The amorphous ribbon Fe_73.5Si_13.5B₉Nb ₃Ag₁ has been prepared by rapid cooling on a single copper wheel. The DSC curves show the very sharp peak at 593-617 °C depending on the heating rate from 10 °C/min to 50 °C/min, which is higher than that for pure Finemet (540-572 °C, respectively). The crystallization activation energy of α-Fe(Si) phase has been determined and shown to be E=4.09eV, higher than that of pure Finemet (E=3.25eV). After annealing at 550 °C for 10 min, the crystallization volume fraction of α-Fe(Si) phase reaches the value of 78.4% with average grain size of 32 nm. The M(T) measurement along cooling cycle exhibits clearly two-step curve corresponding to the multiphase structure of the ribbon. The annealing of ribbon leads to the occurrence of nanocomposite state and improvement of soft magnetic properties of the material. © 2004 Elsevier B.V. All rights reserved.

Chau N., Hoa N.Q., Luong N.H.

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Từ khóa : Amorphous materials; Cooling; Copper; Crystallization; Grain size and shape; Heating; Magnetic anisotropy; Magnetic permeability; Magnetostriction; Nanostructured materials; Reaction kinetics; Silver; Substitution reactions; Volume fraction; X ray diffraction analysis; Amosphous structures; Crystallization kinetics; Fluctuation length; Grain diameter; Heating rates; Iron alloys