The Synergistic Effect of Iodide and Sodium Nitrite on the Corrosion Inhibition of Mild Steel in Bicarbonate-Chloride Solution.
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ABSTRACT: The effect of potassium iodide (KI) and sodium nitrite (NaNO₂ inhibitor on the corrosion inhibition of mild steel in chloride bicarbonate solution has been studied using electrochemical techniques. Potentiodynamic polarisation data suggest that, when used in combination, KI and NaNO₂ function together to inhibit reactions at both the anode and the cathode, but predominantly anodic. KI/NO₂- concentration ratios varied from 2:1 to 2:5; inhibition efficiency was optimized for a ratio of 1:1. The surface morphology and corrosion products were analysed using scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The latter shows that the addition of I- to NO₂ facilitates the formation of a passivating oxide (γ-Fe₂O₃) as compared to NO₂- alone, decreasing the rate of metal dissolution observed in electrochemical testing. The synergistic effect of KI/NO₂- inhibition was enhanced under the dynamic conditions associated with testing in a rotating disc electrode.
SUBMITTER: Eyu GD
PROVIDER: S-EPMC5457186 | biostudies-other | 2016 Oct
REPOSITORIES: biostudies-other
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