An Electrochemical Study to Evaluate the Effect of Calcium Nitrite Inhibitor to Mitigate the Corrosion of Reinforcement in Sodium Chloride Contaminated Ca(OH)2Solution

The effect of calcium nitrite (Ca(NO 2 ) 2 ) was assessed by electrochemical means such as open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic studies in saturated Ca(OH) 2 solution contaminated with 0.99 and 7.91 g/L NaCl. The preliminary results of OCP showed that the potential is shifted towards positive (noble) side as content of inhibitor increased. The EIS results indicate that Ca(NO 2 ) 2 works effectively in reduction and initiation of corrosion of steel rebar in NaCl contaminated Ca(OH) 2 solution. Potentiodynamic studies revealed the pitting tendency of steel rebar exposed in 0.99 g/L NaCl at [Cl − /NO2-] = 1.2 attributed to low conductivity of passive film which causes interference for Cl − ions attack during anodic polarization. The 85.75% efficiency is found in 0.99 g/L at [Cl − /NO2-] = 1.2. The Ca(NO 2 ) 2 inhibitor transformed the unstable iron oxides/hydroxides into stable and protective oxides/hydroxides due to its strong oxidizing nature. Therefore, this inhibitor is sufficiently and significantly reducing the corrosion of steel rebar at even its low concentration with 0.99 and 7.91 g/L NaCl solution.