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How does/can wet carbon dioxide lead to corrosion problem in iron-containing metals? View All

14 years ago - 9 months left to answer. - 2 responses - Report Abuse
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Carbon dioxide reacts with water: CO2 + H2O --> HCO3- + H+ As the concentration of CO2 increases, so does the concentration of the H+ ion. This ion then react with Fe in metals: Fe + 2H+ --> 2H (atom) + Fe2+ As corrosion proceeds, the ferrous ions produced react with the bicarbonate ions to form ferrous carbonate which precipitated as a scale.

14 years ago


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CO2 corrosion is a complex issue 'cause even if it's weak acid it will cause high corrosion rate on Steel (other alloy like stainless steel and nickel alloya are not affected by CO2 corrosion)
this is due to the fact that ,as someone else correctly said, the Hydrogen from
H2CO3 --- > 2H+ + CO3--
will corrode steel

2H+ + 2e- ----> H2

Fe ----> Fe2+ + 2e-

but there is also the direct reduction of

H2CO3 +2e- ----> H2 + CO3--

that is a cathodic reaction that increase the overall corrosion rate.

12 years ago


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