Influence of Al and Ni on the magnetic properties of Finemet alloys

Crystallization behavior and soft magnetic properties of the FeSiBCuNbM (M=Al or Ni) Finemet alloys are investigated by X-ray diffraction, differential scanning calorimetry, hysteresis loop tracer, and vibrating sample magnetometry. The nanocrystalline alloys are prepared by annealing melt-spun amorphous ribbons at different temperatures. Results indicate that the partial substitution of Ni or Al for Nb results in the increase of saturation magnetic induction density (Bs) of the alloys. The alloys with Al or Ni show favorable combination of soft magnetic properties. The partial substitution of Ni for Nb enhances the Bs value, while Al decreases coercivity. The mechanism underlining the magnetic behavior is discussed.