Phase Evolution and Magnetic Characteristic of Fe64Co16 Zr10B10 Amorphous Alloy

Fe64Co16Zr10B10 amorphous alloy prepared by a single roller melt spinning was annealed under isothermal treatment at temperatures ranging from 550 to 650 degrees C in a vacuum. Phase evolution and magnetic characteristic of Fe64Co16Zr10B10 amorphous alloy were investigated in detail by combining X-ray diffraction, transmission electron microscopy, scanning transmission electron microscopy/energy dispersive spectroscopy, and vibrating sample magnetometer. At 550 degrees C, the metastable intermediate alpha-Mn type phase precipitates, as well as an alpha-Fe(Co) phase. At 575 degrees C, only metastable alpha-Mn type phase is observed. Scanning transmission electron microscopy/energy dispersive spectroscopy indicates that the alpha-Mn type nanocrystals contain Fe, Co, and Zr. More Zr is at the interface between the nanocrystals and the amorphous matrix. There is little change in Co concentration among the remaining amorphous matrix, the nanocrystals, and the interface between the nanocrystals and the amorphous matrix. With a further increase in annealing temperature, the crystallization volume fraction of the alpha-Mn type phase decreases, and the crystallization volume fraction of the alpha-Fe(Co) phase increases accordingly. Coercivity of Fe64Co16Zr10B10 alloy undergoes a sharp rise above 550 degrees C and a sharp decline above 600 degrees C.