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EN
In this paper, the results of the complex examination of the 42CrMo4 steel samples are presented. The samples were taken from the metallurgical forging prepared for the production of the wind turbine main shaft. The samples underwent Mössbauer spectroscopic analysis, as well as the measurement of its mechanical characteristics such as hardness and strength are analysed. Conversion electron Mössbauer spectrometry confirmed phase purity and isotropy of the investigated 42CrMo4 steel. The method provided accurate results, proving Mössbauer spectrometry to be an effective tool for the wind turbine main shaft analysis.
EN
Several samples of dusts from steel and coke plants (collected mostly with electro filters) were subjected to the investigation of content of mineral phases in their particles. Additionally, sample of bog iron ore and metallurgical slurry was studied. Next, the magnetic susceptibility of all the samples was determined, and investigations of iron-containing phases were performed using transmission Mössbauer spectrometry. The values of mass-specific magnetic susceptibility  varied in a wide range: from 59 to above 7000 × 10−8 m3kg−1. The low values are determined for bog iron ore, metallurgical slurry, and coke dusts. The extremely high  was obtained for metallurgical dusts. The Mössbauer spectra and X-ray diffraction patterns point to the presence of the following phases containing iron: hematite and oxidized magnetite (in coke and metallurgical dusts as well as metallurgical slurry), traces of magnetite fi ne grains fraction (in metallurgical dusts), amorphous glassy silicates with paramagnetic Fe3+ and Fe2+ ions, traces of pyrrhotite (in coke dusts), α-Fe and nonstoichiometric wüstite (in metallurgical slurry), as well as ferrihydrite nanoparticles (in bog iron ore). For individual samples of metallurgical dusts, the relative contributions of Fe2+/3+ ions in octahedral B sites and Fe2+ ions in tetrahedral A sites in magnetite spinel structure differs considerably.
EN
The investigations of iron-containing phases existing in fly ashes were performed using transmission Mössbauer spectrometry. The examined samples of fly ashes were collected from different coal combustion systems, that is, stoker-fired boiler in municipal heating plant and pulverized coal boiler in power plant. Several phases are identifi ed in the samples: iron oxides, paramagnetic aluminosilicate glass with Fe3+ ions and Al2O4- -type spinel with Fe2+ ions. It was pointed out that proportions of contents of phases strongly depend not only on the combustion temperature but also on the way of ash collection.
EN
This work reports results from comparative Mossbauer studies of as-deposited and annealed Fe100.xGax (10 less - than or equal to x less - than or equal to 35) high magnetostrictive thin films of constant thickness (50 plus or minus 2 nm). Films were grown on Si(100) substrates using a co-sputtering and evaporation chamber where Fe has been sputtered and Ga was evaporated. During growth of films, a magnetic field of 65 kA/m has been applied in the plane of the film. Annealed films have been obtained by heating in vacuum for 1 h at 350 centigrade without magnetic field. After annealing, the saturation field of the Fe-Ga films has been significantly reduced. By means of the 57Fe CEMS technique the contributions from several phases have been found: Fe-Ga A2 (bcc), traces of DO3 phase, a gallium-rich disordered phase and iron oxides (both geothite and magnetite). For the sample with x = 26.5 the heat treatment reduces the DO3 phase content whereas for the film with x = 16.4 the opposite tendency has been observed. Mossbauer results were compared with XRD and MOKE findings.
5
Content available remote Pseudodipolar model of surface magnetostriction for thin layers with roughness
EN
An effective magnetostriction model for monocrystalline thin films of cubic structure has been presented. The film roughness was simulated by cubicoidal steps on surface repeated in the plane with a constant period. In order to describe a magnetoelastic energy, a pseudodipolar spin–spin interaction was considered. Lattice summations of strain dependent energy contribution were performed symbolically. A significant difference of magnetoelastic energy compared with the film interior was observed only in the first atomic layer at the surface. An effective pseudodipolar magnetostriction constant λ eff for rough film was determined by estimating the volume of surface region and considering the magnetostriction data for bulk material. Thickness dependence of λ eff for bcc Fe film has been presented and compared with magnetic dipolar contribution.
EN
Thermomagnetic curves obtained with Mössbauer spectrometry for two-phase nanocrystalline alloys have been analyzed theoretically. The main goal was to understand a slope jump in the temperature dependence of the hyperfine field for crystalline phase of higher Curie temperature at the Curie point of the amorphous phase. We propose a simple model introducing an effective exchange integral for one phase depending on mean spin value in the other phase. We also consider a strong spin polarization of the amorphous phase by penetrating field originating from nanocrystallites. Results of numerical calculations within the mean field approximation (MFA) reproduce qualitatively the experimental curves for nanocrystalline FINEMET and Fe-Nb-B alloys.
PL
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