ON THE NATURE OF THE REMAINING AMORPHOUS MATRIX AFTER NANOCRYSTALLIZATION OF FE77SI14B9 WITH CU AND NB ADDITION

FeSiBNbCu amorphous alloys usually crystallize in two stages. The firs t crystallization stage for near-eutectic and hypoeutectic composition s corresponds to the nucleation and growth of alpha-Fe(Si) nanocrystal s. The surrounding amorphous matrix in turn crystallizes in the second stage which occurs at high temperatures. We have measured the variati ons in the Curie temperature T(c) and crystallization temperature T(x) with composition of the remaining amorphous matrix after alpha-Fe(Si) nanocrystallization and found that the remaining amorphous matrix con tains only 3-4 at.% Nb. Mass balance considerations then impose the co nclusion that, contrary to some previous reports, the alpha-Fe(Si) nan ocrystals still contain at least 1.5 at.% Nb. This conclusion is shown to be consistent with the lattice parameter and magnetic properties o f the alpha-Fe(Si) nanocrystals.