Micro-galvanic corrosion effects on patterned copper-zinc samples during exposure in humidified air containing formic acid
2013 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 160, no 9, C423-C431 p.Article in journal (Refereed) Published
Corrosion in indoor atmospheric environments is often triggered by carboxylic acids, especially at higher relative humidity. Microgalvanic effects can lead to severe corrosion, particularly important in miniature devices with small-sized metallic components. To elucidate the mechanism of micro-galvanic corrosion effects, well-defined zinc-copper patterned samples were investigated during exposure to 100 ppb formic acid (HCOOH) and 80% relative humidity at 20°C. The corrosion effects were monitored quantitatively with in situ infrared absorption spectroscopy, and the corrosion products characterized with scanning electron microscopy, confocal Raman microscopy, and atomic force microscopy. The nature of corrosion on zinc on the patterned samples was compared with that on pure zinc and turned out to result, not only in several times higher corrosion kinetics, but also in different corrosion products with respect to distribution, morphology, and composition. Local electrochemical and chemical gradients across the copper-zinc borders resulted in characteristic hemispherically shaped corrosion products at the zinc-copper junction, and in the formation of zinc formate dihydrate (Zn(HCOO)2 · 2H 2O) and crystalline zinc oxide (ZnO), phases not identified on pure zinc. In all, the micro-galvanic effects on the patterned samples resulted in accelerated corrosion kinetics and in structurally more developed corrosion products.
Place, publisher, year, edition, pages
2013. Vol. 160, no 9, C423-C431 p.
Accelerated corrosion, Atmospheric environment, Chemical gradients, Confocal Raman microscopy, Corrosion kinetics, Corrosion products, Higher relative humidity, Metallic component
Other Chemistry Topics
IdentifiersURN: urn:nbn:se:kth:diva-133863DOI: 10.1149/2.113308jesISI: 000324600600052ScopusID: 2-s2.0-84881512858OAI: oai:DiVA.org:kth-133863DiVA: diva2:663797
FunderSwedish Research Council, 621-2009-3240 348-2008-6078
QC 201311132013-11-132013-11-112014-09-15Bibliographically approved