- Title
- Trends in long-term corrosion of aluminium alloys in marine, industrial and urban environments
- Creator
- Melchers, Robert E.
- Relation
- Annual Conference of the Australasian Corrosion Association 2014: Corrosion and Prevention 2014. Proceedings of the Annual Conference of the Australasian Corrosion Association 2014: Corrosion and Prevention 2014 (Darwin, N.T. 21-24 September 2014)
- Relation
- Funding BodyARCGrant NumberDP140103388 http://purl.org/au-research/grants/arc/DP140103388
- Publisher
- Australasian Corrosion Association
- Resource Type
- conference paper
- Date
- 2014
- Description
- Aluminium alloys have excellent corrosion resistance including in seawater and marine conditions. Herein a wide range of literature data, including in-situ immersion, tidal, coastal atmospheric and industrial exposures is examined. It is shown that while the classical power-law has been assumed, widely, to be valid as a model for the progression of corrosion, in the longer term corrosion of aluminium alloys is nearly always more consistent with the bi-modal model previously proposed only for the corrosion behaviour of steels in seawater and marine conditions, including in the atmosphere. Although aluminium alloys tend to pit rather than to corrode 'uniformly', the bi-modal trend applies irrespectively of whether mass loss, loss of tensile strength or the deepest pits are considered. It is proposed the bi-modal characteristic results from the accumulation of corrosion products causing localised anoxic conditions. These permit a change from predominantly cathodic oxygen reduction to hydrogen ion reduction under anoxic autocatalytic conditions within pits. This mechanism is consistent with established theory for pitting corrosion in aluminium, such as proposed many years ago by Wranglen. It is shown that maximum pit depths for very deep pits tend to follow the Frechet rather than the Gumbel Extreme Value distribution. This is consistent with what has been observed previously for steels.
- Subject
- aluminium; corrosion; long-term; modelling; pitting
- Identifier
- http://hdl.handle.net/1959.13/1294670
- Identifier
- uon:18834
- Identifier
- ISBN:9781634395441
- Language
- eng
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