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 10at. % Al to (Fe.Co-85.(15))(80)B-20 alloy. Furthermore, the addition of 2 similar to 6 at.% Nb to (Fe.Co-85.(15))(70)B20Al10 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.Co-85.(15))(70)B18Al10Nb2 alloy annealed at 400 degrees C for 1 h shows the microstructure composed of ultrafine grains of about 8 nn and the most improved magnetic properties among the prepared alloys.