Structural aspects and the anodic behaviour of Fe34Ni36Cr10P14B6 amorphous alloy submitted to different heat treatments

The influence of heat treatments on the anodic behavior and on the structure of Fe34Ni36Cr10P14B6 amorphous alloy, in 1 N H2SO4 and 1 N HCl solutions, has been studied by standard electrochemical techniques associated with x-ray diffraction analysis, differential scanning calorimetry and Auger electron spectroscopy. The as-quenched amorphous alloy displays very good corrosion performance in the testing environments. Heat treatments (from 150 to 500degreesC) induce structural relaxation processes and the amorphous to crystalline transition, thus bringing about contrasting effects on the corrosion resistance of the material. A superior performance has been observed in specimens annealed for 2 h at 350degreesC. The presence of an oxide surface layer is revealed by AES. A detailed analysis of the influence of structural and compositional aspects is given.