INFLUENCE OF QUENCHING RATE ON THE STRUCTURE, MORPHOLOGY, AND HYPERFINE PARAMETERS OF AMORPHOUS RIBBONS

Narges Amini – Július Dekan – Milan Pavúk – Safdar Habibi – Marcel Miglierini

   In this work, an amorphous alloy with the nominal composition of Fe₇₈Si₉B₁₃ was produced by a melt spinning method. Using different velocities of a quenching cooper wheel enabled us to study the influence of quenching rate upon the structural characteristics of the resulting ribbons. Structural features of the samples were checked by Mössbauer spectroscopy and X-ray diffraction. The latter performed in a grazing angle geometry enabled us to explore both sides of the as-quenched ribbons. The onset of crystallization was estimated by differential scanning calorimetry (DSC) measurements. Surface features of the ribbons were examined by Scanning Electron Microscopy (SEM). In order to observe structural relaxation phenomena the samples were annealed below the onset of crystallization at 450 C for 1 hour in Ar protective atmosphere. Even though the annealed ribbons are still amorphous relevant changes were observed in their hyperfine parameters as derived from Mössbauer spectrometry.

Keywords: amorphous alloys, XRD, DSC, SEM, Mössbauer spectrometry, heat treatment

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