Publication: Nanocrystallization in Fe81B13.5Si3.5C2 amorphous magnetic ribbons
Issued Date
2008-02-01
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03048853
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2-s2.0-35448942802
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Mahidol University
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SCOPUS
Bibliographic Citation
Journal of Magnetism and Magnetic Materials. Vol.320, No.3-4 (2008), 81-90
Suggested Citation
W. Pon-On, P. Winotai Nanocrystallization in Fe81B13.5Si3.5C2 amorphous magnetic ribbons. Journal of Magnetism and Magnetic Materials. Vol.320, No.3-4 (2008), 81-90. doi:10.1016/j.jmmm.2006.04.039 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/19896
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Title
Nanocrystallization in Fe81B13.5Si3.5C2 amorphous magnetic ribbons
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Abstract
Nanocrystallization in amorphous ribbons Fe81B13.5Si3.5C2was fully investigated by using X-ray diffractometer (XRD), Mössbauer spectroscopy (MS), differential scanning calorimeter (DSC), and vibrating sample magnetometer (VSM) after annealing in the temperature range 400-600 °C for 2 h under argon atmosphere. DSC results show two exothermic peaks at 495 and 525 °C which clearly represent two crystallization temperatures corresponding to activation energies of 385 and 366 kJ/mol, respectively. Heat treatments of the ribbon below the first crystallization temperature yielded nanograins of the soft magnetic phase of α-Fe(Si) embedded in the remaining amorphous matrix. Mössbauer parameters originating from nanocrystalline phases of α-Fe(Si), t-Fe2B, and t-Fe3B (t for tetragonal), could be evaluated after annealing at 500 °C for 2 h. The presence of nanocrystalline phases was also confirmed by XRD patterns. The amorphous ribbon completely crystallizes into α-Fe, α-Fe(Si), t-Fe2B, t-Fe3B, and Fe3C (orthorhombic) after 600 °C. The coercivity rapidly increases with the annealing temperature with the exception of the ribbon annealed at 425 °C which yields only the soft α-Fe(Si) nanocrystalline phase. The coercivity of ribbon increases to 6.25 and 10.56 Oe after 2-h annealing at 425 and 475 °C, respectively, compared to that of as-cast sample, 5.29 Oe. However, it increases sharply to 61.11 and 74.99 Oe after heat treatments at 525 and 575 °C, respectively. Meanwhile, Mrincreases sharply from as-cast value 3.26 to 43.64 emu/g after 2-h annealing at 575 °C. However, Msshows only slight increase from the as-cast value of 165.53 to 207.99 emu/g after 2 h annealing at 575 °C. © 2007.