Effect of Si addition on the nano-structure and soft magnetic properties of bulk Fe-B-based alloys

The effects of Si addition on the nano-eutectic structure and soft magnetic properties of bulk Fe₈₃B_17-xSi_x (x=0-5 at%) alloy rods were investigated. The addition of Si increases the volume fraction of the α-Fe dendrite phase and decreases the average lamellar spacing of the eutectic structure to less than 100 nm. As a result, the intrinsic coercivity (Hc) is decreased effectively, while the saturation magnetization (Ms) remains stable. The annealing experiments of the Fe₈₃B₁₃Si₄ alloy show further that addition of a less than 4 at% Si content can improve the thermal stability of the nano-lamellar eutectic structure and the soft magnetic properties.