Influence of Smelting Technology on Properties of Soft Magnetic Fe-B-Si Alloys

2014 ◽  
Vol 698 ◽  
pp. 326-332
Author(s):  
Viktor Konashkov ◽  
Vladimir Tsepelev
Keyword(s):  
Critical Temperature ◽  
Elemental Composition ◽  
Amorphous Ribbon ◽  
Soft Magnetic Materials ◽  
Relaxation Processes ◽  
Solid Alloy ◽  
Soft Magnetic ◽  
Time Processing ◽  
To Receive

The quality of metal production can be different even at identical elemental composition and similar heat treatment. The thermo-time smelting regime influences on structure of a metal melt. The structure of a melt influences on process of a hardening and quality of solid alloy. The thermo-time processing of a melt is very relevant at production of nanocristaline materials. The structure of amorphous ribbon is inherited from a melt. The long-lived relaxation processes can be exist in liquid state. They can lasts units or even tens hours. The thermo-time processing allows to receive an equilibrium melt. The properties of an equilibrium melt depend only on an elemental composition and temperature. The development of thermo-time processing is possible on the basis of analysis of different structural-sensing properties of melts. The thermo-time processing is a combination of heating temperatures and temporary ranges. But more often it is possible to determine temperature at which one a melt passes to an equilibrium state practically instantly. Such temperature is named “critical temperature”. The achievement of “critical temperature” is accompanied by anomalies on relations of properties to temperature. The quality of soft magnetic materials received from melt heated up above than “critical temperature” is higher.

scholarly journals Influence of Annealing Temperature on the Crystallization Kinetics of Fe82Si8B10 Amorphous Ribbon

2020 ◽  
Vol 11 (1) ◽  
pp. 107-112
Author(s):  
A Said Sikder ◽  
SD Nath ◽  
SS Sikder
Keyword(s):  
Crystallization Kinetics ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Amorphous Ribbon ◽  
Primary Crystallization ◽  
Soft Magnetic Materials ◽  
Power Transformers ◽  
Soft Magnetic ◽  
Potential Applications ◽  
Kinetics Of

Amorphous soft magnetic materials have significant potential applications in specialist power transformers and in inductive devices. With the composition of Fe82Si8B10, 82% of the transition metals Fe and about 18% of metalloid or glass-former elements like B and Si are strongly magnetic at room temperature and offer dynamic opportunities for engineering applications. The crystallization kinetics has been studied by differential thermal analysis (DTA). The sample was annealed in a controlled way in the temperature range of 350-450°C at constant annealing time one hour. The kinetics of primary crystallization α-Fe(Si) phase and secondary crystallization Fe2B phase was studied as affected due to temperature. The sample annealed at 350oC temperature is almost unchanged which is still lower than that of primary crystallization temperature but the same condition when sample annealed at 450°C completely shows that the primary crystallization α-Fe(Si) phase has vanished and crystallization event took place to a good extent. Journal of Engineering Science 11(1), 2020, 107-112

Prediction of the Energy Losses in Soft Magnetic Alloys Based on the Magnetic Objects Theory in the Case of the Uniform Magnetic Flux Penetration

2014 ◽  
Vol 792 ◽  
pp. 260-265
Author(s):  
Veronica Paltanea ◽  
Gheorghe Paltanea ◽  
Horia Gavrila
Keyword(s):  
Amorphous Ribbon ◽  
Rolling Direction ◽  
Low Frequency ◽  
Soft Magnetic Materials ◽  
Magnetic Polarization ◽  
Soft Magnetic ◽  
Silicon Iron ◽  
Soft Magnetic Alloys ◽  
Loss Prediction ◽  
Theoretical Assessment

We report an investigation and a theoretical assessment of energy loss prediction in crystalline and amorphous soft magnetic materials. There were tested a sample made from non-oriented silicon iron (NO FeSi) M800-65A, industrial type alloy, cut longitudinally to the rolling direction and a toroidal sample of Co67Fe4B14.5Si14.5amorphous ribbon. The losses behaviour of the crystalline NO FeSi strip was studied as function of frequency in the range of 5 Hz to 200 Hz at a given magnetic polarization (Jp) of 0.5 T and 1 T. In the case of the amorphous Co-based ribbon the losses variation was studied as function of frequency in the range of 5 Hz to 10 kHz at a given magnetic polarization of 20 mT. Using the concept of loss separation for the data analysis, in the approximation of linear magnetization law and low frequency limit, it can be considered in both cases, that the excess losses can be quantitatively assessed within the theoretical framework of the statistical loss model based on magnetic object theory.

scholarly journals Magnetoimpedance Effect in the Ribbon-Based Patterned Soft Ferromagnetic Meander-Shaped Elements for Sensor Application

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2468 ◽  
Author(s):  
Zhen Yang ◽  
Anna A. Chlenova ◽  
Elizaveta V. Golubeva ◽  
Stanislav O. Volchkov ◽  
Pengfei Guo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Chemical Etching ◽  
Amorphous Ribbon ◽  
Soft Magnetic Materials ◽  
Strong Impact ◽  
Soft Magnetic ◽  
Large Drop ◽  
Sensor Applications ◽  
Soft Ferromagnetic ◽  
Total Impedance

Amorphous and nanocrystalline soft magnetic materials have attracted much attention in the area of sensor applications. In this work, the magnetoimpedance (MI) effect of patterned soft ferromagnetic meander-shaped sensor elements has been investigated. They were fabricated starting from the cobalt-based amorphous ribbon using the lithography technique and chemical etching. Three-turn (S1: spacing s = 50 μm, width w = 300 μm, length l = 5 mm; S2: spacing s = 50 μm, width w = 400 μm, length l = 5 mm) and six-turn (S3: s = 40 μm, w = 250 μm, length l = 5 mm; S4: s = 40 μm, w = 250 μm and l = 8 mm) meanders were designed. The ‘n’ shaped meander part was denominated as “one turn”. The S4 meander possesses a maximum MI ratio calculated for the total impedance ΔZ/Z ≈ 250% with a sensitivity of about 36%/Oe (for the frequency of about 45 MHz), and an MI ratio calculated for the real part of the total impedance ΔR/R ≈ 250% with the sensitivity of about 32%/Oe (for the frequency of 50 MHz). Chemical etching and the length of the samples had a strong impact on the surface magnetic properties and the magnetoimpedance. A comparative analysis of the surface magnetic properties obtained by the magneto-optical Kerr technique and MI data shows that the designed ferromagnetic meander-shaped sensor elements can be recommended for high frequency sensor applications focused on the large drop analysis. Here we understand a single large drop as the water-based sample to analyze, placed onto the surface of the MI sensor element either by microsyringe (volue range 0.5–500 μL) or automatic dispenser (volume range 0.1–50 mL).

scholarly journals Nanocrystalline Soft Magnetic Iron-Based Materials from Liquid State to Ready Product

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 108
Author(s):  
Vladimir S. Tsepelev ◽  
Yuri N. Starodubtsev
Keyword(s):  
Critical Temperature ◽  
Heat Release ◽  
Chemical Elements ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Soft Magnetic Materials ◽  
Soft Magnetic ◽  
Magnetic Inhomogeneity ◽  
Core Losses ◽  
Temperature Dependences

The review is devoted to the analysis of physical processes occurring at different stages of production and application of nanocrystalline soft magnetic materials based on Fe–Si–B doped with various chemical elements. The temperature dependences of the kinematic viscosity showed that above a critical temperature, the viscosity of multicomponent melts at the cooling stage does not coincide with the viscosity at the heating stage. Above the critical temperature, the structure of the melt is more homogeneous, the amorphous precursor from such a melt has greater plasticity and enthalpy of crystallization and, after nanocrystallization, the material has a higher permeability. The most effective inhibitor elements are insoluble in α-Fe and form a smoothed peak of heat release during crystallization. On the other hand, the finest nanograins and the highest permeability are achieved at a narrow high-temperature peak of heat release. The cluster magnetic structure of a nanocrystalline material is the cause of magnetic inhomogeneity, which affects the shape of the magnetic hysteresis loop and core losses.

Characterization of Magnetic Transformation at Curie Temperature in Finemet-type Microwires by DSC

2012 ◽  
Vol 1408 ◽  
Author(s):  
Sergey Kaloshkin ◽  
Margarita Churyukanova ◽  
Victor Tcherdyntsev
Keyword(s):  
Curie Temperature ◽  
Amorphous Phase ◽  
Amorphous Alloys ◽  
Nanocrystalline Structure ◽  
Soft Magnetic Materials ◽  
Relaxation Processes ◽  
Soft Magnetic ◽  
Dsc Measurements ◽  
Time Dependencies

ABSTRACTFinemet-type amorphous alloys are good soft magnetic materials due to their amorphous-nanocrystalline structure with close to zero magnetostriction. A very sensitive method for controlling relaxation and crystallization processes in such alloys is proposed. It consists in precise DSC measurements of heat capacity peak in the vicinity of the Curie temperature TC. Time-temperature dependencies of TC for microwires in comparison with ribbon shaped amorphous alloys were studied. Relaxation of atomic structure of amorphous phase during annealing was accompanied by an increase of TC. σ-shaped time dependencies are characterized by at least two relaxation processes, corresponding apparent values of activation energy were estimated. Decomposition of amorphous phase and redistribution of components between amorphous phase and growing nanocrystals affect the shape and position of the DSC peak at TC as well.Study of microwires with glass coating revealed the influence of internal stress on the shape and position of the Curie peak on DSC curve: increase of internal strain tensions leads to suppression of the TC peak.

Lesson Study dan Implikasinya Terhadap Pembelajaran Berbasis Kurikulum Tingkat Satuan Pendidikan

2016 ◽  
Vol 1 ◽  
pp. 189-196
Author(s):  
Vian Harsution
Keyword(s):  
Learning Environment ◽  
Learning Process ◽  
Lesson Study ◽  
Learning Difficulties ◽  
Learning Needs ◽  
Democratic Leadership ◽  
Entrepreneurial Spirit ◽  
To Receive

Lesson study is a systematic, collaborative, and sustainable method of improving the quality of learning. Lesson study emphasizes the exploration of students’ learning needs; teacher openness towards learning difficulties encountered; the willingness of teachers to receive and provide advice and solutions to the difficulties encountered; and the consistency of the various parties to follow up the suggestions and solutions. Implementation of lesson study involving teachers, principals, and experts in the field of education. Kurikulum tingkat satuan pendidikan or abbreviated KTSP is operational curriculum formulated and implemented by each educational unit. KTSP has the characteristics, namely: giving broad autonomy to the educational unit, involving the community and parent participation, involving the democratic leadership of the principal, and require the support of a working team that is synergistic and transparent. KTSP based on the learning process, needs to be supported by a conducive learning environment and fun to be created by teachers.Teachers and principals in a professional, systematic and collaborative create an atmosphere that fosters independence, tenacity, entrepreneurial spirit, adaptive and proactive nature of the learning process. Thus, the learning needs of students who fulfilled optimally and professional ability of teacher who have increased on an ongoing basis, may usher in success – based learning KTSP. It means that the lesson study provides positive implications for the KTSP – based learning.

The Microbial Quality of a Wetland Reclamation Facility Used to Produce an Effluent for Unrestricted non-Potable Reuse

1999 ◽  
Vol 40 (4-5) ◽  
pp. 369-374 ◽  
Author(s):  
R. S. Fujioka ◽  
A. J. Bonilla ◽  
G. K. Rijal
Keyword(s):  
Fecal Coliform ◽  
Heterotrophic Bacteria ◽  
Fecal Indicator ◽  
Potable Reuse ◽  
Wetland Reclamation ◽  
Treated Sewage ◽  
Influent Water ◽  
Human Viruses ◽  
To Receive

An auxiliary Wetland Reclamation Facility (WRF) was constructed to receive stabilization pond treated sewage and further treat it with water hyacinth ponds, chemical flocculation, filtration and ultraviolet light disinfection. This was the first facility in Hawaii which was approved to produce the highest quality reclaimed water using alternative treatment schemes. We assessed the effectiveness of the WRF by monitoring water samples after each of the WRF treatment schemes for five genetically different groups of sewage borne microorganisms (fecal coliform, enterococci, C. perfringens, FRNA phage, total heterotrophic bacteria). The concentrations of all fecal indicator microoganisms, especially FRNA phase were low in the influent water to the WRF indicating that extended pond treatment may be especially effective in removing human viruses from sewage. The WRF treatment scheme was calculated to be able to reduce >99.99% of fecal coliform and therefore was able to produce an effluent meeting the non-potable, unrestricted reuse standard of a geometric means of <1 fecal coliform/100 ml.

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