Fe78Si9B13 amorphous powder core with improved magnetic properties

The effects of pre-annealing treatments on the soft magnetic properties of the corresponding Fe78Si9B13 amorphous powder cores were investigated. The amorphous powder cores prepared from pre-annealed powder have better soft magnetic properties compared with unpretreated powder core in the as-cast state. The result shows that the powder after pre-annealing in a magnetic field presents a regular domain structure and the soft magnetic properties of the corresponding powder cores are greatly improved. As the result, the magnetic-field annealed powder core has the highest effective permeability (μe) of 37, which is 23 % higher than the as-cast one and 7 % than only vacuum-annealed one. The total core loss (Pcv) for the core annealed in magnetic field is only 141 W/kg (100 kHz, 50 mT) and as low as 36 % of the Pcv for the powder core in the as-cast state. The one annealed in magnetic field also exhibits the best DC bias properties of 92 %. This work provides a novel approach to realizing low Pcv and high μe for Fe78Si9B13 powder cores and also validates the application prospect of powder cores in the work condition of different ripple currents, different loads and a wide frequency (f) range (10 kHz–10 MHz).