Magnetic properties of Fe_78.4Si_9.5B₉Cu_0.6Nb_2.5 nanocrystalline alloy powder cores

Abstract

The microstructure and morphology of nanocrystalline Fe_78.4Si_9.5B₉Cu_0.6Nb_2.5 alloy powders prepared by ball milling technique were characterized by X-ray diffraction and scanning electron microscopy studies. The effective permeability (μ_e), quality factor (Q), DC bias property, and core losses of the corresponding powder cores were tested using low capacitance resonator meter and B–H analyzer in the range of 1–1000 kHz. The results show that the relative density and compression strength of the powder cores increased with increasing particle size. Powder cores from large size particles (150–300 μm) were found to exhibit higher μ_e and core loss, but lower Q level when compared to samples of small size ones (5–40 μm). Moreover, the μ_e of powder cores with large particles reached a peak value with the addition of 2 wt% glass binder. The Q value was also found to be proportional to the binder content except 10 wt%, while its peak position was shifted toward higher frequency.