Effect of Binder Content on Structure and Magnetic Properties of Fe-Si Powder Cores

The structure and magnetic properties of Fe- 3.5 wt.% Si (Fe-Si) powder core with different binder contents were investigated. A similar structure of Fe-Si powder cores with mainly A2 phase was confirmed regardless of the binder content. As the binder content increased, both the saturation magnetization and the initial real part of permeability decreased with the density, which was related by the filling degree of the core. The lowest core loss
$\boldsymbol{P}_{\mathbf{cv}}$
was observed in the powder core with a binder content of 1.0 wt.%. These results suggest that a higher binder content can improve the resistivity of the powder core and insulate the particles, resulting in the lower eddy current loss and, consequently, lower core loss in the high frequency range. Therefore, Fe-Si powder core can be considered for applications in higher frequency range, which were not explored before.