A microscopic and impedance spectroscopy study of Finemet–Co amorphous alloys

Abstract Structural characterization of some Finemet–Co alloys is performed by scanning and transmission electron microscopies. The results show a response independent of the composition and state. In addition to this, electrode impedances were measured in 0.5 N KOH water solution. Three time constants were found for the electrode reaction at open circuit potential. The effect of cobalt addition was analyzed as well as the influence of the thermal treatment (TT). The values of the different parameters indicates that both, the substitution of iron by cobalt and the TT result in the increase of the stability of the oxide layers.