Mechanically strong nanocrystalline Fe-Si-B-P-Cu soft magnetic powder cores utilizing magnetic metallic glass as a binder

We report on the fabrication and properties of soft magnetic powder cores with superior mechanical strength as well as low core loss (W). Development of such cores is important for applications in automobiles/devices operating in motion. High saturation magnetic flux density (B_s) Fe-Si-B-P-Cu powder was sintered with Fe₅₅C₁₀B₅P₁₀Ni₁₅Mo₅ metallic glass (MG) powder in its supercooled liquid state by spark plasma sintering. The sintered cores are made from the nanocrystalline powder particles of Fe-Si-B-P-Cu alloy, which are separated through a magnetic Fe₅₅C₁₀B₅P₁₀Ni₁₅Mo₅ MG alloy. Low W of ∼ 2.2 W/kg (at 1T and 50 Hz), and high fracture strength (yielding stress ∼500 MPa), which is an order of magnitude higher than the conventional powder cores, were obtained. Stronger metal-metal bonding and magnetic nature of MG binder (which is very different than the conventional polymer based binders) are responsible for the superior mechanical and magnetic properties. The MG binder not only helps in improving the mechanical properties but it also enhances the overall B_s of the core.