Structural and magnetic characterization of composite YCo5/α-Fe (20 wt%) powders prepared by mechanical alloying and subsequent annealing

Powder mixtures of YCo5 + α-Fe (20 wt%) were prepared by high energy mechanical alloying under Ar using a SPEX 8000 mill and subsequent vacuum annealing. The structural and magnetic properties were investigated by X-ray diffraction, DSC, and magnetic measurements. After 4 h of milling, the alloyed powders were found to be composed of an amorphous Y–Co phase and α-Fe with a mean grain size strongly reduced. The DSC curves exhibited an irreversible broad exothermic peak with a maximum at 555 °C associated with the crystallization process. Subsequent high vacuum annealing in the temperature range 550–750 °C led to the formation of rhombohedral Th2Zn17-type and α-Fe(Co) phases. Samples were magnetically soft showing low remanence and room temperature coercivity in the range 470–800 Oe. The latter is in agreement with the low magnetocrystalline anisotropy along the basal plane exhibited by the Y2(Co, Fe)17 phase.