Electrochemical Analysis of Nb Content in Corrosion Behavior in Binary Ni–Nb Metallic Glasses in Chloride‐Containing Media

The corrosion behavior of three metallic glasses in 0.5‐M NaCl solution was analyzed using electrochemical impedance spectroscopy (EIS) and cyclic polarization curves (CPCs). The metallic glass compositions tested were hypoeutectic (Ni 61.5 Nb 38.5 ), eutectic (Ni 59.5 Nb 40.5 ), and hypereutectic (Ni 57.5 Nb 42.5 ); these three compositions showed a fully glassy structure by means of X‐ray diffraction (XRD). EIS showed two coupled time constants, one attributed to the passive film and the other to the double layer. As the Nb content increases, the corrosion resistance also increases, with higher values of R tot . The system exhibited pseudopassivation at approximately 10 6 A/cm 2 in cyclic polarization curves and a negative hysteresis when the potential was reversed. Lower i corr values of the reversed potential were associated with a pitting–sealing phenomenon related to the high stability of the niobium oxide, providing the studied metallic glasses with high homogeneous and localized corrosion resistance. By means of SEM, no visible damage was observed in the investigated alloys.