STRUCTURE INVESTIGATIONS ON ANNEALED FE(CUNB)SIB ALLOYS WITH DIFFERENT SI-B CONTENTS

The structure of three alloys Fe73.5Cu1Nb3Si22.5-zBz with z = 5, 9, an d 14 is examined in the nano- and microcrystalline states. This alloy system is very interesting for technical applications because of its n anostructure causing very soft magnetic properties together with low m agnetostriction. The Si and B concentrations influence the number and the temperature of phase transitions as well as the grain size, compos ition, and structure of the nano- and microcrystals which develop whil e annealing the as-cast amorphous alloys. The specific electrical resi stivity and magnetization are measured as function of temperature at w ell-defined heating rates. These measurements allow to determine chara cteristic temperatures which indicate the phase formation of nano- and microcrystals. Furthermore the Curie temperatures of phases being fer romagnetic are helpful for phase identification. The detailed phase an alysis of differently annealed samples is done by X-ray diffraction an d Mossbauer spectroscopy. The combination of hyperfine field and diffr action data allows us to ensure the existence of new phases.