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Microstructural characterisation of sintered soft magnetic nanocomposite materials

Konieczny J., Czaja I., Dobrzański L.A.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 61, nr 2

202--209

EN

Purpose:The main aim of this work is to investigate microstructure of of sintered soft magnetic nanocomposite materials produced by sintering axially on one side in the ambient atmosphere. Design/methodology/approach: Microstructure observations of 20 mm diameter sintered roller by light microscopy OLYMPUS, scanning electron microscopy OPTON DSM-940 and ZEISS SUPRA 35, and transmission electron microscopy JEOL 3010. The X-ray tests were realized with the use of the XRD 7 SEIFERT-FPM diffractometer equipped with the lamp of the cobalt anode of 35 kV voltage and 30 mA filament current was used. The nanocrystalline ferromagnetic powders were manufactured by high-energy ball milling (8000 SPEX CertiPrep Mixer/Mill) of metallic glasses ribbons in as state. The hot pressing process was made on machine “Degussa”. Findings: The analysis of the results enabled determination of the hot pressing parameters on structure of obtained stampings. This is typical of an dispersion strengthened case. Research limitations/implications: For the sintered roller obtained from metallic Co-based amorphous ribbons, further mechanical and magnetic examinations are planed. Practical implications: Conducted research shows that applied technology of sintered roller production allows to obtain good microstructural characteristics. Structure analysis of die stampings of powdered amorphous metallic ribbons is helpful to prepare this material by laboratory methods. Feature an alternative to commercial alloys and composite materials are the amorphous and nanocrystalline metal amorphous ribbons obtained by melt spinning technique and make it possible to obtain the new composite materials with best magnetic properties, which dimensions and shape can be freely formed. Originality/value: The paper presents influence of hot pressing parameters process of metallic powdered ribbons Co77Si11.5B11.5 on structure of obtained die stampings.

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Structure and magnetic properties of powder HITPERM material

Konieczny J., Dobrzański L. A., Frąckowiak J. E.

Archives of Materials Science and Engineering

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2007

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Vol. 28, nr 3

156-164

EN

Purpose: The aim of the work is to investigate the structure and magnetic properties of the cobalt based HITPERM amorphous alloy Co68Fe4Mo1Si13.5B13.5 subjected high-energy ball milling and to the isothermal annealing to a combination of these two technologies. Design/methodology/approach: The nanocrystalline ferromagnetic powders were manufactured by highenergy ball milling of metallic glasses ribbons in as state. Using the HFQS program the distributions of the magnetic hyperfine P(H) fields were determined for spectra smoothed in this way, employing the Hesse-Rübartsch method. Observations of the structure of powders were made on the OPTON DSM-940 scanning electron microscope. The diffraction examinations and examinations of thin foils were made on the JEOL JEM 200CX transmission electron microscope equipped in equipped with the EDS LINK ISIS X- ray energy dispersive spectrometer made by Oxford. Graphical analyses of the obtained X-ray diffraction patterns, as well as of the HC=f(TA) relationship were made using the MICROCAL ORIGIN 6.0 program. Findings: The analysis of the structure and magnetic properties test results of the HITPERM powders alloy Co68Fe4Mo1Si13.5B13.5 obtained in the high-energy ball of milling process proved that the process causes significant decrease in the magnetic properties. The magnetic properties of this material and structure and may be improved by means of a proper choice of parameters of this process as well as the final thermal treatment. Research limitations/implications: For the soft magnetic powder material, further magnetical, composition examinations and structure are planed. Practical implications: Feature an alternative to solid alloys are the amorphous and nanocrystalline metal powders obtained by milling of metallic glasses and make it possible to obtain the ferromagnetic nanocomposites, whose dimensions and shape can be freely formed. Originality/value: The paper presents results of influence of parameters of the high-energy ball milling process on magnetic properties and structure of soft magnetic powder HITPERM alloy obtained in this technique. The paper compares magnetic properties and structure of the HITPERM alloy obtained in high-energy ball milling process, melt spinning technique and in a combination of these two technologies.

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Structure and properties of the powder obtained from the amorphous ribbon

Konieczny J., Dobrzański L. A., Frąckowiak J. E.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

143--146

EN

Purpose: The aim of the work is to investigate the magnetic properties of the cobalt based Co68Fe4Mo 1Si13.5 B13.5 amorphous alloy subjected to the isothermal annealing, high-energy milling and to a combination of these two technologies. Design/methodology/approach: The powder test piece obtained from the input amorphous ribbon in high-energy ball milling. Distributions of the magnetic hyperfine P(H) fields were determined for spectra smoothed in this way, by using the HFQS program, employing the Hesse-Rübartsch method. The diffraction examinations and examinations of thin foils were made on the JEOL JEM 200CX transmission electron microscope. Observations of the structure of powders were made on the Opton DSM-940 scanning electron microscope. Findings: The analysis of the magnetic properties test results of the of the Co68Fe4Mo 1Si13.5B13.5 powders obtained in the high-energy ball of milling process proved that the process causes significant decrease in the magnetic properties. The structure and magnetic properties of this material may be improved by means of a proper choice of parameters of this process as well as the final thermal treatment. Research limitations/implications: For the powders, further magnetical, structure and composition examinations are planed. Practical implications: The amorphous and nanocrystalline metal powders obtained by milling of metallic glasses feature an alternative to solid alloys and make it possible to obtain the ferromagnetic nanocomposites, whose shape and dimensions can be freely formed. Originality/value: The paper presents influence of parameters of the high-energy ball milling process on structure and magnetic properties of soft magnetic powder materials obtained in this technique. The paper compares structure and magnetic properties of the Co 68Fe4Mo 1Si13.5B13.5 alloy obtained in high-energy ball milling process and melt spinning technique.

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Study of mechanically activated V-Cr oxides for catalytic applications

Wieczorek-Ciurowa K., Gomułczak A., Rakoczy J., Gamrat K., Stoch J., Sawłowicz Z.

Polish Journal of Applied Chemistry

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2005

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Vol. 49, nr 4

253-262

EN

The influence of mechanical activation by a high-energy ball milling on the physical, chemical and catalytic performance of V2O5, Cr2O3 and their mixture (molar ratio 1:10) was investigated. The comparison of samples activated in dry and wet conditions with non-activated samples is presented. The milling process caused an increase in acidity of samples due to a higher concentration of vanadium observed on the surface of mechanically activated samples.

PL

Badano wpływ mechanicznej aktywacji realizowanej poprzez wysokoenergetyczne mielenie kulowe na fizyczne, chemiczne i katalityczne właściwości V2O5, Cr2O3 i mieszanin tlenków o stosunku molowym V:Cr = 1:10. Przedstawiono porównanie efektów aktywacji prowadzonej na sucho i na mokro z wynikami dla próbek nie aktywowanych. Proces mielenia spowodował wzrost kwasowości z powodu podwyższonej koncentracji wanadu obserwowanej na powierzchni próbek.