Magnetic properties of Fe-6.4wt% Si ribbons

Abstract

Thin Fe6.4wt.%si ribbons were produced by melt spinning. High temperature recrystallizations, performed at 1025ºC in a hydrogen atmosphere, were found to produce the lowest Hc values (19 A/m. Further agings were carried out at 50ºC intervals in the range 400-7°C to optimize the magnetic properties. For all ribbons we measured Hc (60 Hz and DC), the maximum permeability fim,, the saturation magnetostriction A, and the effective anisotropy constant Keff In general, the agings did little to improve the magnetic properties, and those around 600-C resulted in their deterioration. Extensive TEM investigations of the ribbons indicate that the dendritic structure of the as-cast material disappears after recrystallization, leading to a more uniform distribution of Si as well as a more homogeneous ordering. The 600ºC aging results in a marked anisotropy in the B2 antiphase boundaries and the growth of oxide particles, which lead to a deterioration of the magnetic properties.