FeCo-based amorphous alloys with high ferromagnetic elements and large annealing processing window

A seven-component (FeCo)xBSiVCuY amorphous/nanocrystalline alloy system with high ferromagnetic element contents (x = 85, 86 and 87, at atomic percent) was synthesized by rapid quenching method. The microstructure, crystal structure, magnetic property and crystallization behavior were systematically investigated. It is found that the highest saturation magnetization of these as-cast ribbons reaches 1.80 T. Upon heating, two different crystal precipitated phases bcc-Fe (Co) and Fe-metalloids appear successively with temperature intervals (ΔTx) as large as 193 K. Comparing with typical Fe-based amorphous/nanocrystallization alloys, (Fe0.8Co0.2)87B10Si1V0.5Cu0.5Y1 alloy shows an ultra-low primary crystallization activation energy and a large secondary crystallization activation energy, indicating an extremely large annealing temperature window more than 200 K beneficial for their processing. Therefore, this series of amorphous alloys provide potential precursors with decreasing annealing temperature and time for producing ferromagnetic nanocrystalline alloys, which can significantly reduce the cost for industrial production. •Ultra-high ferromagnetic element content of 87 atomic% was achieved in (FeCo)xBSiVCuY amorphous/nanocrystalline alloys.•The highest saturation magnetization of these as-cast ribbons can reach 1.80 T.•Significant different crystallization activation energies exist in the primary and secondary exothermic peaks.•A large annealing temperature window about 200 K facilitates to obtain dual-phase with improved magnetic properties.