Crystallization behaviour of amorphous Fe73.5Cu1Nb3Si13.5B9

Abstract

Iron-based amorphous alloys have attracted technological and scientific interest due to their soft magnetic properties. Recently it was found that amorphous alloys like Fe_73.5Cu₁Nb₃Si_13.5B₉ (FINEMET^TM) have a transition to the nanocrystalline state after proper annealing, thus exhibiting excellent magnetic properties. An attempt was made to investigate the crystallization behaviour of this alloy, which is not yet fully known. The investigation was carried out by combining several methods, namely Mossbauer spectroscopy, X-ray diffraction, scanning and transmission electron microscopy as well as microprobe analysis. The alloy was studied after annealing at various temperatures for various times. The corresponding phase analyses are presented. Even after increasing the time of annealing at 950 degrees C from 1 h to 90 h significant changes in the phases were found. It became evident that the question of phase composition can be solved only by a combination of different methods.