Crystallization behavior and high temperature magnetic phase transitions of Nb-substituted FeCoSiBCu nanocompositesof

The effect of Nb substitution on the nanocrystallization process and high temperature magnetic properties of FeCoSiBCu nanocomposites is reported. Magnetization changes accompany the primary crystallization of a-Fe(Co) nanocrystals and the secondary crystallization of (FeCo)23B6 and (FeCo)2B phases. With increasing the Nb fraction in the alloys, the diffusion barrier to growth of alpha-Fe(Co) nanocrystals increases, resulting in an increase of thermal stability and a delay of Fe(Co) dissolution required for (FeCo)23B6 phase formation. The transmission electron microscopy images reveal finer grains with increasing Nb content