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1

Approach to ferromagnetic saturation for amorphous Fe-based alloy

Jeż B., Nabiałek M., Jeż K.

Prace Instytutu Metalurgii Żelaza

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2018

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T. 70, nr 3

40--45

EN

The paper presents the results of research on the structure and selected properties of magnetic alloys based on Fe. The alloy with the chemical composition Fe36Co36Y8B20 was produced using two methods: forcing and sucking the liquid alloy into a copper mould. The alloy was cast in the form of 10 mm × 5 mm × 0.5 mm tiles. The structure of the obtained alloys was examined using X-ray diffraction. The measured diffractograms are typical for amorphous materials. Using the Faraday magnetic balance, the magnetic saturation polarisation curves as a function of temperature were recorded. The Curie temperature of the created alloys, which amounted to approximately 750 K, was determined on the basis of numerical analysis. The original magnetisation curves and static magnetic hysteresis loops were measured using a vibration magnetometer. The produced alloys had a saturation magnetisation of about 1.1T and a coercive field value of about 200 A/m. The curves of primary magnetisation were analysed using H. Kronmüller’s theory. It was found that the magnetising process in the area called the ‘approach to ferromagnetic saturation’ is related to the rotation of the magnetisation vector around the linear defects of the structure.

PL

W pracy zamieszczono wyniki badań struktury i wybranych właściwości magnetycznych stopów na bazie Fe. Stop o składzie chemicznym Fe36Co36Y8B20 wytworzono dwiema metodami: wtłaczania oraz zasysania ciekłego stopu do miedzianej formy. Stop odlewano w postaci płytek o wymiarach 10 mm × 5 mm × 0,5 mm. Strukturę otrzymanych stopów badano przy użyciu dyfrakcji rentgenowskiej. Zmierzone dyfraktogramy są typowe jak dla materiałów amorficznych. Przy użyciu wagi magnetycznej Faraday’a zarejestrowano krzywe magnetycznej polaryzacji nasycenia w funkcji temperatury. Na podstawie analizy numerycznej krzywych wyznaczono temperaturę Curie wytworzonych stopów, która wyniosła około 750 K. Przy użyciu magnetometru wibracyjnego zmierzono pierwotne krzywe magnesowania oraz statyczne pętle histerezy magnetycznej. Wytworzone stopy posiadały magnetyzację nasycenia około 1,1T oraz wartość pola koercji około 200 A/m. Wykorzystując teorię H. Kronmüllera, przeprowadzono analizę krzywych pierwotnego magnesowania. Stwierdzono, że proces magnesowania w obszarze zwanym podejściem do ferromagnetycznego nasycenia związany jest z obrotem wektora magnetyzacji wokół liniowych defektów struktury.

2

Effect of Selected Alloying Elements on the Soft-Magnetic and Mechanical Properties of Injection-Cast Fe61Co10Y8Me1B20 Alloys (Me = Nb, W or Mo)

Pietrusiewicz P., Nabiałek M.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 1

61--64

EN

Properties of amorphous alloys differ from each other when they are produced at different cooling rates and from different chemical compositions. This paper presents studies of the magnetic and mechanical properties of Fe61Co10 Y8 Nb1 B20, Fe61 Co10 Y8 -W1 B20 and Fe61 Co10 Y8 Mo1 B20 alloys, in the form of plates, produced by the injection of liquid alloy into a copper mould. Based on the performed studies, it was found that the substitution of 1% non-magnetic additive into the alloy composition had little effect, as regards the values of saturation magnetization (Ms ) and Curie temperature (Tc ). However, in the case of the coercive field, the sample with the W addition had a value almost half that of the other two alloys. For all of the studied alloys, the microhardness was about 1180 μHv100, i.e. significantly higher than for the same materials in the crystalline state.

3

Porównanie jakości soczewek z powłokami antyrefleksyjnymi na podstawie odporności na ścieranie oraz transmisji światła w zakresie światła widzialnego

Jeż B., Nabiałek M.

Przetwórstwo Tworzyw

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2017

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T. 23, Nr 2 (176)

117--122

PL

W niniejszym opracowaniu przedstawiono wyniki badań dotyczących jakości organicznych soczewek okularowych z powłokami antyrefleksyjnymi dostępnych na rynku oftalmicznym. Za kryteria jakościowe uznano dwie bardzo istotne cechy soczewek: transmisję światła oraz odporność soczewek na ścieranie. Badania transmisji światła wykonano za pomocą spektrofotometru natomiast badania odporności na ścieranie przeprowadzono oscylacyjnym testerem ścieralności. Uzyskane wyniki transmisji światła odniesiono do nieuszlachetnionej soczewki natomiast wyniki pomiaru odporności na ścieranie odniesiono do soczewki mineralnej. Uzyskane rezultaty pokazują znaczną różnicę w poziomie jakości soczewek posiadających podobne powłoki, nie stwierdzono szczególnego wpływu powłok hydro i oleofobowych na odporność na ścieranie oraz transmisję światła.

EN

This paper presents the results of research the quality of organic spectacle lenses with anti-reflex coatings available on ophthalmic commercially. For qualitative criteria were considered two very important characteristics of the lenses: light transmission and resistance to abrasion lenses. Research of light transmission was performed using a spectrophotometer while research of abrasion resistance was carried out oscillating abrasion tester. The results was related to the light transmission of the lens not ennobled and the results of measurement of abrasion resistance was related to lens mineral. The results show a significant difference in the level of quality lenses having similar coatings, there was no particular impact hydro and oleophobic coating for abrasion resistance and light transmission.

4

Microstructure and Soft Magnetic Properties of Fe-Zr-(Pt)-Nb-Cu-B Amorphous Alloys

Gondro J., Błoch K., Nabiałek M., Walters S.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 2A

707--710

EN

This paper presents the results of investigations into the microstructure and magnetic properties of Fe86Zr7Nb1Cu1B5, Fe82Zr7Nb2Cu1B8 and Fe81Pt5Zr7Nb1Cu1B5 alloys. The alloys were investigated in their as-quenched state, in the form of thin ribbons with approximate dimensions as follows: width 3 mm and thickness 20 μm. The investigations were performed utilizing Mössbauer spectrometry and X-ray diffractometry. Also, an evaluation of the low-field magnetic susceptibility and measurements of the magnetization versus temperature and magnetizing field were performed.

5

Application of computed tomography for an analysis of composite with fine dispersive reinforcement made of the Fe65Co10Ni3W2B20 alloy

Szlązak K., Siejka A., Szota M., Nabiałek M., Łukaszewicz A., Klimas J., Pietrusiewicz P., Błoch K.

Archives of Materials Science and Engineering

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2017

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Vol. 83, nr 1

17--22

EN

Purpose: The paper presents the results of microstructure and mechanical properties of composites resulting from a combination of powders of metallic glasses with an epoxy resin (Epidian 100). The study was performed using computed tomography. Design/methodology/approach: The filler used was made of a Fe65Co10Ni3W2B20 amorphous alloy based on, showing in the state after the formation the soft magnetic properties. The aim of the study was to determine the effect of the fraction of the composite powders on the microstructure parameters (mean pore diameter and pore volume fraction) and the properties of the obtained composites. Findings: Based on the survey it was found out that size fraction used does not affect the value of the modulus of elasticity linear composites studied. It was also shown that the composites analysed in an attempt to compress the cross cracked grain boundaries. The influence fraction powders and change the share of the pore size depending on the fraction of the filler. Research limitations/implications: No studies of the magnetic properties determine the usefulness of these materials in the electronics industry. Practical implications: Practical implications are to size the test specimens in the limited range of tests. In the future, it is planned to produce samples with a larger diameter. Originality/value: The paper presents a new group of composites-based metallic glasses conditions characterised by good properties produced a simple and inexpensive method.

6

The dependence of the functional properties of the nanocomposite with matrix made of Epidian 100 resin due to size of reinforcement made of Fe67Co10Ni1W2B20 alloy

Siejka A., Szota M., Nabiałek M., Pietrusiewicz P., Łukaszewicz A., Klimas J., Błoch K.

Journal of Achievements in Materials and Manufacturing Engineering

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2016

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Vol. 77, nr 2

64--68

EN

Purpose: Objective of the paper was to determine the effect of particle size fraction for the mechanical properties of powders and magnetic fields produced powder consisting of ironbased alloys and an epoxy resin (trade name Epidian 100) which was obtained as a result of press. Design/methodology/approach: Samples were produced by the method of singleunilateral pressing. To achieve the pursued objective, the following tests were performed: microstructural observations – light microscope, roughness tests, statistical the hysteresis loops. Findings: On the basis of the research it can be stated that with the increase in the size fraction of the reinforcement of composites increased their roughness and greater was their density. In addition, with the increase in the size fraction of the reinforcement of composites increased the field coercivity, while decreasing saturation magnetisation. Research limitations/implications: The study not specified time and the influence of baling pressure on the mechanical properties and magnetic properties of composites produced using the single-uniaxial press. Practical implications: The division into three fractions powder using a sieve analysis did not allow for adequate separation of powders. In each fraction were small particles. In the future, it will be used a long period of time sieving powders. Originality/value: The paper presents new method producing magnetic composites, where possible was give shape by using epoxy resin.

7

The Influence of Heat Treatment on the Magnetization Process (within Strong Magnetic Fields) for the Alloy: Fe61Co10Y8Cu1B20

Gruszka K., Nabiałek M., Błoch K.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

499--502

EN

Samples of Fe61Co10Y8Cu1B20 alloy were investigated in the ‘approach to ferromagnetic saturation’ region by using the Kronmüller method. The amorphous material was obtained by radially cooling the molten alloy under a protective atmosphere of inert gas. Following this manufacturing process, static magnetic hysteresis loops were measured for samples, before and after a controlled isothermal annealing process, using a LakeShore vibrating magnetometer (VSM). From analysis of the primary magnetization curves, the distribution of structural defects and the average exchange distance for these defects were determined.

8

Reduced Glass-Transition Temperature versus Glass-Forming Ability in FeCoB-Based Amorphous Alloys

Nabiałek M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

1957--1962

EN

This work presents studies concerning the relationship between reduction of glass transition temperature Trg and the glass-forming ability of FeCoB-based alloys. On the basis of theoretical considerations, Turnbull [1] determined the reduced glass transition temperature (Tg/Tl) as being 2/3 of the Vogel–Fulcher–Tammann (VFT) temperature; since then, continuous research has been carried out, aiming to calculate the Trg parameter and describe its relationship with glass-forming ability. In the majority of research papers, the reduced glass transition temperature is calculated from the relationship Tg/Tm, proposed by Uhlmann and Davies [2, 3]. On the basis of differential scanning calorimetry (DSC) studies, undertaken in this current work, the values of the following temperatures have been found: Tg, Tx, Tm and Tl, in addition to the temperature ranges: ΔTx, ΔTm and ΔTl. The correlation between: Tg/Tm, Tg/Tl and the glass-forming ability also has been discussed. Finally, for the investigated alloys, it has been found that the relationship proposed by Turnbull is reliable over a wide range of ΔTm.

9

Mathematical Modelling of Thermo-Elasto-Plastic Problems and the Solving Methodology on the Example of the Tubular Section Forming Process

Michalczyk J., Nabiałek M., Szota M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 3

1655--1662

EN

The paper presents the results of numerical studies based on a mathematical model determined by the stress-strain state examination method. Numerical computations for two steel grades, namely H40 and C45, were made at similar strain and process rate parameters. As a result of the studies, the distribution of elastic and plastic zones was obtained, while the tube hollow drawing force was verified experimentally. The distribution of longitudinal, radial and circumferential stresses and, after the drawing operation, the distribution of residual stresses in the tube cross-section were also obtained.

10

Influence of the Quenching Rate on the Structure and Magnetic Properties of the Fe-Based Amorphous Alloy

Nabiałek M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

439--444

EN

This paper presents the results of investigations into the structure, microstructure and magnetic properties of Fe61Co10Y8W1B20 amorphous alloy. The alloy samples were in two physical forms: (1) plates of approximate thickness 0.5 mm (so-called bulk amorphous alloys) and (2) a ribbon of approximate thickness 35 μm (so-called classic amorphous alloy). The investigations comprised: X-ray diffractometry, Mössbauer spectrometry, transmission electron microscopy, and selected magnetic measurements; all of the investigations were carried out on samples in the as-quenched state. Analysis of the obtained SEM and TEM images, X-ray diffraction patterns, Mössbauer spectrometry results and measurements of the magnetisation in a high magnetic field facilitated collectively the detailed description of the structure of the investigated alloy, which was found to depend on the quenching speed.

11

Curie Temperature and Microstructural Changes Due to the Heating Treatment of Magnetic Amorphous Materials

Gondro J., Błoch K., Brągiel P., Nabiałek M., Szota M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

451--456

EN

Three distinct alloys: Fe86Zr7Nb1Cu1B5, Fe82Zr7Nb2Cu1B8, and Fe81Pt5Zr7Nb1Cu1B5 were characterized both magnetically and structurally. The samples, obtained with spinning roller method as a ribbons 3 mm in width and 20 μm thick, were investigated as-quenched and after each step of a multi steps heating treatment procedure. Each sample was annealed at four steps, fifteen minutes at every temperature, starting from 573K+600K up to +700K depending on type of alloy. Mössbauer spectroscopy data and transmission electron microscope (HRE M) pictures confirmed that the as-quenched samples are fully amorphous. This is not changed after the first stages of treatment heating leads to a reduction of free volumes. The heating treatment has a great influence on the magnetic susceptibilities. The treatment up to 600K improves soft magnetic properties: an χ increase was observed, from about 400 to almost 1000 for the samples of alloys without Pt, and from about 200 to 450 at maximum, for the Fe81Pt5Zr7Nb1Cu1B5. Further heating, at more elevated temperatures, leads to magnetic hardening of the samples. Curie temperatures, established from the location of Hopkinson’s maxima on the χ(T) curve are in very good agreement with those obtained from the data of specific magnetization, σ(T), measured in a field of 0.75T. As a critical parameter β was chosen to be equal 0.36 for these calculations, it confirmed that the alloys may be considered as ferromagnetic of Heisenberg type. Heating treatment resulted in decreasing of TC. These changes are within a range of several K.

12

Characterization of Three-Dimensional Printed Composite Scaffolds Prepared with Different Fabrication Methods

Szlązak K., Jaroszewicz J., Ostrowska B., Jaroszewicz T., Nabiałek M., Szota M., Swieszkowski W.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

645--650

EN

An optimal method for composites preparation as an input to rapid prototyping fabrication of scaffolds with potential application in osteochondral tissue engineering is still needed. Scaffolds in tissue engineering applications play a role of constructs providing appropriate mechanical support with defined porosity to assist regeneration of tissue. The aim of the presented study was to analyze the influence of composite fabrication methods on scaffolds mechanical properties. The evaluation was performed on polycaprolactone (PCL) with 5 wt% beta-tricalcium phosphate (TCP) scaffolds fabricated using fused deposition modeling (FDM). Three different methods of PCL-TCP composite preparation: solution casting, particles milling, extrusion and injection were used to provide material for scaffold fabrication. The obtained scaffolds were investigated by means of scanning electron microscope, x-ray micro computed tomography, thermal gravimetric analysis and static material testing machine. All of the scaffolds had the same geometry (cylinder, 4×6 mm) and fiber orientation (0/60/120°). There were some differences in the TCP distribution and formation of the ceramic agglomerates in the scaffolds. They depended on fabrication method. The use of composites prepared by solution casting method resulted in scaffolds with the best combination of compressive strength (5.7±0.2 MPa) and porosity (48.5±2.7 %), both within the range of trabecular bone.

13

Analysis of the Thermal and Magnetic Properties of Amorphous Fe61Co10Zr2.5Hf2.5Me2W2B20 (Where Me = Mo, Nb, Ni Or Y) Ribbons

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

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 2A

641--644

EN

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.

14

Ab Initio Study of Structure, Electronic and Magnetic Properties of YFe5 Phase Compound in the DFT Formalism

Gruszka K., Nabiałek M., Noga T

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

369--374

EN

Paper presents results of studies on structural, electronic and magnetic properties of YFe5 compound using density functional theory (DFT) approach. The GGA functional with ultrasoft pseudopotentials were used as implemented in Quantum Espresso software. The structure of YFe5 compound was examined in three different states namely nonmagnetic, antiferromagnetic and ferromagnetic. Also two antiferromagnetic configurations were considered. From the total energy viewpoint the most likely ferromagnetic configuration is favorable. In order to achieve mentioned aims we present projected density of states, electronic band structure and Löwdin population analysis studies results.

15

Zastosowanie żywicy epoksydowej Epidian 100 jako osnowy w kompozytach magnetycznych

Nabiałek M.

Przetwórstwo Tworzyw

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2015

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T. 21, Nr 2 (164)

139--142

PL

W pracy przedstawiono przykładowe wyniki badań właściwości magnetycznych oraz struktury kompozytów zbudowanych z żywicy epoksydowej Epidian 100 oraz amorficznego wypełniacza o właściwościach magnetycznych magnetycznie miękkich. Na podstawie analizy badań struktury wykonanych za pomocą dyfraktometru rentgenowskiego można stwierdzić, że badane kompozyty posiadały strukturę amorficzną, co w rezultacie jest potwierdzeniem amorficzności metalicznego wypełniacza. Podstawowe parametry opisujące materiał magnetycznie miękkie, tj. magnetyczna polaryzacja oraz pole koercji w badanych kompozytach zmieniają się w zależności od ilości diamagnetycznego lepiszcza lub frakcji stosowanego wypełniacza. W przypadku kompozytów magnetycznych już niewielka ilość diamagnetycznej żywicy epoksydowej Epidian 100 jest powodem gwałtownego pogorszenia parametrów magnetycznie miękkich.

EN

The paper presents an example of the results of the magnetic properties and structure of composites made of epoxy resin Epidian 100 and amorphous filler with magnetically soft magnetic properties. From the structure analysis made using the X-ray diffractometer can be concluded, that the examined composites had an amorphous structure, which in turn confirms the amorphous content of the filler metal. The basic parameters describing the soft magnetic material, i.e. magnetic polarization and the coercive field in the studied composites vary depending on the amount of binder or on diamagnetic fraction of the filler used. In the case of magnetic composites even a small quantity of Epidian 100 diamagnetic epoxy resin causes rapid deterioration of soft magnetic parameters.

16

Wpływ zawartości osnowy polimerowej na właściwości magnetyczne amorficznego proszku Fe60Co10Y8W1B20

Pietrusiewicz P., Nabiałek M.

Przetwórstwo Tworzyw

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2015

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T. 21, Nr 2 (164)

149--151

PL

W pracy przedstawiono wyniki badań kompozytów składających z ferromagnetyka Fe61Co10Y8W1B20 wykazującego miękkie właściwości magnetyczne związanego polimerem (Epidian 100) w proporcjach 2%, 3% i 4% wag. Przeprowadzono badania struktury wykorzystując dyfrakcje promieni rentgenowskich. Na podstawie tych badań wykazano że proces mielenia jak i utwardzania Epidianu w nie wpływa na strukturę badanych kompozytów powodując jej krystalizację. W kolejnym etapie przeprowadzono badania magnetyczne wykorzystując magnetometr wibracyjny (VSM). Pokazano, że można sterować właściwościami poprzez odpowiednie dobranie zawartości osnowy polimerowej.

EN

This paper presents results of research on the composites consisting of ferromagnetic Fe61Co10Y8W1B20 alloy exhibiting soft magnetic properties of bonded polymer (Epidian 100) in the proportion of 2%, 3% and 4% by weight. Structure study was carried out using X-ray diffraction. This research have shown that the process of grinding and Epidianu hardening does not affect the structure of the composites causing its crystallization. In a next step were studied by using a vibrating sample magnetometer (VSM). It is shown that the properties can be controlled through appropriate selection of the content of the polymer matrix.

17

Badania strukturalne i magnetyczne kompozytów wytworzonych na bazie stopu Fe67Co10Ni1W2B20 połączonego żywicą epoksydową

Bukowska A., Szota M., Nabiałek M., Pietrusiewicz P., Błoch K.

Przetwórstwo Tworzyw

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2015

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T. 21, Nr 2 (164)

94--97

PL

W pracy przedstawiono wyniki badań strukturalnych oraz magnetycznych kompozytów otrzymanych na bazie stopu o składzie chemicznym Fe67Co10Ni1W2B20 i żywicy epoksydowej. Badane próbki miały kształt walców oraz posiadały ten sam udział objętościowy żywicy epoksydowej (klej Epidian 100). Wytworzony stop o składzie chemicznym Fe67Co10Ni1W2B20 został niskoenergetycznie rozkruszony w moździerzu, a następnie poddany analizie sitowej i podzielony na trzy frakcje: 20-50 µm, 50-100 µm oraz 100-200 µm. Tak otrzymane proszki stopów zostały połączone z żywicą epoksydową. Określono wpływ wielkości cząstek proszku i osnowy na właściwości magnetyczne kompozytów.

EN

The paper presents the results of the structural and magnetic studies of composites obtained on the Basic of the alloy Fe67Co10Ni1W2B20 and epoxy resin (glue Epidian 100). The resulting alloy with chemical composition Fe67Co10Ni1W2B20 was low-energy crushed in a mortar, and then subjected to a sieve analysis and divided into three fractions: 20-50 microns, 50-100 microns and 100-200 microns. The thus obtained alloy powders were combined with an epoxy resin. Were identified: powder particle size and the magnetic properties of the matrix composites.

18

The microstructure and magnetic properties of Nd8.5Tb1.5Fe83Zr1B6 ribbons obtained at various cooling rates

Dośpiał M., Olszewski J., Nabiałek M., Pietrusiewicz P., Kaczmarzyk T.

Nukleonika

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2015

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Vol. 60, No. 1

15--18

EN

The paper presents results of microstructure and magnetic properties studies of Nd8.5Tb1.5Fe83Zr1B6 ribbons obtained by melt-spinning technique. The samples were produced using the rapid cooling of liquid alloy on the copper wheel, by applying three different linear velocities 20, 30, and 35 m/s. The microstructure of obtained ribbons was examined using X-ray diffractometry and Mössbauer spectroscopy. Magnetic measurements were performed using LakeShore vibrating sample magnetometer. The microstructure measurements were used for quantitative and qualitative analysis of phase composition. Basing on results of structure studies combined with magnetic measurements, the infl uence of phase composition on hysteresis loop behavior was described.

19

Effect of heat treatment on the shape of the hyperfine field induction distributions and magnetic properties of amorphous soft magnetic Fe62Co10Y8B20 alloy

Gruszka K. M., Nabiałek M., Błoch K., Olszewski J.

Nukleonika

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2015

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Vol. 60, No. 1

23--27

EN

Thermal treatment, undertaken at just below the crystallization temperature, has led to nanocrystallization and has had a signifi cant impact on the shape of the hyperfine field induction distributions of Fe62Co10Y8B20 alloy and on its soft magnetic properties. In the amorphous ferromagnetic alloys, it is possible to indirectly determine the effect of the structure stresses, resulting from the presence of structural defects, on the soft magnetic properties of these materials. It has been found that a change in the parameters associated with the presence of structural defects affects the shape of the hyperfi ne fi eld distributions of 57Fe.

20

The Magnetization Reversal Processes of Bulk (Nd, Y)‑(Fe, Co)‑B Alloy in the As-Quenched State

Dośpiał M., Nabiałek M., Szota M., Gondro J.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 3A

1587--1590

EN

The magnetization reversal processes of bulk Fe64Co5Nd6Y6B19 alloy in the as-quenched state have been investigated. From the analysis of the initial magnetization curve and differential susceptibility versus an internal magnetic field it was deduced, that the main mechanism of magnetization reversal process is the pinning of domain walls at the grain’s boundaries of the Nd2Fe14B phase. Basing on the dependence of the reversible magnetization component as a function of magnetic field it was found that reversible rotation of a magnetic moment vector and motion of domain walls in multi-domain grains result in high initial values of the reversible component. The presence of at least two maxima on differential susceptibility of irreversible magnetization component in function of magnetic field imply existence of few pinning sites of domain walls in Fe64Co5Nd6Y6B19 alloy. The dominant interactions between particles have been determined on the basis of the Wohlfarth dependence. Such a behavior of Wohlfarth’s plot implies that the dominant interaction between grains becomes short range exchange interactions.

PL

W pracy przedstawiono wyniki badań własności magnetycznych i mechanizmów przemagnesowania masywnego stopu Fe64Co5Nd6Y6B19 w stanie po zestaleniu. Z krzywych pierwotnego namagnesowania i ich podatności różnicowej określono, że głównym mechanizmem przemagnesowania jest kotwiczenie ścian domenowych. Na podstawie zależności składowych odwracalnych namagnesowania od pola magnetycznego stwierdzono, że procesy odwracalne takie jak obroty wektora namagnesowania oraz ruch ścian domenowych w wielodomenowych ziarnach mają znaczny wpływ na zmiany namagnesowania dla początkowych wartości pól magnetycznych. Obecność maksimów w zależności składowej nieodwracalnej podatności magnetycznej świadczy, że głównym mechanizmem przemagnesowania w badanych magnesach jest kotwiczenie ścian domenowych na licznych centrach kotwiczenia znajdujących się na granicach ziaren fazy Nd2Fe14B oraz na defektach strukturalnych. W celu określenia oddziaływań między ziarnami określono zależność Wohlfartha. Zależność ta nie jest spełniona dla badanego magnesu, świadczy to o istnieniu oddziaływania wymiennego między ziarnami magnesu.