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2013-09-02 - Colloque/Présentation - communication orale - Anglais - 1 page(s)

Mouanga Maixent , Andreatta Francesco, Druart Marie-Eve , Marin Elia, Fedrizzi Lorenzo, Olivier Marie-Georges , "Investigation by SVET and microcell of the effect of cerium ions on iron/aluminum galvanic coupling : Application to AA1050 alloy" in EUROCORR2013, Estoril, Portugal, 2013

  • Codes CREF : Chimie des surfaces et des interfaces (DI1327), Corrosion des matériaux (DI2114)
  • Unités de recherche UMONS : Science des Matériaux (F502)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux)
  • Centres UMONS : Ingénierie des matériaux (CRIM)

Abstract(s) :

(Anglais) AA2024 is widely used in aerospace industry due to its mechanical properties. However, it is susceptible to atmospheric corrosion and localized corrosion. To overcome this problem, AA2024 is often cladded with AA1050 alloy containing some iron intermetallic particles. Then, a self-healing coating such as sol-gel or organic coating charged in corrosion inhibitors is deposited on AA1050. Therefore, the choice of the inhibitor to incorporate into these coatings is crucial. This study investigates the inhibition mechanism and kinetics of cerium salts in iron / aluminum galvanic coupling by local electrochemical techniques such as SVET and microcell. For this, we used iron / aluminium electrode model to simulate the electrochemical behavior of iron intermetallic and the matrix. An electrode model consisting of an aluminum rod and an iron rod embedded in an epoxy resin having an area ratio of 1/1 is used. The corrosion inhibition effect of cerium chloride was monitored during 24 hours by SVET technique. Three concentrations (1.25, 2.5 and 5 10-3 mol L-1) were tested to find the optimal concentration for better performance. The synergistic effect between chloride and cerium ions was also discussed and a comparison was done between cerium chloride and nitrate at 2.5 10-3 mol L-1. The importance of the effect of electrode geometry on the SVET response was evidenced by using different area ratios of iron / aluminum galvanic coupling: 1/1, 1/10 and 1/125. The effect of the cerium was also investigated by microcell techniques on the respective aluminium and iron surfaces after 24 h of immersion in the inhibitive solution. These results are interpreted by combining surface analyses such as TOF-SIMS and SEM maps.