Ferromagnetic element microalloying and clustering effects in high B_s Fe-based amorphous alloys

Fe₈₃(Co_x,Ni_y)(B₁₁Si₂P₃C₁)_1-x,y/17 (x, y = 1–3) amorphous alloys with high saturation magnetic flux density (B_s) and excellent soft-magnetic properties were developed and then the microalloying and clustering effects were explored. The microalloying of Co and Ni improves the B_s from 1.65 T to 1.67–1.72 T and 1.66–1.68 T, respectively. The Ni-doped alloys exhibit better soft-magnetic properties, containing a low coercivity (H_c) of about 5.0 A/m and a high Effective permeability (μ_e) of (8–10) × 10³, whereas the microalloying of Co leads to a deteriorative H_c of 5.0–13.0 A/m and a μ_e of (5–8) × 10³. Moreover, microalloying of Ni can increase the ductile-brittle transition (DBT) temperature of the ribbons, while a totally opposite effect is found in the Co-doped alloys. The formation of dense α-Fe(Co,Ni) clusters during annealing process is used to explain the distinct effects of Co and Ni microalloying on the magnetic properties and bending toughness.