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P. Pietrusiewicz, M. Nabiałek, M. Szota and K. Perduta

Microstructure and Soft Magnetic Properties of Fe61Co10Y8Me1B20 (Where Me = W, Zr or Nb) Amorphous Alloys

The microstructure and the soft magnetic properties of the multi-component Fe61Co10Y8Me1B20 amorphous alloys (where Me = W, Zr or Nb) have been investigated; the samples were in the form of ribbons of 3 mm width and 30 μm thickness. The samples were produced using a single-roller melt-spinning method. The alloy composition was investigated using an X-ray diffractometer. The amorphous nature of the entire volume of all the as-quenched samples was confirmed. From the magnetic measurements performed using the ‘LakeShore’ vibrating sample magnetometer, magnetic parameters such as: coercivity, saturation of the magnetization for the as-quenched samples were derived. All of the investigated alloys displayed good soft magnetic properties, making them perfect materials for magnetic cores. The core losses for different values of magnetic field and operating frequency were also measured. It was shown that the investigated alloys featured lower core losses than commercially-used classical FeSi steel.

Open access

P. Pietrusiewicz, M. Nabiałek, M. Szota, M. Dośpiał, K. Błoch, A. Bukowska and K. Gruszka

Abstract

In this paper the results of the structural and magnetic investigation of Fe61Co10Y8Zr1B20 alloy after solidification and isothermal annealing was presented. The isothermical annealing was carried out at 700 K for 1 h and 770 K for 3.5 h. For the structural investigation was performed by X-ray diffractometer equipped with a copper lamp. The results of (XRD) measurements showed the material in the state after the solidification and heat treatment is amorphous. Static hysteresis loops and initial magnetization curve was measured using vibrating magnetometer (VSM). The quality and quantity of structural defects in the sample after heat treatment was determined by indirect method using analyze the initial magnetization curve in accordance with the theory of Kronmüllera. These studies have shown that the annealing process has big influence to change significantly quantity of defects in amorphous structure as a result, there are changes of magnetic parameters such as saturation magnetization and field μ0Ms coercivity Hc.

Open access

M. Nabiałek, P. Pietrusiewicz, M. Szota, M. Dośpiał, J. Jędryka, K. Szota and S. Lesz

Evaluation of the Microstructure and Magnetic Properties of Fe73Me5Y3B19 (Where Me = Ti or Nb) Amorphous Alloys

The results of microstructure and magnetic properties studies of the amorphous Fe73Me5Y3B19 (where Me = Ti or Nb) alloys are presented The samples of the investigated alloys were produced in the form of ribbons with thickness of approximately 30 μm by unidirectional cooling of the liquid material on a rotating copper wheel. Both investigated alloys, in the as-quenched state, were fully amorphous which was verified using a ‘Bruker’ X-ray diffractometer. Static hysteresis loops, measured using ‘LakeShore’ vibrating sample magnetometer (VSM), were typical as for soft magnetic ferromagnets. The Fe73Nb5Y3B19 and Fe73Ti5Y3B19 alloys were characterized by relatively high values of saturation of the magnetization (1.25 T and 1.26 T, respectively) and low coercivity field (16 A/m and 47 A/m, respectively). The core losses obtained for the investigated alloys were significantly lower than for commercially used FeSi transformer steels. Both alloys also exhibited excellent time and temperature stability of the magnetic properties (within the investigated temperature range), as confirmed by measurements of magnetic susceptibility and its disaccommodation.

Open access

P. Pietrusiewicz, M. Nabiałek, M. Szota, M. Dośpiał, K. Błoch, J. Gondro and K. Gruszka

Abstract

The influence of isothermal annealing on the magnetisation process in strong magnetic fields of the amorphous Fe61Co10Y8Ni1B20 alloy ribbons was investigated. Samples in the form of ribbons were produced by rapid quenching of liquid alloy on a rotating copper wheel. In order to study the relaxation process, the investigated Fe61Co10Y8Ni1B20 samples were subjected to annealing below the crystallisation temperature at 700 K for 1 h and then at 770 K for 3.5 h. The structure of the samples was examined by X-ray diffraction measurements (XRD). It was found, that all of measured samples in the as-cast state and after thermal treatment, were amorphous. On the basis of virgin magnetisation curve analysis, the type, size and density of structural defects occurring in the investigated samples were determined. It was found that after the first stage of annealing, decay of linear defects (pseudo-dislocation dipoles) into smaller, more thermodynamically stable, point defects occurs. The presence of point like defects was also confirmed after the second stage of annealing.

Open access

M. Nabiałek, A. Dobrzanska-Danikiewicz, S. Lesz, P. Pietrusiewicz, M. Szota and M. Dospiał

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).

Open access

M. Nabiałek, P. Pietrusiewicz, M. Szota, A. Dobrzanska-Danikiewicz, S. Lesz, M. Dospiał, K. Błoch and K. Ozga

Abstract

In this paper, the results of the investigation into the fractured surface microstructure of the amorphous samples of Fe36Co36B19Si5Nb4 in the shape of rods of diameters: 1 mm, 2 mm and 3 mm in the as-cast state are presented. The samples were prepared by injection of molten alloy into cooled copper dies. The process of diffusion in the investigated material has a different speed depending on the temperature gradient within the volume of the rod. The atomic diffusion leads to the creation of different zones within the rod fracture: the zone in contact with the copper die, the intermediate fracture zone, and the zone in the vicinity of the rod core; the three zones have been found to exhibit different amorphous structures.

Open access

K. Gruszka, M. Nabiałek, M. Szota, K. Bloch, J. Gondro, P. Pietrusiewicz, A.V. Sandu, A.M. Mustafa Al Bakri, S. Walters, K. Walters, S. Garus, M. Dośpiał and J. Mizera

Abstract

The paper presents the results of structural and magnetic properties and thermal stability for a group of functional materials based on Fe61Co10Zr2.5Hf2.5Me2W2B20 (where Me = Mo, Nb, Ni or Y). Samples were obtained in the form of ribbons using melt-spinning method. The X-ray diffraction patterns of investigated samples confirmed their amorphous structure. Based on the analysis of DSC curves characteristic temperatures: glass forming temperature (Tg), crystallization temperature (Tx) and temperature range of the supercooled liquid ΔTx were determined. Small addition of transition metals elements has strong influence on magnetic and thermal parameters of studied materials. The comprehensive studies revealed that in terms of magnetic properties the Ni-addition resulted in highest reduction in coercivity and anisotropy field.