Fe-based amorphous powder cores with low core loss and improvement of permeability

Fe-based amorphous powder cores of Fe-Si-B-Cr-C magnetic powder and phenolic binder were fabricated, and the effects of annealing and compaction pressure on the soft magnetic properties and core loss were investigated. The formation of Fe-B and alpha-Fe (Si) phases was confirmed at the annealing temperature above 773 K. The density gradually increased from 5.3 to 5.5 g/cm(3) as annealing temperature increased, resulting in the saturation magnetization 4 pi Ms increased to 1.0 T at 773 K. The effect of compaction pressure was studied by using samples annealed at 723 K. Both the density and 4 pi Ms enhanced with compaction pressure from 980 to 1960 MPa. The real part of permeability mu' remained constant for the frequency up to 2 MHz. The initial value of mu' increased from 25 to 38 with compaction pressure. Consequently, at Bm of 50 mT and frequency of 100 kHz, the considerably low core loss of 67 kW/m(3) was obtained. The low core loss and moderately high permeability of Fe-Si-B-Cr-C amorphous powder core across a wide frequency range indicate its potential for application in high frequency electronic components.