Influence of Cr content in Fe/Cr alloys on the adsorption behaviour of Cl⁻ ion in pH=2 acid solution

The paper aims to investigate the effect of Cr content on Cl⁻ adsorption behaviour.

The adsorption behaviour of Cl⁻ on Fe-xCr (x = 10, 20, 30, 50, 75 At.%) alloys in HCl + NaCl solution (pH = 2, [Cl−] = 0.1 M) has been studied by electrochemical techniques, X-ray photoelectron spectroscopy and first-principle calculations.

The results show that both the adsorption energy and distance decreased with increasing Cr content, which shows the adsorption of Cl⁻ is dependent on the amount of Cr present. Cr oxides of the passive films on Fe50Cr and Fe75Cr alloys inhibited the adsorption of Cl⁻.

Investigation of the relationship between the Cr content and the role of Cl⁻ adsorption provides a reliable basis for the design of corrosion-resistant alloys.