Combination of AFM, SKPFM, and SIMS to Study the Corrosion Behavior of S-phase particles in AA2024-T351

Loïc Lacroix (1) , Laurence Ressier (2) , Christine Blanc (1) , Georges Mankowski (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 LPCNO - Laboratoire de physique et chimie des nano-objets

The dissolution mechanism of S-phase particles in 2024-T351 aluminum alloy at open-circuit potential in chloride-containing sulfate solutions was investigated using atomic force microscopy (AFM), scanning Kelvin probe force microscopy (SKPFM), and secondary ion mass spectroscopy (SIMS). The combination of the three techniques allowed the correlation between SKPFM measurements and the corrosion behavior of AA2024 to be confirmed, leading to a better understanding of the electrochemical behavior of S-phase particles. A three-step mechanism for the dissolution and accompanying processes occurring near S particles was proposed: (i) preferential aluminum and magnesium dissolution, (ii) galvanic coupling between the copper-enriched particles and the surrounding matrix, leading to an increased passivity of the matrix around the particles, and (iii) copper deposition around the corroded particles.

Mots clés: aluminium alloys; atomic force microscopy; copper alloys; corrosion; dissolving; electrochemistry; magnesium alloys; secondary ion mass spectra

Domaines: Matériaux

Loïc Lacroix, Laurence Ressier, Christine Blanc, Georges Mankowski. Combination of AFM, SKPFM, and SIMS to Study the Corrosion Behavior of S-phase particles in AA2024-T351. Journal of The Electrochemical Society, 2008, vol. 155, pp.C131-C137. ⟨10.1149/1.2833315⟩. ⟨hal-00806024⟩