Compositional effect on the magnetic and microstructural properties of Fe-based nano-crystalline alloys

The soft magnetic properties of Fe-based nano-crystalline alloys depend on the size, shape and crystallization ratio of nanocrystals formed during annealing. To increase saturation magnetization, soft magnetic properties should be reduced by increasing Fe content. Amorphous Fe-B-C-Cu alloys have been reported to be successfully fabricated despite a Fe content of more than 84%. However, clustered rectangular nano-grains were formed during annealing, resulting in an increase in magnetic loss. In this study, to induce the uniform formation of nuclei and suppress crystal clustering, the effects of C, Cu and Nb on the magnetic and microstructural properties of Fe(81-x)B12.5CyCuxNb(6.5-y) (x = 0, 1, 2 and y = 1, 2, 3, 4) were investigated. The results indicated that thermal stability played an important role in the formation of uniformly distributed spherical nano-crystals during annealing.