Magnetic Properties of Amorphous Fe-Si-B Powder Cores Mixed with Pure Iron Powder

Amorphous Fe-Si-B alloy was prepared by melt-spinning, and then the ribbons were pulverized and ball-milled to make the amorphous powder of similar to 25 mu m in size. Subsequently those were mixed with pure iron powders with an average particle size of 3 mu m, and 1.5 wt% water glass diluted by distilled water at the ratio of 1 : 2. The powder mixtures were cold compacted at 650 MPa in toroid die, and heat treated at 430-440 degrees C under a nitrogen atmosphere for 1 h and 30 min, respectively. The soft magnetic properties of powder core were investigated using a B-H analyzer and a flux meter at the frequency range of similar to 100 kHz. The microstructure was observed using scanning electron microscope (SEM), and the density of the core was measured using the principle of Archimedes. Based on the experimental results, the amorphous powder mixed with pure iron powder showed the improved powder compactability, which resulted in the increased permeability and the reduced core loss. (C) 2012 The Japan Society of Applied Physics