Improvement of soft magnetic properties for Fe-based amorphous/nanocrystalline alloy by longitudinal magnetic field annealing
Mufeng Jiang, Jingjing Wang, Mingjuan Cai, Jun Li, Wanying Dong, Zhijun Guo, Baolong Shen
Abstract
This study investigated the enhancement of soft magnetic properties in Fe 83.2-x Co x Si 2.5 B 9.5 P 4 Cu 0.8 ( x = 0, 4, 8, 12 and 16 at %) amorphous/nanocrystalline alloys through longitudinal magnetic field annealing (FA). The FA-treated alloys demonstrate superior magnetic performance, achieving a superior saturation flux density ( B s ) of 1.85 T, ultra-low coercivity ( H c ) of 1.8 A/m, high effective permeability ( μ e ) of 26,505 at 1 kHz, and low core loss (0.13 W/kg) at 1.0 T/50 Hz. Microstructural analysis reveals that the FA and Co substitution promotes nanocrystalline nucleation, forming high-density nanocrystals while suppressing grain growth through competitive dynamics and inhibiting element diffusion within the amorphous matrix. Domain observation further confirms that FA facilitates the transition from disordered, non-uniform magnetic to uniform, broad, plate-like domains. These findings elucidate the critical influence of longitudinal magnetic field annealing on microstructure evolution and magnetic domain alignment, which synergistically enhance soft magnetic properties.