Crystallization and Magnetic Properties of Fe-Co-Nd-Zr-B Amorphous Alloys

Abstract

New Fe-based amorphous alloys exhibiting the glass transition and supercooled liquid region before crystallization were searched for in the composition range of Fe63Co7Nd10-xZrxB20 (x=0 to 6 at%). Amorphous alloys containing 4 to 6 at%Zr were found to exhibit the glass transition followed by a supercooled liquid region. The crystallization of the 4 at%Zr and 6 at%Zr alloys occurred in three stages. In the crystallized state, the alloys exhibited hard magnetic properties, namely, Js of 1.15 to 1.18 T, Jr of 0.75 to 0.76 T, and Nd2Fe14B phases for the 4 at%Zr alloy subjected to optimum annealing were about 50 nm and 30 nm, respectively, and the exchange magnetic coupling interaction between the α-Fe and Nd2Fe14B phases is thought to make possible the appearance of the hard magnetic properties.