Novel Fe–B–P–C–Cu–Co amorphous/nanocrystalline alloys with excellent comprehensive performance via Co substitution for Fe.

The amorphous formation ability, thermal properties, crystallization behavior, magnetic properties, resistivity and bending ductility of Fe 84.5- x B 12 P 2 C 1 Cu 0.5 Co x (x = 0, 4, 8) alloys were systematically investigated. It is found that the substitution of Fe by Co promotes the transformation of the as-spun alloys from a completely amorphous structure to an amorphous/nanocrystalline dual-phase structure, which is related to the differences in the interactions between the involved atoms. The saturation magnetization of alloys increases with increasing Co content and can be increased to 1.93 T at x = 8 by heat treatment, but excessive substitution of Co for Fe deteriorates the coercivity and bending ductility due to the pre-existing α-Fe(Co) grains. The resistivity is positively correlated with the disorder of structure, and the as-spun alloy with x = 4 exhibits a high resistivity of 136.2 μΩ cm. As a result, the annealed Fe 80.5 B 12 P 2 C 1 Cu 0.5 Co 4 alloy with excellent soft magnetic properties (M s = 1.81 T, H c = 7.8 A/m) and good bending ductility in combination with high resistivity has potential for application in the field of electronic devices. • The crystallization tendency of alloy is enhanced by the substitution of Fe by Co. • The annealed Co4 alloy exhibits an ultrafine nanocrystalline structure. • Co4 alloy combines excellent soft magnetic properties with high resistivity. • Co0, Co4 Alloys exhibit good bending ductility even when annealing at T x1 -60 K. [ABSTRACT FROM AUTHOR]