The influence of SO2 on the corrosion of Mg and Mg-Al alloys
2015 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 162, no 6, C260-C269 p.Article in journal (Refereed) Published
The SO2-induced atmospheric corrosion of some magnesium-aluminum (Mg-Al) alloys, including Mg alloy AZ91D, and commercially pure Mg (CP Mg) was investigated using well-controlled laboratory exposures and included real-time measurements of SO2 deposition. The influence of SO2 concentration, alloy composition, humidity, and ppb level additions of O-3 or NO2 on the rate of SO2 deposition was investigated. SO2 accelerates the corrosion of Mg and Mg alloys causing localized corrosion, MgSO(3)6H(2)O being the dominant corrosion product. At 60% RH, traces of O-3 or NO2 strongly increased both the SO2 deposition and the corrosion rate. The rate of SO2 deposition was strongly dependent on humidity; at 70% RH and higher the SO2 deposition rate was very rapid and constant in time while it was transient below 50% RH. At 60% RH, a change from transient to rapid, steady-state, SO2 deposition occurred. The sudden activation is explained by the onset of electrochemical corrosion. The activation behavior was shown to depend on SO2 concentration, the thickness of the surface film and by the presence of ambient O-2. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited.
Place, publisher, year, edition, pages
2015. Vol. 162, no 6, C260-C269 p.
Alloys, Aluminum, Aluminum coatings, Atmospheric corrosion, Atmospheric humidity, Chemical activation, Corrosion, Corrosion rate, Deposition, Electrochemical corrosion, Activation behavior, Alloy compositions, Controlled laboratories, Corrosion products, Localized corrosion, Mg-Al alloys, Real time measurements, Surface films
Other Chemistry Topics
IdentifiersURN: urn:nbn:se:kth:diva-167008DOI: 10.1149/2.0801506jesISI: 000353009300055ScopusID: 2-s2.0-84928313963OAI: oai:DiVA.org:kth-167008DiVA: diva2:813433
FunderSwedish Foundation for Strategic Research
QC 201505222015-05-222015-05-212015-08-05Bibliographically approved