Experimental evidence for inhibitor-controlled mechanism of nanocrystallisation in amorphous metallic alloys

The very reason for the formation of nanocrystalline states from amorphous precursors is elucidated for a Fe-based soft-magnetic alloy of Finemet type by means of neutron small-angle scattering. It is shown that the Fe(Si) na nocrystals created in the amorphous matrix during annealing are covered by Nb atoms. The accumulation of Nb atoms or Nb-B aggregates acting as inhibit ors at the surface of the nanocrystals has been assumed within the framewor k of a recent model to be the basic mechanism controlling the evolution of the nanocrystalline state. This model is shown to be correct.