Ab initio study of influence of 3d alloying elements on corrosion properties of non-passivated nickel-base alloys

The paper systematically studies the impact of the 3d transition metals Sc, Ti, V, Cr, Mn, Fe, Co, Cu, and Zn on electrochemical stability of non-passivated nickel-base alloys {1 1 1} surface by evaluating the chemical potential and the electrode potential shift relative to pure nickel metal using density functional theory calculations. Among all 3d alloying elements, only the element Cr is found to make the surface Ni atoms more stable on the {1 1 1} surface of the corresponding alloy compared to pure Ni {1 1 1} surface, whereas Sc, Ti, V, Mn, Fe, Co, Cu, and Zn make Ni atoms much less stable. Furthermore, the effects of water adsorption on the electrochemical stability are considered. It is found that the surface adsorption properties may be considerably modified by introducing the Cr atoms. Our results indicate that water adsorption destabilizes both the Ni–Cr alloy and pure Ni surface. However, the Ni–Cr alloy surface is still more stable than the pure Ni surface in the presence of adsorbed water. It is confirmed that the strengthen of water-surface bonding is followed by loss of bonding within the surface and the adsorbed water molecules. Our calculation reveals that for the electrochemical corrosion property, the Ni–Cr alloy is insensitive to water molecular adsorption in comparison with the pure Ni metal.