A localized approach to study the effect of cerium salts as cathodic inhibitor on iron/aluminum galvanic coupling

Highlights: • Cerium chloride is efficient as a corrosion inhibitor for Fe/Al galvanic coupling. • Electrode geometry and the nature of the galvanic coupling affect the SVET responses. • Cerium salts protected the aluminum matrix far from the galvanic coupling. • The anionic parts of the cerium salts can play a significant role. - Abstract: The inhibition effect of cerium salts on iron/aluminum galvanic coupling was investigated by electrochemical microcell and Scanning Vibrating Electrochemical Technique (SVET). The importance of the electrode geometry on the SVET responses was evidenced. The effect of concentration and the influence of the anionic part of cerium salts on the inhibitive efficiencies and protective mechanisms were studied. Cerium salts inhibit the corrosion of iron/aluminum galvanic coupling by reducing the cathodic activity. Microcell analysis confirmed the passivation of aluminum. (SEM + EDS) analyses allowed to understand how the cerium salts act to improve the corrosion behavior