Abstract:Fe44Co20Nd7Nb4B25 bulk amorphous alloy was prepared by copper mold casting. The microstructure, glass-forming ability, thermal stability and magnetic properties were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). It is found that Fe44Co20Nd7Nb4B25 alloy with amorphous structure exhibits good soft magnetic property, excellent glass-forming ability and thermal stability. The value of activation energy, Ep, is 642 kJ/mol. The annealed sample shows hard magnetic behavior, and the maximum value of intrinsic coercivity (iHc) is 1164 kA/m after annealing at 1003 K. When annealed at 963 K, the values of remanence (Br) and maximum energy product ((BH)max) reaches a maximum of 0.27 T and 15.79 kJ/m3, respectively