Achieving excellent soft magnetic performance in FeCoBSiCu alloy through composition-processing regulation

The overwhelming evolution of electronic devices has put forward more urgent performance demands for soft magnetic materials, especially for the higher saturation magnetic induction intensity (B_s) and the lower coercivity (H_c). Nevertheless, there is extremely rare material candidate satisfying the B_s approaching 2 T and the H_c below 10 A/m. In this study, we adopted three composition modulation strategies (i.e., replacing Si with Fe/B/Cu) on FeCoBSiCu alloy to systematically perform crystallization thermal processing with magnetic field assistance, and ultimately achieved the controllable transition of structure-performance from amorphous to nanocrystalline alloys. Especially, the newly developed Fe_68.4Co_17.5B₁₃Si_0.3Cu_0.8 (B_s = 1.99 T, H_c = 8.1 A/m) characterized as a glassy matrix with relatively high crystallization volume fraction of α-Fe(Co) nanocrystals, owns ultra-high B_s approaching the performance of ultra-fast annealing alloys, and Fe_68.2Co_17.5B_13.4Si_0.1Cu_0.8 (B_s = 1.91 T, H_c = 0.9 A/m) dominated by amorphous structure, possesses the highest B_s on the premise of H_c below 1 A/m. The ideas of composition-processing regulation are anticipated to efficiently guide and accelerate the development of novel soft magnetic materials with excellent performance.