Improved soft magnetic properties of Fe-based amorphous powder cores by softening phenolic resin shell

In this work, the minor alcohol was innovatively added to soften the hard phenolic-resin insulation shell which greatly improved the flowability of the core-shell (amorphous powder-insulating layer) particles during the molding process, effectively reducing damage to the coating and resulting in a higher density of powder cores (PC). Importantly, the permeability of the obtained PC was improved by 31 % at a softener content of 1.5 wt.%, and the corresponding core loss (50 mT, 100 kHz) was reduced by 45 % from 70.41 kW/m3 to 38.56 kW/m3. Moreover, the PC also exhibited improved DC bias and resistivity. Fundamentally, the high fluidity of the coreshell particles with alcohol softeners radically and effectively reduces the friction between the particles, thus improving the resistivity and reducing the air gaps in the PC, ultimately leading to lower eddy current losses and better magnetization.