Magnetic properties of FeCuNbSiB nanocrystalline alloy powder cores using ball-milled powder

Cold-pressed nanocrystalline powder cores were fabricated using powders of nanocrystalline ribbons which were ball milled for short time. Their magnetic properties at high frequency were measured. The powder size ranges from 20 to 850 mum and the contents of the glass binder are between 1 and 8 wt %. For cores composed of large particles of 300-850 mum with 5 wt % glass binder, we obtained a stable permeability of 100 up to 800 kHz, a maximum level 31 of quality factor at frequency of 50 kHz, and 320 mW/cm3 core loss at f=50 kHz and B-m=0.1 T. This is mainly due to the good soft magnetic properties of the powders and the higher insulation of powder cores which cause low eddy current losses. (C) 2003 American Institute of Physics.