Soft Magnetic Properties of Magnetic Cores Assembled With a High $B_{s}$ Fe-Based Nanocrystalline Alloy

Soft magnetic properties of magnetic cores assembled with Fe_81.8Cu_1.0Mo_0.2Si₄B₁₄ nanocrystalline alloy ribbon are discussed. The nanocrystalline alloy ribbon was cast in an amorphous phase by a melt quenching method, and a nanocrystalline phase was obtained by high-heating rate annealing. A medium-size toroidal core assembled with this nanocrystalline alloy ribbon exhibits magnetic flux density <inline-formula> <tex-math notation="LaTeX">$B_{{{800}}}$ </tex-math></inline-formula> at 800 A/m of 1.74 T, core loss <inline-formula> <tex-math notation="LaTeX">$P_{{{16/50}}}$ </tex-math></inline-formula> at 50 Hz, and at 1.5 T of 0.29 W/kg. A racetrack-shaped core, which includes curved and straight sections in the same core, exhibits core losses at 1.0 T and at 400 Hz and 1 kHz of 1.5 and 5 W/kg, respectively. These core losses are as low as those of Fe-based amorphous alloys. A medium-size toroidal core assembled with this nanocrystalline alloy ribbon, secondarily annealed under a perpendicular magnetic field, exhibits core loss <inline-formula> <tex-math notation="LaTeX">$P_{{{2/10k}}}$ </tex-math></inline-formula> at 0.2 T and at 10 kHz of 2 W/kg. This value of core loss is one of the lowest values for the metallic magnetic cores, which have a saturation induction <inline-formula> <tex-math notation="LaTeX">$B_{s}$ </tex-math></inline-formula> higher than 1.5 T. A core assembled with this material can be used in several applications from low to medium frequency ranges. Since this material exhibits a higher <inline-formula> <tex-math notation="LaTeX">$B_{s}$ </tex-math></inline-formula> and one half of the saturation magnetostriction <inline-formula> <tex-math notation="LaTeX">$\lambda \text{s}$ </tex-math></inline-formula> of Fe-based amorphous alloys with comparable core losses, the most possible applications are in such applications as distribution transformers and inductors in power electronics.