Corrosion inhibition of carbon steel in NaCl solution Using a mixture of alkanol amine and calcium nitrite: Electrochemical and microscopic evaluation

The corrosion inhibition properties of carbon steel in 3.50 % NaCl corrosion solution were studied by using a compound rust inhibitor composed of alkanol amine and calcium nitrate. The electrochemical impedance spectrum and surface microscopic tests on steel corrosion were carried out under the condition of 3.500 % NaCl corrosion solution, and the AC impedance spectrum curve and microscopic morphology of different proportion of rust inhibitors (alkanol amines, calcium nitrite) on steel corrosion in concrete were obtained. The influence of composite rust inhibitors on steel corrosion process was analyzed. The results show that the composite rust inhibitor composed of 0.50 % alcoholamine and 0.50 % calcium nitrite can prolong the time of steel corrosion and decrease the corrosion rate, in the same environment, the corrosion rate of the steel bar is only 1.27 mm year⁻¹, and the corrosion inhibition efficiency (η) is 97.8 %. Comparing the microstructure of each group, it was found that the passivation film on the surface of the steel bar with the composite rust inhibitor was dense, and no rust spots were found, which protected the steel bar well and achieved the effect of rust inhibition.