Effect of P on crystallization behavior and soft-magnetic properties of Fe_83.3Si₄Cu_0.7B_{12 - X}P_x nanocrystalline soft-magnetic alloys

The P content dependences of the crystallization behavior, thermal stability and soft-magnetic properties of high Fe content Fe _83.3Si₄Cu_0.7B_{12 - x}P_x (x = 0 to 8) nanocrystalline soft-magnetic alloys were investigated. P addition is very effective in widening the optimum annealing temperature range and refining of bcc-Fe grain size in addition to the increasing of nanocrystalline grain density. Uniform nanocrystalline bcc-Fe grains with average size of about 20 nm and number density of 10²³-10²⁴ /m³ were prepared at around x = 6-8 for the annealed Fe_83.3Si ₄Cu_0.7B_{12 - x}P_x alloys. The coercivity H_c markedly decreases with increasing x and exhibits a minimum at around x = 6-8, while the saturation magnetic flux density B _s shows a slight decrease. Fe_83.3Si₄Cu _0.7B₆P₆ nanocrystalline alloy exhibits excellent soft-magnetic properties with a high saturation magnetic flux density B_s of 1.77 T, low coercivity H_c of 4.2 A/m and high effective permeability μ_e of 11,600 at 1 kHz.