Abstract
The effect of sensitisation on the atmospheric corrosion of AA5083 'O' temper was investigated under 0.5 µl NaCl droplets. At chloride deposition densities of 5500±600 μg/cm2 and 2000±200 μg/cm2 sensitisation increased the atmospheric corrosion rate of the alloy in weeklong experiments at 87% RH. Intergranular attack was the main type of corrosion observed in these experiments, in addition to pitting. Regions around pits or IGC sites were observed to become mildly acidic, due to hydrolysis that occurred. Beyond these regions net cathodes areas formed, which were darker and etched in appearance, due to possible increased local alkalinity. The relative size and frequency of these regions that formed also proved to be different in sensitised and as-received samples. The effect of sensitisation to the corrosion rate of the alloy was also more obvious under conditions of lower chloride deposition density. This was shown through a higher intergranular attack on the sensitised alloy surface, relative to minor attack on AA5083 in its 'O' tempered state. Droplet spreading behaviour also seemed to be influenced by the presence of corrosion product at the droplet edge, with the micro-droplets also observed to form around parent droplets.
Original language | English |
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Publication status | Published - 2017 |
Event | Joint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017 - Prague, Czech Republic Duration: 3 Sept 2017 → 7 Sept 2017 |
Conference
Conference | Joint European Corrosion Congress 2017, EUROCORR 2017 and 20th International Corrosion Congress and Process Safety Congress 2017 |
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Country/Territory | Czech Republic |
City | Prague |
Period | 3/09/17 → 7/09/17 |
Bibliographical note
Publisher Copyright:© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. All rights reserved.
Keywords
- Deposition density
- Intergranular corrosion
- NaCl droplets
- Sensitisation
ASJC Scopus subject areas
- Colloid and Surface Chemistry
- Surfaces and Interfaces