Permeability of soft magnetic composites from flakes of nanocrystalline ribbon

The permeability of powder cores is usually modeled using a nonmagnetic grain boundary model (NMGB), which is not satisfying in the case of composites based on ground nanocrystalline ribbon, especially for particles larger than several 100 mum. An improvement of the NMGB model is proposed where both in plane and perpendicular reluctances are taken into account. This model is consistant with our experimental results as well as other authors' results in a very large range of packing fractions (30%-92%) and particle sizes (80-1000 mum).