Investigations on the electrochemical behavior of Zr-Al-Cu-Ni bulk metallic glass

The passivation behavior of bulk glassy Zr55Al10Cu30Ni5 ahoy samples in weakly alkaline sulphate solution (pH = 8) is investigated in comparison to the are-melted crystalline alloy, to the main alloying component zirconium and to aluminium. Results of potentiodynamic and potentiostatic polarization measurements reveal the formation of a stable passivating surface film on the glassy alloy grown by a high-field mechanism. Auger electron spectroscopic investigations of anodized sample surfaces show that the films formed on the glassy Zr-Al-Cu-Ni alloys exhibit a composition gradient in cross-sectional direction. In 0.001M NaCl electrolytes bulk glassy Zr-Al-Cu-Ni samples are susceptible to pitting corrosion, which is due to the existence of crystalline inclusions.