High temperature soft magnetic property of the nanocrystalline Fe44Co44Zr7B5 alloy arising from Ge addition

Melt spinning technique was used to prepare FeCoZrBGe, FeCoZrBCu and FeCoZrB alloys. High-resolution electron transmission microscopy observations reveal that the annealed alloys exhibit a typical two-phase microstructure characterized by FeCo nanocrystallites of 10 nm embedded in an amorphous phase. The addition of Ge in the FeCoZrB alloy is found to increase the stability of the residual amorphous phase, resulting in the suppression of grain growth and lower coercivity at elevated temperatures with respect to the Ge-free alloys.