A novel approach for mechanical alloying amorphisation in magnetic Fe–Co alloy system

Abstract

The aim of this work is to investigate the possibility to extend the formation of amorphous phase in Fe–Co based system without compromising their magnetic properties. For this purpose, a novel approach was used in which different elements were added during mechanical alloying (MA) with a specific trend. Elements such as Ti, Al, Si, B, P and C enhance amorphisation of iron-based alloy by mechanical alloying (MA) based on thermodynamic and kinetic considerations. In contrast, Co obstructs the amorphisation reaction by MA. Therefore to obtain fully amorphous structure in Fe–Co magnetic alloy chronological addition of elements was applied. In first step, (Fe50Ti25Al25)70 was ball milled to obtain (Fe, Ti)3Al intermetallic compound, then, (B15P7C6Si2)30 was added to (Fe, Ti)3Al and an amorphous-nanocrystalline state was achieved. Finally 20 at% Co was added to incorporate Co in the amorphous alloy through continued ball milling for 60 h. In this way a full amorphous structure was achieved in (Fe50Ti25Al25)70B15P7C6Si2–Co20 composition with superior magnetic properties. Structural analysis verified experimentally with x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDS) mapping and transmission electron microscopy (TEM). Further, magnetic properties was investigated by vibrant sample magnetometer (VSM).