Permeability-Adjustable Nanocrystalline Flake Ribbon in Customized High-Frequency Magnetic Components

Fe-based nanocrystalline ribbon is an alternative to the ferrite for high-frequency magnetic cores due to its low hysteresis loss and high magnetic saturation. The drawback of the Fe-based nanocrystalline ribbon is its high conductivity. Crushing the homogenous ribbon to restructure a nanocrystalline flake ribbon (NFR) can reduce the conductivity while maintaining other superior magnetic properties of the noncrushed nanocrystalline ribbon. So far, several previous works have proven that the NFR can replace the ferrite in the dual active bridge and wireless power transfer system. However, seldom of these works mention the detailed mechanism of the NFR. In this article, the structure and manufacturing process of the NFR are introduced. The effect of the relative permeability and the crushing pattern on the magnetic properties of NFR has been quantitatively reported. A dual-permeability core formed by two types of NFR has been demonstrated for an inductor. Comparison has been made to inductors using the ferrite core (N27, N87, DMR44) in a similar size. Experiment results show that the dual-permeability NFR core has a lower core loss and higher magnetic saturation than the ferrite counterparts at frequencies from 100 to 300 kHz.