Elevated temperature initial permeability study of Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 alloy

摘要

The effect of annealing temperature on the temperature dependence of initial permeability of Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9 alloy has been investigated. It was found that for the amorphous alloy consisting of a single phase a sharp Hopkinson peak appears and the Curie temperature value in as-quenched state was detected to be around 318℃, which can be increased by annealing at T_a ≤ 460℃. During the first stages of the crystallization to a nanophase structure, a smooth peak was observed on the μ_i-T curve. However, the nanostructured alloy containing a dual phase, which has excellent soft magnetic properties, showed a long tail character. In addition, at T_a = 600℃ two magnetic Curie transitions were found to be around 264 and 584℃, corresponding to residual amorphous and α-Fe(Si) nanocrystal phase, respectively. According to the change in the microstructure after annealing, the influences of the magnetic characteristic of residual amorphous matrix and the volume fraction of α-Fe(Si) nanocrystalline phase on the magnetic exchange coupling between nanosized grains and the temperature dependence of initial permeability were also discussed.