The effects of quenching conditions on the electrochemical behaviour of Fe34Ni36Cr10P14B6 amorphous alloy

The influence of quenching conditions on the anodic behaviour of amorphous Fe34Ni36Cr10P14B6 alloy in 1 N H2SO4 and 1 N HCl solutions has been investigated by means of standard electrochemical techniques accompanied by Auger electron spectroscopy and scanning electron microscopy. Both sides of 20 and 60-mu-m thick ribbons prepared by the planar flow casting technique at two different quenching rates were tested. Strong similarities have been found between the anodic behaviour of the surfaces which underwent the fastest quenching rates (both sides of the 20-mu-m thick ribbons and the dull sides of the 60-mu-m thick ribbons) while more noble corrosion potentials and lower currents of passivity were displayed by the shiny sides of the 60-mu-m thick ribbons, which underwent the lowest quenching rate. These results are interpreted as the result of concurrent factors related both to the chemical composition of the passivity films and to the characteristics of the amorphous structure, i.e. the amount of quenched-in defect