In situ studies of the initiation and propagation of filiform corrosion on aluminum
2004 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 151, no 7, p. B440-B445Article in journal (Refereed) Published
Abstract [en]
We have investigated the initiation and propagation of filiform corrosion on coated aluminum surfaces using a new experimental set-up for in situ Fourier transform infrared (FTIR) microspectroscopy and the scanning Kelvin probe. During the initiation partially hydrolyzed aluminum chloride was formed in a defect on the coated surface. The conditions in the defect resembled the environment that is found in growing pits with low pH and high chloride concentration close to the coating interface. This weakened the adhesion of the organic coating and initiated the formation of a filament. The movement .of the active head was followed with in situ FTIR microspectroscopy in humid air using the characteristic IR band around 2500 cm-1 from Al(H 2O)6 3+. This band is present in spectra from partially hydrolyzed aluminum chloride, which was found in the head during propagation of the filament. The absorption of water in the hygroscopic corrosion products in the head of the filament was followed by measuring the changes in the intensity of the Al(H2O)6 3+ band during variations in the relative humidity. The hygroscopic properties of the aluminum hydroxy chloride salts formed in the head have important consequences for filiform corrosion, especially concerning the influence of climatic parameters such as the relative humidity and the effect of wet/dry transitions on the propagation of filiform corrosion.
Place, publisher, year, edition, pages
Electrochemical Society Inc. , 2004. Vol. 151, no 7, p. B440-B445
Keywords [en]
Aluminum, Atmospheric humidity, Cathodes, Crack initiation, Crack propagation, Electrodeposition, Fourier transform infrared spectroscopy, Infrared radiation, Mapping, pH effects, Polyesters, Reduction, Climatic parameters, Corrosion products, Filiform corrosion, Microspectroscopy, Corrosion
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:ri:diva-40447DOI: 10.1149/1.1760577Scopus ID: 2-s2.0-3242723478OAI: oai:DiVA.org:ri-40447DiVA, id: diva2:1361010
2019-10-152019-10-152023-05-26Bibliographically approved