Magnetic properties of (Fe,Co)-B-Al-Nb alloys with ultrafine grain structure

The magnetic properties of (Fe,Co)-B-Al-Nb alloys prepared by rapid solidification process have been studied for the development of a new type Fe-based nanocrystalline alloy. Microstructure composed of ultrafine bcc Fe(Co) has been obtained directly from the rapid solidification by adding 10 at.% Al to (Fe/sub 0.85/Co/sub 0.15/)/sub 80/B/sub 20/ alloy. Furthermore, the addition of 2/spl sim/6 at% Nb to (Fe/sub 0.85/Co/sub 0.15/)/sub 70/B/sub 20/Al/sub 10/ alloy decreases the saturation magnetostriction below 5 ppm. Heat treatment of as-prepared alloys further improves its soft magnetic properties in high frequency range. (Fe/sub 0.85/Co/sub 0.15/)/sub 70/B/sub 18/Al/sub 10/Nb/sub 2/ alloy annealed at 400/spl deg/C for 1 h shows the microstructure composed of ultrafine grains of about 8 nm and the most improved magnetic properties among the prepared alloys.<
>