Improving the glass formation ability and magnetic properties by Nb in Fe-Si-B-P-Cu-Nb nanocrystalline alloys

Fe-based nanocrystalline alloys with high saturation flux density (B s ) are highly desired for the miniaturization of electronic devices. However, the glass forming ability (GFA) and the temperature window of annealing processing of the high Fe content nanocrystalline alloys need to be improved to satisfy the industrial production. In this work, the influence of Nb on the GFA, crystalline behavior, soft magnetic properties of melt-spun Fe86.3-x-Si1.3B8.9P3Cu0.5Nbx (0 <= x <= 4) alloys have been comprehensively investigated. It has been found that full amorphous structure can be obtained when the content of Nb is more than 3 at. %, and Nb may play a critical role in the optimization of crystalline processing. It has been also demonstrated that alpha-Fe (Si) grains were obviously refined by Nb so as to result in the decease of coercivity (H-c). In this work, Fe82.3Si1.3B8.9P3Cu0.5Nb4 ribbon exhibits an H-c of 4.2 A/m after relaxation, and a B-s of 1.54 T after annealed at 500 degrees C, respectively, which are comparable to those of NANOPERM alloys.

Automated summary

Fe-based nanocrystalline alloys with high saturation flux density are desired for electronic device miniaturization, but improvements in glass forming ability and annealing temperature window are needed for industrial production. This study comprehensively investigated the influence of Nb on the properties of Fe-Si-B-P-Cu-Nb alloys, finding that Nb plays a critical role in crystalline processing optimization. Nb refinement of alpha-Fe (Si) grains led to reduced coercivity and comparable soft magnetic properties to NANOPERM alloys in Fe82.3Si1.3B8.9P3Cu0.5Nb4 ribbon.