Changes in Microstructure and Magnetic Properties of Fe–B–Cu–C Ribbons According to Annealing Conditions

Rapid solidification process (RSP) has been widely used to fabricate Fe-based nanocrystalline alloys. To obtain amorphous structure after RSP, the number of Fe elements in the nanocrystalline alloys is limited by the amount of amorphous forming elements. Recently, strong demand for high energy efficiency electronic devices has pushed researchers to make Fe-based alloys with high magnetic flux density. However, this high Fe concentration for high magnetic flux density deteriorates the thermal stability of the amorphous structure. This means that an annealing process after RSP is critical to obtain excellent alloy magnetic properties. In this paper, to enhance the soft magnetic properties of amorphous Fe-B-Cu-C ribbons, changes in the microstructure during annealing have been investigated.