Corrosion behavior of the bulk glassy (Fe_44.3Cr₅Co₅Mo_12.8Mn_11.2C_15.8B_5.9)_98.5Y_1.5 alloy

The free corrosion behavior and the anodic passivation ability of the bulk glassy (Fe_44.3Cr₅Co₅Mo_12.8Mn_11.2C_15.8B_5.9)_98.5Y_1.5 alloy were fundamentally analyzed. Electrochemical tests were performed in aqueous solutions with pH values in the interval 0.3–14. Corrosion current densities are below 3 μA/cm² in the entire studied pH interval; compared with commercial grade steels, for example, X210Cr12 steel, the glassy alloy has lower corrosion rates in acidic electrolytes and higher in basic solutions. The alloy exhibits high dissolution rates upon anodic polarization in acidic environments, but with increasing pH values it tends to form passive layers showing the lowest passive current density at pH 11. The passive layers consist mainly of Fe and Cr oxides. There is a strong variation of the passive layer structure and composition with pH. The protective effect of the grown surface layers is negatively influenced by sulfate ions.