As-cast nanocrystalline glass-coated microwires

As-cast nanocrystalline Fe74.5−xSi9B13.5CuxNb3 (x = 1 and 2.5 at.%) glass-coated microwires have been prepared by drawing from the melt in a single step process. The cooling conditions and Cu content were modified in order to facilitate the growth of α-(Fe,Si) nanograins directly from the wire formation process. By increasing the cooling distance, the microstructure evolves from a fully amorphous one at low cooling distances to a nanocrystalline central area and an amorphous shell towards the surface at higher cooling distances. Changes of the composition and cooling conditions allow an extensive tailoring of the magnetic properties and structure of the as-cast glass-coated microwires.