INVESTIGATIONS ON THE GRAIN-GROWTH PROCESSES IN NANOCRYSTALLINE FE73.5CU1NB3SI16.5B6

The structure formation in the amorphous matrix and the growth of crystallites subject to a heat treatment in the alloy of the type Fe73.5Cu1Nb3Si16.5B6 is obtained using XRD and SAXS. A combination of the results gained by both methods leads to conclusions concerning the behavior of the crystalline and amorphous phases. The existence of a crystalline phase (Fe3Si) in the annealed samples is proved with XRD. The crystal size increases with the annealing temperature and comes up to 15 nm in diameter (600-degrees-C, 1 h). XRD studies show that the as-quenched sample is completely amorphous. The amorphous sample causes small angle scattering, leading to the conclusion that it contains nanoamorphous demixing structures. The size of these demixing structures is equal to the size of the crystallites after heat treatment of 1 h at 550-degrees-C. This is the state with the best soft magnetic behavior of this material. Further the anisotropic growth of the nanocrystallites due to a direct current heat treatment is investigated.