Potentiodynamic and potentiostatic investigation on the passivation of Fe based glassy alloys in alkaline solution

The effect of Nb element on the corrosion resistance of Fe-based metallic glasses in the alkaline environment has been investigated with various techniques like potentiodynamic polarization test, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and potentiostatic tests. With increasing the Nb content, the passivation stability of as spun Fe87-xB13Nbx (x = 0, 7 and 10) glassy ribbons increases and the thickness of their passive film decreases according to XPS analysis. In the potentiostatic test, the ribbons have a transition potential E-trans of -0.58, -0.47 and -0.38 V-SCE with x = 0, 7 and 10 respectively, showing an increasing passivation stability with increasing x, which is more sensible than the potentiodynamic parameters like i(pass) and E-pit. Meanwhile, Nb element has the ability to repair pitting holes. In potentiostatic test, the long constant potential treatment below E-trans may enhance the generation of ribbon's passivation film, indicating that the potentiostatic test can tune the passivation behavior of metallic alloys. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The addition of Nb element enhances the corrosion resistance of Fe-based metallic glasses in alkaline environments, increasing the passivation stability, reducing the thickness of the passive film, and repairing pitting holes. Results from potentiostatic tests and potentiodynamic tests demonstrate that Nb element can tune the passivation behavior of metallic alloys.