Effect of W Addition on Fe-P-C-B Soft-Magnetic Amorphous Alloy

In this work, the thermal behavior, soft magnetic properties, and structure of Fe_86-xP₁₁C₂B₁W_x (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, and 4) amorphous alloys were researched by several experimental methods and ab initio molecular dynamics. The addition of W improved the thermal stability of the alloy system when the first onset crystallization temperature (T_x1) increased from 655 K to 711 K, significantly reduced the coercivity H_c, and decreased the saturation magnetization B_s. The Fe_85.6P₁₁C₂B₁W_0.4 alloy showed optimal soft magnetic performance, with low H_c of 1.4 A/m and relatively good B_s of 1.52 T. The simulation results suggested that W atoms increased the distance of the neighboring Fe-Fe pair, reduced the coordination number, narrowed the gap between the spin-up and spin-down electrons of each atom, and decreased the average magnetic moment of the Fe atoms. This work demonstrates a micro-alloying strategy to greatly reduce H_c while maintaining high B_s.