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TitleLocalised dissolution of iron in buffered and non-buffered chloride containing solutions
Publication TypeJournal Article
Year of Publication2011
AuthorsSoltis, J., Krouse D.P., and Laycock N.
JournalCorrosion Science
Pagination2152 - 2160
Date Published2011
ISSN0010938X (ISSN)
KeywordsA. Iron, B. Polarization, Borate buffer solutions, Buffered solutions, Bulk solutions, C. Pitting corrosion, Chloride concentrations, Chloride solutions, Corrosion products, Dissolution, Electrodes, Hydroxyl anions, Iron, Non-linear, pH value, Pit propagation, Pit solution, Pitting, Pitting corrosion, Pitting potential, Polarization, Pure iron, Sodium chloride, Solution mining, Solution resistance
AbstractPitting corrosion of pure iron was studied by using conventional samples, and artificial pit electrodes. Experiments were conducted in solutions of 0.01, 0.1 and 1moldm-3 NaCl at pH values of 7, 10, 11 and 12; and in borate buffer solutions with the same chloride concentrations and pH 8.7 and 9.2. Four times higher concentration of borate salt was required to reach inhibiting capacity of the hydroxyl anions, as determined via pitting potentials. From measurements of solution resistance, the increase in local conductivity due to dissolved corrosion products exuded from the pit was calculated for each bulk solutions. For the artificial pit electrodes, contribution of the borate species to the internal pit solution conductivity in low chloride solution was associated with the difference between transition potential, ET, values for buffered and non-buffered solutions, and this contribution was also used to explain the non-linear dependence of ET on [Cl-]. Further analysis was conducted using the concept of the critical i.x parameter for stable pit propagation. © 2011 Elsevier Ltd.

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