Extremely high Bs (Fe1-xCox)86Ni1B13 amorphous soft magnetic alloys with good bending ductility

Abstract The effects of Co content on the thermal stability, soft-magnetic properties, corrosion resistance and mechanical properties of (Fe1-xCox)86Ni1B13 (x = 0–0.25) amorphous alloys were systematically investigated. Adequate Co addition can significantly increase saturation magnetic flux density (Bs). Extremely high Bs of 1.78–1.92 T was obtained when Co content was added in the range of x = 0.05–0.25. Besides, the Curie temperature (Tc) increases markedly with the introduction of Co, exhibiting the high thermal stability of soft magnetic properties. Compared with x = 0 (Co-free) alloys, the Tc of x = 0.1 (0.1Co) alloy increases more than 100 K, far exceeding the first crystallization temperature. There is also an obvious increase in temperature intervals between the two exothermic peaks of crystallization with Co content, implying high thermal stability of the Co-containing alloys. In addition, the corrosion resistance of 0.1Co alloy was also improved compared with the Co-free alloy. Among the (Fe1-xCox)86Ni1B13 amorphous alloys, the one with 0.1Co simultaneously exhibits high Bs of 1.87 T and low Hc of 10 A/m, as well as good bending ductility at annealed state. Moreover, the underlying mechanisms of the good ductility of the 0.1Co alloy annealed under the optimal condition was also discussed from the perspective of atom bonding nature. The combination of extremely high Bs and low Hc in conjunction with good manufacturability makes the (Fe0.9Co0.1)86Ni1B13 alloys promising soft-magnetic materials for potential applications.