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The role of solution chemistry on the Corrosion of Copper in Tap Water: The effect of dissolved silica on uniform and localized attack
Author(s) -
Alhajji J. N.,
Reda M. R.
Publication year - 1996
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.19960471005
Subject(s) - dissolved silica , chemistry , copper , corrosion , sulfate , inorganic chemistry , bicarbonate , tap water , silica gel , dissolved organic carbon , dissolution , environmental chemistry , chromatography , organic chemistry , environmental engineering , engineering
Pitting of copper pipes was stimulated in the laboratory in synthetic tap waters with various water chemistries under stagnant conditions at room temperature. The primary interest was the effect of dissolved silica on uniform and localized attack. Long term experiments were conducted by immersion tests over eight months period. Short term tests were conducted using cyclic potentiodynamic tests. It is found that the effect of dissolved silica is similar to the behavior of an anodic inhibitor. The corrosion mechanism of copper in the presence of dissolved silica seems to proceed by a two step mechanism. An initial activation control corrosion reaction for a period of two months and a final diffusion control reaction with respect to dissolved silica. The effect of the ratio of dissolved silica to calcium ion concentration seems to indicate the predominate effect of dissolved silica. The effect of the ratio of dissolved silica to carbonate ion concentration seems to indicate the fact that increasing dissolved silica and/or decreasing bicarbonate ion concentration intensifies the corrosion rate. The effect of the ratio of dissolved silica to sulfate ion concentration seems to indicate the predominate effect of dissolved silica.