New High-Bs Fe-Based Nanocrystalline Soft Magnetic Alloys

The magnetic properties and microstructures of newly developed Fe–Cu–B and Fe–Cu–Si–B alloys produced by melt-spinning have been studied. The annealed alloys consist of nanoscale grains. The annealed alloys show a high-saturation magnetic flux density Bs of more than 1.8 T and excellent soft magnetic properties such as a low core loss of about 0.3 W/kg at 50 Hz and 1.5 T (P15/50). For the present alloys, the addition of Cu is effective for the formation of nanoscale grains and the improvement of the soft magnetic properties.