Fabrication of an Fe80.5Si7.5B6Nb5Cu 
Amorphous-Nanocrystalline Powder Core with Outstanding Soft Magnetic Properties
In this study, the melt spinning method was used to develop Fe80.5Si7.5B6Nb5Cu amorphous ribbons in the first step. Then, the Fe80.5Si7.5B6Nb5Cu amorphous-nanocrystalline core with a compact microstructure was obtained by multiple processes. The main properties of the magnetic powder core, such as micromorphology, thermal behavior, permeability, power loss and quality factor, have been analyzed. The obtained results show that an Fe80.5Si7.5B6Nb5Cu amorphous-nanocrystalline duplex core has high permeability (54.8–57), is relatively stable at different frequencies and magnetic fields, and the maximum power loss is only 313 W/kg; furthermore, it has a good quality factor.