Nanocrystallization of amorphous Fe-Si-B alloys using high current densityelectropulsing

Amorphous Fe-Si-B ribbons were nanocrystallized by using high current densi ty de electropulsing instead of the usual annealing. The microstructural ch anges were investigated by TEM, SAD, XRD, and Mossbauer spectral analysis. It was found that current pulsing promotes crystallization at a lower tempe rature than the usual annealing temperature. The primary crystallization te mperatures of Metglas 2605 S-2 and Finemet were significantly lowered by pu lsing. This enabled us to obtain 20-30 vol.% of single phase, alpha-Fe(Si) with a grain size of 15-20 nm in Metglas 2605 S-2. As a consequence, certai n magnetic properties of this material are improved with respect to the as- quenched state. A preliminary interpretation is given for the phenomenon of electro-nanocrystallization. (C) 2000 Elsevier Science S.A. All rights res erved.