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.
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