The role of intermetallic particles in localized corrosion of an aluminum alloy studied by SKPFM and integrated AFM/SECM
2008 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 155, no 5, C211-218 p.Article in journal (Refereed) Published
Aluminum alloy EN AW-3003contains a certain amount of micrometer-sized constituent particles and alarge number of nanometer-sized dispersoids. The practical nobility of intermetallicparticles relative to an alloy matrix was evaluated ex situby scanning Kelvin probe force microscopy (SKPFM), and localized corrosioninitiation of the alloy exposed to chloride solutions was studiedin situ by integrated atomic force microscopy (AFM) and scanningelectrochemical microscopy (SECM). The SKPFM results show a higher Voltapotential for the constituent particles than the matrix, and alarger difference for larger particles. In some cases, the boundaryregion between the large constituents and the matrix exhibits aminimum Volta potential. In contrast, a small Volta potential differencewas measured for the particles less than 1 µm. The SECMmapping of the alloy surface in the solution provided evidenceof a cathodic action of some constituent particles and alocal anodic dissolution adjacent to them. Concurrent AFM and SECMimages indicate that only some of the constituents are proneto initiate localized corrosion. Moreover, in situ AFM observations confirmenhanced localized dissolution in the boundary regions, verifying the cathodiccharacter of the constituent particles and a microgalvanic effect onlocalized corrosion. The fine dispersoids of nanometer size seem tohave no effect on the corrosion initiation.
Place, publisher, year, edition, pages
2008. Vol. 155, no 5, C211-218 p.
PROBE FORCE MICROSCOPY; SCANNING KELVIN PROBE; IN-SITU; CHLORIDE SOLUTIONS; MANGANESE-SILICON; AL-ALLOYS; BEHAVIOR; AFM; AA2024-T3; SECM
IdentifiersURN: urn:nbn:se:kth:diva-7858DOI: 10.1149/1.2883737ISI: 000254779700024ScopusID: 2-s2.0-41849083105OAI: oai:DiVA.org:kth-7858DiVA: diva2:13003
QC 20100705. Uppdaterad från Submitted till Published i DiVA 20100705.2007-12-182007-12-182012-03-19Bibliographically approved