Abstract
The effects of the structural inhomogeneity, volume fraction (va), and Curie temperature (Tcam) of an inter-granular amorphous phase on the soft magnetic properties of nanocrystalline Fe-Nb-B(-P-Cu) alloys were investigated. The Fe85Nb6B9 alloy has a mixed as-quenched structure composed of an amorphous phase and α-Fe grains, and an inhomogeneous nanostructure including coarse α-Fe grains with a diameter of about 40 nm after crystallization. The simultaneous replacement of B by 1 at% P and Fe by 0.1 at% Cu in the alloy decreases the α-Fe grain size to the nano-scale in an as-quenched state and leads to a homogeneous nanostructure, small va, and high Tcam after crystallization. Analysis based on the random anisotropy model shows that a homogeneous nanostructure with small va and high Tcam provides good soft magnetic properties.
