Two years pitting corrosion of AA5005-H34 aluminium alloy immersed in natural seawater: data interpretation

ABSTRACT

This paper reports pitting corrosion loss data of AA5005-H34 aluminium alloy immersed in natural seawater for up to 2 years. It is shown that the data for mass loss, maximum pit depth and the average value of 15 deepest pits as a function of exposure time are not closely consistent with the classical power-law function. Instead, the data show a greater affinity to the early part of a bi-modal trend. The uncertainty of the pit depth data was analysed using extreme value theory. The results are that scatter in the data sets increases with exposure time. This is considered to be the result of the pit depth data population being non-homogeneous, characterised by a mixture of deep pits with differing pitting morphologies. The results of this study suggest that longer-term data and homogeneous data population are likely to be more reliable for future corrosion loss prediction purposes.

KEYWORDS:

• Aluminium alloys
• pitting corrosion
• extreme value analysis

Acknowledgements

The authors acknowledge the financial support provided by the University of Newcastle and the Australian Research Council under grant DP14010338. The authors also thank the help of the technical support from the Central Scientific Service of The University of Newcastle.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by The University of Newcastle Australia; The Australian Research Council [grant number DP14010338].