Nanocrystalline soft magnetic ribbon with α″-Fe16N2 nanocrystallites embedded in amorphous matrix

2008 ◽  
Vol 320 (21) ◽  
pp. 2752-2754 ◽  
Author(s):  
Wensheng Liu ◽  
Jiancheng Tang ◽  
Youwei Du
Keyword(s):  
Amorphous Matrix ◽  
Soft Magnetic

Temperature dependence of the soft magnetic character of Fe73.5Cu1Nb3Si13.5B9 amorphous and nanocrystalline alloys

2003 ◽  
Vol 18 (5) ◽  
pp. 1035-1038 ◽  
Author(s):  
J. Gonzáz
Keyword(s):  
Amorphous Alloy ◽  
Current Density ◽  
Curie Point ◽  
Amorphous Matrix ◽  
Body Centered Cubic ◽  
Soft Magnetic ◽  
Current Densities ◽  
Two Phases ◽  
Residual Amorphous Matrix ◽  
Magnetic Hardness

Results on microstructure and coercivity of current-annealed Fe73.5Cu1Nb3Si13.5B9 amorphous alloy treated at different current densities (12–56 A/mm2) and duration (0.5–720 min) are presented. Saturation magnetization and coercivity dependencies with the current density of the nanocrystalline samples is explained by considering the presence of two phases: nanocrystals of Fe(Si) body-centered cubic (bcc) grains and the residual amorphous matrix. An increase in the magnetic hardness observed when the sample was heated by current densities, giving rise to an increase in the sample temperature above the Curie point of the residual amorphous matrix, could be ascribed to exchange and dipolar decoupling of the Fe(Si)-bcc grains.

scholarly journals Grain refinement mechanism of soft-magnetic alloys with nanocrystals embedded in amorphous matrix

2020 ◽  
Vol 9 (3) ◽  
pp. 3558-3565
Author(s):  
Tao Liu ◽  
Hua Zhang ◽  
Fengyu Kong ◽  
Anding Wang ◽  
Yaqiang Dong ◽  
...  
Keyword(s):  
Grain Refinement ◽  
Amorphous Matrix ◽  
Soft Magnetic ◽  
Magnetic Alloys ◽  
Soft Magnetic Alloys ◽  
Refinement Mechanism

Obtaining soft magnetic powder composites of the system ferromagnetic – diamagnetic

2019 ◽  
pp. 44-49
Author(s):  
M. A. Korkina ◽  
E. A. Samodelkin ◽  
B. V. Farmakovsky ◽  
O. V. Vasilyeva ◽  
P. A. Kuznetsov ◽  
...  
Keyword(s):  
Powder Material ◽  
High Frequency ◽  
Composite Powder ◽  
Amorphous Matrix ◽  
Frequency Range ◽  
Soft Magnetic ◽  
Powder Composition ◽  
Composite Powder Material ◽  
Absorbing Materials ◽  
Powder Composites

A method has been developed for producing a powder material of the ferromagnetic – diamagnetic system, intended for the manufacture of composite radar absorbing materials and coatings in the ultra-high frequency range. Composite powder material with a polymer diamagnetic matrix reinforced with a ferromagnetic nanocrystalline hardener is obtained by the method of ultrafast mechanosynthesis. The proposed technology of superfast mechanosynthesis allows to obtain a powder composition where each particle is a single mechanically connected system, while reducing the degree of amorphousness (no more than 80%) by maintaining the proportion of nanocrystalline precipitates in the amorphous matrix and, accordingly, increasing the magnetic permeability (up to 90 or more). The composite powder of the ferromagnetic – diamagnetic system thus obtained can be used to obtain radar absorbing materials with high shielding efficiency and a large absorption coefficient (at least 25 dB) in the frequency range from 1 MHz to 40 GHz.

scholarly journals Study of Structure and Properties of Fe-Based Amorphous Ribbons after Pulsed Laser Interference Heating

2020 ◽  
Vol 29 (10) ◽  
pp. 6277-6285
Author(s):  
Olaf Czyż ◽  
Jan Kusiński ◽  
Agnieszka Radziszewska ◽  
Zhongquan Liao ◽  
Ehrenfried Zschech ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Laser Heating ◽  
Amorphous Matrix ◽  
Dendritic Structure ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Structure And Properties ◽  
Soft Magnetic ◽  
Tem Analysis ◽  
Amorphous Ribbons

AbstractThe paper is devoted to the study of microstructural and magnetic properties of the Fe-based amorphous ribbons after interference pulsed laser heating. The ternary amorphous alloy FeSiB, as well as the multi-component alloys FeCuSiB and FeCuNbSiB, was subjected to laser pulses to induce crystallization in many microislands simultaneously. Structure and properties changes occurred in laser-heated dots. Detailed TEM analysis from a single dot shows the presence of FeSi(α) nanocrystals in the amorphous matrix. The FeSiB alloy is characterized after conventional crystallization by a dendritic structure; however, the alloys with copper as well copper and niobium additions are characterized by the formation of equiaxed crystals in the amorphous matrix. Amorphous alloys before and after the laser heating are soft magnetic; however, conventional crystallization leads to a deterioration of the soft magnetic properties of the material.

scholarly journals Influence of Milling Time on the Homogeneity and Magnetism of a Fe70Zr30 Partially Amorphous Alloy: Distribution of Curie Temperatures

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 490
Author(s):  
Alejandro F. Manchón-Gordón ◽  
Jhon J. Ipus ◽  
Javier S. Blázquez ◽  
Clara F. Conde ◽  
Alejandro Conde
Keyword(s):  
Amorphous Alloy ◽  
Crystal Size ◽  
Milling Time ◽  
Magnetocrystalline Anisotropy ◽  
Amorphous Matrix ◽  
Magnetic Behavior ◽  
Magnetic Response ◽  
Soft Magnetic ◽  
Mechanically Alloyed ◽  
Curie Temperatures

In this work, the mechanically alloyed Fe70Zr30 (at. %) composition has been used to study the influence of milling time on its homogeneity and magnetic properties. The microstructure and Fe environment results show the formation of an almost fully amorphous alloy after 50 h of milling in a mixture of pure 70 at. % Fe and 30 at. % Zr. The soft magnetic behavior of the samples enhances with the increase of the milling time, which is ascribed to the averaging out of the magnetocrystalline anisotropy as the crystal size decreases and the amorphous fraction increases. The formation of a non-perfectly homogenous system leads to a certain compositional heterogeneity, motivating the existence of a distribution of Curie temperatures. The parameters of the distribution (the average Curie temperature, T C ¯ , and the broadening of the distribution, ∆ T C ) have been obtained using a recently reported procedure, based on the analysis of the approach towards the saturation curves and the magnetocaloric effect. The decrease of ∆ T C and the increase of T C ¯ with the milling time are in agreement with the microstructural results. As the remaining α-Fe phase decreases, the amorphous matrix is enriched in Fe atoms, enhancing its magnetic response.

The Effect of Quenching Rate on Structure and Soft Magnetic Properties of High Bs Fe-Based Nanocrystalline Alloys

2013 ◽  
Vol 829 ◽  
pp. 78-81
Author(s):  
Farzad Hosseini-Nasb ◽  
Ali Beitollahi ◽  
Mohammad Kazem Moravvej-Farshi
Keyword(s):  
Grain Size ◽  
Melt Spinning ◽  
Amorphous Matrix ◽  
Wheel Speed ◽  
Soft Magnetic Materials ◽  
Soft Magnetic ◽  
Quenching Rate ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
Good Agreement

Recently some nanocrystalline soft magnetic materials containing nanosized α-Fe grains have been obtained by crystallization of amorphous melt-spun ribbons. These structures are nanocomposites in which nanosized grains are distributed within an amorphous matrix. The soft magnetic ribbons composed of Fe80B10Si8Nb1Cu1 alloy were prepared by melt spinning method with different quenching rates (wheel speed of 10, 20 and 40 m/s). The XRD results exhibit an increase in the copper wheel speed (quenching rate) causes the fraction of crystallinity and grain size to decrease. The grain size varies in the range of 20 to 200 nm that is in good agreement with TEM results. The VSM results show that these nanostructured samples exhibit coercivity in the range of 10 to 30 A/m and magnetic saturation in the range of 1.5 to 1.7 T.

Thermomagnetic Analysis of the Crystallization in Soft Magnetic Nanocrystalline Alloys

2020 ◽  
Vol 846 ◽  
pp. 67-71
Author(s):  
Vladimir S. Tsepelev ◽  
Yuri N. Starodubtsev ◽  
K.M. Wu ◽  
Nadezhda P. Tsepeleva
Keyword(s):  
Amorphous Matrix ◽  
Chemical Elements ◽  
Amorphous State ◽  
Simultaneous Recording ◽  
Soft Magnetic ◽  
Crystallization Peak ◽  
Thermomagnetic Analysis ◽  
The Core ◽  
Si Nanocrystals ◽  
Curie Temperatures

In this work, we investigated the dynamics of nanocrystallization from the amorphous state of the Fe72.5Cu1Nb2Mo1.5Si14B9 alloy together with magnetic phase transformations. The thermomagnetic analysis was performed with the simultaneous recording of the temperature inside the core by a thermocouple and the inductance of the winding wound over the core. It was found that the permeability of the core after the crystallization peak first increases rapidly, and then decreases and stabilizes at some level. Permeability growth begins at a temperature that coincides with the Curie point of the Fe80Si20 solid solution. A decrease in permeability was associated with stabilization of the structure of the amorphous and crystalline phases upon cooling. With decreasing temperature, the active redistribution of chemical elements is suppressed, and silicon atoms occupy a stable position in the crystal lattice of iron. Nanocrystalline cores have different Curie temperatures in the state after the peak of crystallization and 300 seconds after the peak. This indicates the continuation of the diffusion of silicon from the amorphous matrix into Fe-Si nanocrystals for some time after the crystallization peak.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

Microstructure in soft magnetic E3 (S1, Al) (Sendust) alloys

1988 ◽  
Vol 46 ◽  
pp. 770-771
Author(s):  
June D. Kim
Keyword(s):  
Electron Microscopy ◽  
Magnetic Properties ◽  
Ternary Phase Diagram ◽  
Vertical Tube ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Soft Magnetic ◽  
Quenching Temperature ◽  
Thin Foils ◽  
Vertical Tube Furnace

Iron-base alloys containing 8-11 wt.% Si, 4-8 wt.% Al, known as “Sendust” alloys, show excellent soft magnetic properties. These magnetic properties are strongly dependent on heat treatment conditions, especially on the quenching temperature following annealing. But little has been known about the microstructure and the Fe-Si-Al ternary phase diagram has not been established. In the present investigation, transmission electron microscopy (TEM) has been used to study the microstructure in a Sendust alloy as a function of temperature.An Fe-9.34 wt.% Si-5.34 wt.% Al (approximately Fe3Si0.6Al0.4) alloy was prepared by vacuum induction melting, and homogenized at 1,200°C for 5 hrs. Specimens were heat-treated in a vertical tube furnace in air, and the temperature was controlled to an accuracy of ±2°C. Thin foils for TEM observation were prepared by jet polishing using a mixture of perchloric acid 15% and acetic acid 85% at 10V and ∼13°C. Electron microscopy was performed using a Philips EM 301 microscope.

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