The native oxide film on a model aluminium-copper alloy studied by XPS and ToF-SIMS. (September 2020)

• Record Type: Journal Article
• Authors: Cornette, P.; Zanna, S.; Seyeux, A.; Costa, D.; Marcus, P.
• Is Part Of: Corrosion science. Volume 174(2020)
• Publication Date: 2020-09
• Subjects: Aluminium alloy -- XPS -- ToF-SIMS -- Surface oxide; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2020.108837
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: The oxide formed on Al-Cu2.2 % at alloy is investigated by ToF-SIMS and XPS. Al2 Cu intermetallic particles (IMPs) are present at the metal/oxide interface with a surface coverage of 3.2 %. A 3 nm thick aluminium oxide covers the matrix whereas the oxide is thinner above the IMPs protruding into the oxide layer. Copper oxide islands (0.5 nm thick) are present on the IMPs and the surface coverage is approximately 2.5 % of the surface. Copper enrichment at the metal/oxide interface is revealed for both the Al matrix and the IMPs. Abstract: Surface analytical techniques were used to characterize the chemical composition and the thickness of the surface oxide on an AlCu2.2 %at alloy sample. ToF-SIMS analyses show that the oxide layer is thinner on the intermetallic particles (IMPs) as compared to the Al matrix. Combined with XPS, analyses reveal that IMPs are covered by aluminium and copper(I) oxide whereas the Al matrix is covered by aluminium oxide. Moreover, metallic copper segregates at the oxide/metal interface on both matrix and IMPs. The heterogeneities at the metal/oxide interfaces suggest that complex galvanic effects could occur between IMP and matrix substrate, and within the IMPs.