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

Fe₈₁(Si_0.3B_0.7)₁₇C₂ 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 Fe₈₁ (Si_0.3B_0.7)₁₇C₂ powder core exhibited superior magnetic properties compared with our previously developed (Fe_0.97Cr_0.03)₇₆ (Si_0.5 B_0.5 )₂₂C₂ powder core. The magnetic flux density Bm of the core made of Fe₈₁ system powders at 20 000 A/m was about 29% higher than that of Fe₇₆ system core. The core loss decreased with decreasing particle sizes. For the core made of powders with mean particle size of 22 mum below 45 mum in diameter, the loss at 100 kHz for Bm = 0.1 T was 520 kW/m³. This value was comparable to that of Fe₇₆ 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 Fe₈₁ system core was about 10% higher than that of Fe ₇₆ system almost over the entire range measured.