Magnetic Properties of Fe-Based Amorphous Powder Cores With High Magnetic Flux Density

Fe-81(Si0.3B0.7)(17)C-2 amorphous powder cores with glass binder were fabricated by compact-pressing techniques, and the relation between magnetic properties and powder particle sizes was evaluated. The Fe-81(Si0.3B0.7)(17)C-2 powder core exhibited superior magnetic properties compared with our previously developed (Fe0.97Cr0.03)(76)(Si0.5B0.5)(22)C-2 powder core. The magnetic flux density Bm of the core made of Fe-81 system powders at 20 000 A/m was about 29% higher than that of Fe-76 system core. The core loss decreased with decreasing particle sizes. For the core made of powders with mean particle size of 22 mu m below 45 mu m in diameter, the loss at 100 kHz for Bm = 0.1 T was 520 kW/m(3). This value was comparable to that of Fe-76 system powder core with a lower flux density. In addition, fairly superior characteristics of permeability under dc bias field were also attained. The values of Fe-81 system core was about 10% higher than that of Fe-76 system almost over the entire range measured.