Corrosion potential and breakdown potential distributions for stainless steels in seawater
- Politecnico di Milano (Italy)
- ITM-CNR, Milano (Italy)
The definition of corrosion potential was examined in relation to stainless steels in seawater. The experimental investigation was extended to include austenitic, ferritic and superaustenitic stainless steels. From each material, between 30 and 100 specimens were taken for a total of over 1,000. Measurements of the corrosion potentials of specimens of different sizes and under different exposure conditions were carried out as well as those of the breakdown potentials in cells that could contain up to 100 specimens and also measurements on galvanic couples. All the tests were performed with natural seawater in experiments lasting over a period from 1 to 18 months. The results obtained have shown that: The corrosion potentials of stainless steel in seawater are dispersed in a wide range; The dispersion is not only attributable to fluctuations of the environmental characteristics or to differences between the specimens of the same steel but is an intrinsic characteristic of the specific corrosion system; The distribution of the corrosion potentials measured on the same specimen at different times is similar to the distribution of the corrosion potentials of different specimens, of the same sample, measured at the same time. The distribution of corrosion potentials, like the distribution of breakdown potentials, is affected by the size of the specimens, the exposure conditions and whether forms of localized corrosions are present. A peculiar role in the corrosion potential distribution appears to be played by the galvanic coupling between the surface of the stainless steel and predetermined non-uniform areas such as the edges of the specimens or not predetermined like the areas of development of the localized attack or fluctuating in space and time like the areas of potential or incipient attack.
- OSTI ID:
- 379691
- Report Number(s):
- CONF-960389-; TRN: IM9644%%147
- Resource Relation:
- Conference: National Association of Corrosion Engineers (NACE) annual corrosion conference and exposition: water and waste water industries, Denver, CO (United States), 24-29 Mar 1996; Other Information: PBD: 1996; Related Information: Is Part Of Corrosion/96 conference papers; PB: [6615] p.
- Country of Publication:
- United States
- Language:
- English
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