Performance of soft magnetic cores based on the mixture of carbonyl iron and amorphous powders

Abstract

The mixture of carbonyl iron powders (CIP) with small particle size and amorphous powders (AP) with large particle size were employed for fabricating high performance soft magnetic cores. The extended discrete element method simulation (EDEM) showed that as the proportion of AP increases from 0 to 100 wt.%, the porosity of the core first decreases and then increases, reaching its lowest value at 70 wt.% AP. The micromagnetic simulations suggested that the enhanced static magnetic force between the powders with different sizes can promote the magnetic domain wall displacement. Experimental results confirmed that the highest compactness and lowest core loss of 408 kW/m³ at 50 mT and 100 kHz have been obtained at 70 wt.% AP, agreeing well with the simulation results. The permeability of the core increases with the AP content up to 30 wt.%, then decreases. The quality factor at 1 MHz monotonically decreases from 69.9 to 52.2 as the AP content increases. The core with 20 wt.% AP exhibits the highest crush strength due to the improved meshing ability between magnetic powders by densification. However, the addition of AP has negative effect on the DC bias performance, which needs further investigation.