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Coercive Force ◽  
Substrate Temperature ◽  
Temperature Effects ◽  
Deposition Temperature ◽  
High Sensitivity ◽  
Permalloy Film ◽  
Average Grain Size

In this paper the results of substrate temperature effects on average grain size in FeNi 20:80 are shown. It was found that with an increase of the substrate temperature from 270 to 390 °C, the anisotropic magnetoresistive (AMR) effect increases from 1.2 to 2.3% and the coercive force from 1.6 to 5.3 Oe. The presence of two conflicting processes: the task of increasing AMR effect to achieve high sensitivity of AMR-sensor and to decrease the coercive force to increase the precision of conversion, leads to the necessity to find the optimum deposition temperature of the permalloy film. The dependence of the AMR effect and the coercive force on the substrate temperature during deposition was obtained. This dependence shows that the substrate temperature increasing above 320 °C leads to coercive force increasing and does not lead to a substantial AMR increasing. In this regard, the substrate temperature 320 °C was determined as optimal.

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