Soft magnetic properties and microstructure of novel Nb poor Finemet type alloys

AbstractSeries of Nb poor Finemet type alloys were fabricated by substitution of Nb by Al for the first time, and soft magnetic properties of them have been researched by using permeability spectroscopy and X-ray diffraction. It is found that with 0·5 at.-% substitution of Nb by Al, the initial permeability is improved drastically, and the relaxation frequency is enhanced as well, and the loss factor reduces to a very low value of the order of 10−6 in the low frequency range compared to conventional Finemet. The improved soft magnetic properties are related to the lower crystalline anisotropy of FeSiAl compared to FeSi and the proper crystalline volume fraction. This research shows that the substitution of Nb by Al in Nb poor Finemet type alloys can bear ultrasoft magnetic properties at less cost.