Hyperfine interactions in nanocrystallized NANOPERM-type metallic glass containing Mo

0463846 - ÚACH 2017 RIV NL eng J - Článek v odborném periodiku
Cesnek, M. - Kubániová, D. - Kohout, J. - Kříšťan, P. - Štěpánková, H. - Závěta, K. - Lančok, Adriana - Štefánik, M. - Miglierini, M.
Hyperfine interactions in nanocrystallized NANOPERM-type metallic glass containing Mo.
Hyperfine Interactions. Roč. 237, č. 1 (2016), č. článku 132. ISSN 0304-3843.
[International Conference on Hyperfine interactions and their applications (HYPERFINE 2016). Leuven, 03.07.2016-08.07.2016]
Grant CEP: GA ČR(CZ) GA14-12449S
Institucionální podpora: RVO:61388980
Klíčová slova: Hyperfine interactions * Metallic glass * Mössbauer spectrometry * Nuclear magnetic resonance
Obor OECD: Inorganic and nuclear chemistry

NANOPERM-type alloy with chemical composition Fe76Mo8CuB15 was studied by combination of 57Fe Mössbauer spectroscopy and 57Fe(10B, 11B) nuclear magnetic resonance in order to determine distribution of hyperfine magnetic fields and evolution of relative concentration of Fe-containing crystalline phases within the surface layer and the volume of the nanocrystallized ribbons with annealing temperature. Differential scanning calorimetry revealed two crystallization stages at Tx1 ∼ 510 ∘C and Tx2 ∼ 640 ∘C, connected to precipitation of α-Fe and Fe(Mo,B) nanocrystals, respectively. The amorphous and partially crystalline state was obtained by annealing at several temperatures in the range 510-650 ∘C. The combination of conversion electron (CEMS) and transmission Mössbauer spectrometry (TMS) showed that annealing induces crystallization starting from both surfaces of the ribbons. For the as-quenched sample, scanning electron microscopy (SEM) and CEMS revealed significant differences in the"air" and "wheel" sides of the ribbons, crystallites were preferentially formed at the latter. While SEM micrographs of annealed samples showed various mean diameters of the crystals at opposite sides of the ribbons, the amounts of crystalline volume derived from the CEMS spectra approximately equaled. Mössbauer spectra of annealed samples contained narrow sextet ascribed to crystalline α-Fe phase, three sextets with distribution of hyperfine field assigned to the interface regions of the nanocrystals and the contribution of the amorphous phases. In-field TMS performed at 4.2 K with magnetic moments aligned by external magnetic field enabled to properly determine in particular the contribution of the amorphous phases in the samples. Resulting distributions of the hyperfine fields were compared with 57Fe(10B, 11B) nuclear magnetic resonance (NMR) spectra.
Trvalý link: http://hdl.handle.net/11104/0262943