Abstract
For the production of nanocrystalline soft-magnetic compacts with high saturation magnetization, we investigated the densification behavior of amorphous and nanocrystalline Fe86Zr7B6Cu1 (at.%) powders using a hot-pressing machine, and the magnetic properties of the compacts. The density of the compacts produced from the nanocrystalline powder was 90.4 %. However, nanocrystalline compacts with a high density of 99.9 % were obtained by hot pressing the amorphous powder under 1.5 GPa and 853 K. We constructed the densification map of the amorphous and nanocrystalline powders. The pressure required to produce dense compacts, which was estimated from this map, is 3.0 GPa for the production of amorphous compacts, and 4.4 GPa for the consolidation of the nanocrystalline powder into nanocrystalline compacts, and only 1.5 GPa for the direct consolidation of the amorphous powder into nanocrystalline compacts. The consolidation of the amorphous powder through the crystallization is the most appropriate method for the production of dense nanocrystalline compacts. The dense nanocrystalline compacts exhibited good soft-magnetic properties which were superior to those of Fe-based amorphous compacts, in addition to a high saturation magnetization of 1.56 T. The coercive force, effective permeability at 1 kHz and 0.8 A/m, and core loss at 10 kHz and 0.1 T were 33 A/m, 1300 and 37 W/kg, respectively.
