Influence of the oxyanion nature of the electrolyte on the corrosion/passivation behaviour of nickel

• Influence of oxyanion nature on the passivation of nickel.
• Constitutive atoms of oxyanion incorporated into the passive film.
• Evidence of direct bonding between N and Ni surface.

The electrochemical behaviour of nickel in the presence of various electrolyte solutions at 0.1 mol/L concentration exhibits a distinction according to the oxyanion nature of the investigated anions. Passivity is achieved with oxyanions whereas it fails with anions not containing oxygen. SIMS and XPS measurements performed from isotopic and non isotopic KNO3 electrolytes indicate that the oxygen and nitrogen atoms from nitrate oxyanions are incorporated into the passive film during anodic polarization and with evidence of a direct bonding between nitrogen and nickel surface.