Improvement in brittleness of amorphous Fe-Si-B-C alloy ribbons by controlling casting conditions

Direct measurements of ribbon temperature were performed at a point where the ribbon lifted from off a rotating roll during a conventional single roll process producing amorphous ribbons. A lower ribbon lift-off temperature resulted in a less brittle amorphous state; ductile as-quenched amorphous Fe80.5Si6.5B12C1 alloy ribbons in the thickness range of 52–54 μm were obtained by maintaining the lift-off temperature below 473 K. Thermal analyses indicate that the embrittlement of the ribbons lifted off at temperatures above 473 K may be caused by the structural relaxation, such as the formation of iron clusters, which are introduced to the ribbons after lift-off from the roll.