LAUSR

Abstract We developed nanocrystalline powders with high Fe contents through methodological and compositional innovations. The Fe-Cr-Cu-Si-B-Sn powders exhibit high Bs of 1.55 T–1.60 T and core losses of 4800–8000 kW/m3 at 2 MHz under 30 mT, P0.2/3M. The Cu clusters provide a high number density of nucleation sites, leading to the formation of powders with nanocrystalline structures. It is found that high number density of Cu clusters are realized by distribution of sub-nanometer Sn clusters, especially near the surface. The addition of Sn enables the maintenance of a stable supply of nucleation sites regardless of powder diameters i.e., a wide variety of quenching rates is accepted.