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Abstract

The five-layer Aurivillius type structures with the general chemical formula Bi5Fe2-xMnxTi3O18, where x = 0, 0.6, 1.2 have been synthesized and tested. The SEM studies showed a significant increase in grain size in the manganese-modified Aurivillius type ceramic material (for x = 1.2). The increase in the amount of manganese ions (Mn3+) affects the decrease in the temperature at which the relaxation processes take place. Namely from 525 K (1 kHz) and 725 K (1 MHz) for BFT sample (x = 0) to 355 K (1 kHz) and 565 K (1 MHz) for BFM12T sample (x = 1.2). Using the Arrhenius’s law and the Vogel-Fulcher’s relationship the activation energy (Ea) and the relaxation time have been calculated. The value of Ea increases with the increase of the Mn amount from 0.737 eV (for x = 0) to 0.915 eV (for x = 1.2).
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Abstract

Multiferroic composites are very promising materials because of their applicability because the magnetoelectric effect occurs in them. The subject of the study were two multiferroic ceramic composites: leaded obtained from powder of the composition PbFe0.5Nb0.5O3 and ferrite powder of the composition Ni0.64Zn0.36Fe2O4 and unleaded which was obtained from the powder of the composition BaFe0.5Nb0.5O3 and the same ferrite powder Ni0.64Zn0.36Fe2O4. For the both multiferroic materials the following studies were conducted: SEM, BSE, EDS, XRD and the temperature dependence of dielectric constant ε(T). Using the previously developed method of calculating the magnetoelectric coupling factor (g), based on dielectric measurements, the magnitude of the magnetoelectric effect in the multiferroic composites was determined.
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Abstract

The paper presents the study results of laser modification of Vanadis-6 steel after diffusion boronized. The influence of laser beam fluence on selected properties was investigated. Diffusion boronizing lead to formation the FeB and Fe2B iron borides. After laser modification the layers were consisted of: remelted zone, heat affected zone and substrate. It was found that increase of laser beam fluence have influence on increase in dimensions of laser tracks. In the thicker remelting zone, the primary dendrites and boron eutectics were detected. In the thinner remelting zone the primary carbo-borides and eutectics were observed. In obtained layers the FeB, Fe2B, Fe3B0.7C0.3 and Cr2B phases were detected. Laser remelting process caused obtained the mild microhardness gradient from the surface to the substrate. In the remelted zone was in the range from 1800 HV0.1 to 1000 HV0.1. It was found that the laser beam fluence equal to 12.7 J/mm2 was most favorable. Using this value, microhardness was relatively high and homogeneous.
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