The crystallization in Finemet with Cu substituted by Ag

Abstract The amorphous ribbon Fe73.5Si13.5B9Nb3Ag1 has been prepared by rapid cooling on a single copper wheel. The DSC curves show the very sharp peak at 593–617 °C depending on the heating rate from 10 °C/min to 50 °C/min, which is higher than that for pure Finemet (540–572 °C, respectively). The crystallization activation energy of α-Fe(Si) phase has been determined and shown to be E = 4.09 eV , higher than that of pure Finemet ( E = 3.25 eV ) . After annealing at 550 °C for 10 min, the crystallization volume fraction of α-Fe(Si) phase reaches the value of 78.4% with average grain size of 32 nm. The M(T) measurement along cooling cycle exhibits clearly two-step curve corresponding to the multiphase structure of the ribbon. The annealing of ribbon leads to the occurrence of nanocomposite state and improvement of soft magnetic properties of the material.