Influence of solidification speed on the structure and magnetic properties of Nd10Fe81Zr1B6 in the as-cast state

ABSTRACTAlloys of Pr-Fe-B-Cu were cast into Cu and stainless steel tubes. It could be seen that a preferred crystallographic orientation was obtained after cooling. Fine platelets of Pr2Fe1 4B matrix phase were formed, surrounded by various grain boundary phases, and there was a significant reduction in the amount of free Fe present, in comparison to conventional slab cast alloys. In order to improve the magnetic properties in the as-cast state, two alternative routes were used. The first involved a series of two step heat treatments to develop an improved microstructure. After an optimum heat treatment of 1000 'C for 24 hours + 500°C for 3 hours, significantly improved magnetic properties were obtained for a 17.5 % Pr alloy; Br = 752 mT, Hci = 613 kAm−1 and BHmax = 96 kJm−3. The second route involved a rapid upset forging [RUF] process, with a strain rate of 11.5 s−1, to hot deform the alloys. Following post-forging heat treatments, properties of Br = 966 mT, Hci = 780 kAm−3 and BHmax = 160 kJm−3 were obtained for a 15% Pr alloy. That nature of the improvements in properties as a result of heat treatments and RUF were investigated and are discussed in the present work.

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An Investigation Into The Effect Of Isothermal Annealing On Magnetic Properties In The Alloy: Fe64Co10Y6B20

Archives of Metallurgy and Materials ◽

10.1515/amm-2015-0337 ◽

2015 ◽

Vol 60 (3) ◽

pp. 1987-1992

Author(s):

M. Nabiałek

Keyword(s):

Magnetic Properties ◽

Isothermal Annealing ◽

Structural Defects ◽

Bulk Amorphous Alloy ◽

Cast State ◽

Soft Magnetic ◽

Scanning Calorimetry ◽

Saturation Magnetisation ◽

Crystallisation Temperature ◽

Saturation Theorem

AbstractThis work presents the results of investigations into the structural and magnetic properties of the bulk amorphous alloy: Fe64Co10Y6B20. The structure, thermal stability and magnetic properties of the alloy were studied using: X-ray diffractometry, differential scanning calorimetry (DSC), and a vibrating sample magnetometer (VSM), respectively. The investigations were performed on samples of the alloy in both the ‘as-cast’ state, and the state resulting from a process of isothermal annealing at a temperature of 750 K for 30 minutes.The aim of the conducted studies was to relax the structure and improve the soft magnetic properties of the investigated alloy. The results show that annealing the alloy at a temperature well below its crystallisation temperature leads to an increase in the value of the saturation magnetisation and a decrease in the value of the coercivity. Utilising the ‘approach to the ferromagnetic saturation’ theorem, the nature of structural defects within the investigated material has been established. For both ‘as-cast’ and isothermally-annealed samples, the magnetisation process has been found to be connected with the existence of linear structural defects.

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Structure and Soft Magnetic Properties of the Amorphous Alloys: Fe61Co10Ti3-xY6+xB20 (x = 0, 1)

Archives of Metallurgy and Materials ◽

10.1515/amm-2016-0080 ◽

2016 ◽

Vol 61 (1) ◽

pp. 445-450

Author(s):

K. Błoch

Keyword(s):

Magnetic Properties ◽

Amorphous Alloys ◽

Major Effect ◽

Exothermic Peak ◽

Soft Magnetic Properties ◽

X Ray Diffraction ◽

Cast State ◽

Soft Magnetic ◽

Two Peaks ◽

Thermal Stability Of

This paper presents studies relating to the structure, soft magnetic properties and thermal stability of the following bulk amorphous alloys: Fe61Co10Ti3-xY6+xB20 (x = 0, 1). On the basis of the performed X-ray diffraction studies and Mössbauer spectroscopy, it was found that investigated samples were amorphous in the as-cast state. The DSC curve obtained for Fe61Co10Ti2Y7B20 alloy exhibited one exothermic peak, while for the Fe61Co10Ti3Y6B20 sample, two peaks were distinguishable. The change in the chemical structure of the investigated alloys has a major effect on their soft magnetic properties; especially on coercivity and saturation magnetization. On the basis of the magnetization curves analysis, the spin wave stiffness parameter Dsp were determined for the investigated alloys.

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Structural, Magnetic and Crystallization Study of Fe-Based Bulk Metallic Glasses

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.203-204.288 ◽

2013 ◽

Vol 203-204 ◽

pp. 288-291 ◽

Cited By ~ 5

Author(s):

Rafał Babilas ◽

Ryszard Nowosielski ◽

Wirginia Pilarczyk ◽

Grzegorz Dercz

Keyword(s):

Magnetic Properties ◽

Magnetic Permeability ◽

Metallic Glasses ◽

Bulk Metallic Glasses ◽

Annealing Process ◽

Bulk Amorphous Alloy ◽

X Ray Diffraction ◽

Cast State ◽

Scanning Calorimetry ◽

Crystallization Study

The work presents the structural, thermal and magnetic properties analysis of Fe72B20Si4Nb4 bulk metallic glasses in as-cast state and crystallization study of bulk amorphous alloy after annealing process. The studies were performed on bulk metallic glasses in of rods form with diameter of 1,5 and 2 mm. The structure analysis of the samples in as-cast state and phase analysis of studied alloy after annealing process was carried out by the X-ray diffraction (XRD) methods. Mössbauer spectroscopy (MS) was also used to investigate the local structure for studied bulk metallic glasses. Thermal properties associated with glass transition, onset and peak crystallization temperatures was examined by differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained initial magnetic permeability and disaccommodation of magnetic permeability.

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Investigations on the Magnetic Properties of High-Coercivity (Nd1−xFex)90Al10 Bulk Amorphous Alloys

MRS Proceedings ◽

10.1557/proc-674-u2.7 ◽

2001 ◽

Vol 674 ◽

Cited By ~ 8

Author(s):

N. Lupu ◽

H. Chiriac ◽

A. Takeuchi ◽

A. Inoue

Keyword(s):

Magnetic Properties ◽

Cooling Rate ◽

Amorphous Alloys ◽

Magnetic Measurements ◽

High Coercivity ◽

Magnetic Clusters ◽

Cast State ◽

Fe Content ◽

Mould Casting ◽

Microstructure And Magnetic Properties

ABSTRACTBulk rods with diameters up to 3 mm prepared by suction casting and respectively mould casting and melt-spun amorphous ribbons with thicknesses in the range 25 – 150 μm with compositions Nd90−xFexAl10 (x = 35; 40; 45; 50) were investigated by XRD, DSC and magnetic measurements in the temperature range 5 – 600 K. The microstructure and magnetic properties are strongly dependent on the cooling rate, preparation process and Fe content. The large values of the coercive field, which amount to 320 kA/m in the as-cast state as well as the increase with decrease of the temperature and cooling rate result from the formation of very small metastable or nonequilibrium magnetic clusters.

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Effect of Cooling Rate on Magnetic Properties, Size and Type of Structural Defects in the Volume of Bulk Amorphous Fe36Co36B19Si5Nn4 Alloy in the Form of Rods of Various Diameters

Archives of Metallurgy and Materials ◽

10.2478/amm-2014-0043 ◽

2014 ◽

Vol 59 (1) ◽

pp. 263-268 ◽

Cited By ~ 2

Author(s):

M. Nabiałek ◽

A. Dobrzanska-Danikiewicz ◽

S. Lesz ◽

P. Pietrusiewicz ◽

M. Szota ◽

...

Keyword(s):

Magnetic Properties ◽

Liquid Alloy ◽

Magnetization Curve ◽

Amorphous State ◽

Structural Defects ◽

Initial Magnetization ◽

Type Size ◽

Solidification Speed ◽

Determining Factor ◽

Magnetization Behavior

Abstract This paper presents the results of microstructure and magnetic properties analysis for bulk amorphous samples of Fe36Co36B19Si5Nb4 alloy in the form of rods of 1 mm, 2 mm, and 3 mm diameters in the as-cast state, produced using the method of injecting liquid alloy into cooled copper mold. The main purpose of the research was to examine the effect of solidification speed of the liquid material into amorphous state on the shape of initial magnetization curve as well as to determine the type and size of structural defects occurring in the volume of the material. In order to achieve these objectives, the magnetization measurements were carried out, which according to H. Kronmüller’s theory on magnetization behavior near the area called reaching the ferromagnetic saturation, allow to determine the type, size, and surface density of structural defects occurring in the volume of the sample. The analysis of reduced magnetization curves indicates that solidification speed of the liquid alloy into the amorphous state is the main determining factor for the shape of initial magnetization curve and for the type and size of structural defects formed in the sample, which affects such magnetic parameters as: coercive field (HC) or saturation magnetization (MS).

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Influence of the as-cast state on the crystallization process and magnetic properties for FeSiBCuNb wires

IEEE Transactions on Magnetics ◽

10.1109/20.334224 ◽

1994 ◽

Vol 30 (6) ◽

pp. 4794-4796 ◽

Cited By ~ 7

Author(s):

P. Marin ◽

A.O. Olofinjana ◽

M. Vazquez ◽

H.A. Davies

Keyword(s):

Magnetic Properties ◽

Crystallization Process ◽

Cast State

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Structural and Magnetic Studies of Bulk Nanocomposite Magnets Derived from Rapidly Solidified Pr-(Fe,Co)-(Zr,Nb)-B Alloy

Materials ◽

10.3390/ma13071515 ◽

2020 ◽

Vol 13 (7) ◽

pp. 1515 ◽

Cited By ~ 1

Author(s):

Katarzyna Pawlik ◽

Piotr Pawlik ◽

Jerzy J. Wysłocki ◽

Waldemar Kaszuwara

Keyword(s):

Magnetic Properties ◽

Volume Fraction ◽

Hysteresis Loops ◽

Cast State ◽

Magnetic Studies ◽

Phase Constitution ◽

Complementary Method ◽

Crystallite Sizes ◽

Diffraction Patterns ◽

Rapidly Solidified

In the present study, the phase constitution, microstructure and magnetic properties of the nanocrystalline magnets, derived from fully amorphous or partially crystalline samples by annealing, were analyzed and compared. The melt-spun ribbons (with a thickness of ~30 µm) and suction-cast 0.5 mm and 1 mm thick plates of the Pr9Fe50Co13Zr1Nb4B23 alloy were soft magnetic in the as-cast state. In order to modify their magnetic properties, the annealing process was carried out at various temperatures from 923K to 1033K for 5 min. The Rietveld refinement of X-ray diffraction patterns combined with the partial or no known crystal structures (PONKCS) method allowed one to quantify the component phases and calculate their crystalline grain sizes. It was shown that the volume fraction of constituent phases and their crystallite sizes for the samples annealed at a particular temperature, dependent on the rapid solidification conditions, and thus a presence or absence of the crystallization nuclei in the as-cast state. Additionally, a thermomagnetic analysis was used as a complementary method to confirm the phase constitution. The hysteresis loops have shown that most of the samples exhibit a remanence enhancement typical for the soft/hard magnetic nanocomposite. Moreover, for the plates annealed at the lowest temperatures, the highest coercivities up to ~1150 kA/m were measured.

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Microstructure and High-Field Magnetic Properties of Fe-Based Bulk Amorphous Alloys

Revista de Chimie ◽

10.37358/rc.18.4.6241 ◽

2018 ◽

Vol 69 (4) ◽

pp. 982-985 ◽

Cited By ~ 1

Author(s):

Katarzyna Bloch

Keyword(s):

Magnetic Properties ◽

Magnetic Fields ◽

Amorphous Alloys ◽

High Field ◽

Structural Investigation ◽

Hysteresis Loops ◽

Cast State ◽

X Ray ◽

Bulk Amorphous Alloys ◽

High Field Magnetization

In this paper the results of the structural and magnetic properties for bulk amorphous alloys Fe65Co10Y5B20 and Fe63Co10Y7B20 were presented. For the structural investigation was performed by X-ray diffractometry and Mossbauer spectroscopy. It was found that investigated samples were amorphous in the as-cast state. The magnetisation was measured within magnetic fields ranging from 0 to 2T using a vibrating sample magnetometer (VSM). On the basis of the hysteresis loops, the saturation magnetization value and the coercive field were determined.The investigation of the �magnetisation in the area close to ferromagnetic saturation� showed that the magnetisation process in strong magnetic fields is connected with point defects and Holstein-Primakoff paraprocess. Analysis of the high-field magnetization curves has facilitated the calculation of the spin wave stiffness parameter.

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