Study On Corrosion Inhibitor Of Carbon Steel In 3% Sodium Chlorrde Solution

Carbon steel is the most widely used steel in industry. At recent, seawater always was used of industry circulating water, however, seawater has strong corrosive action on metals. Corrosion has inflicted considerable loss to our economy.So it is very important to studying the corrosion inhibitor in chlorine ion medium.Some corrosion inhibitors of 20# carbon steel were studied with electric-chemical technique. At 30℃, Tafel polarize curve and AC impedance were used to study the inhibition of Na2MoO4, NaGl, Sodium benzoate, ZnSO4 and SDBS roughly. Then Na2MoO4 and SDBS were chosen to study the synergistic effect of Corrosion inhibition. In the complex system of adding different concentrations of zinc sulfate, the inhibition effect was inspected to these three ingredients as the prescription of inhibitiort.The results show that: In 3% Sodium chloride solution, carbon steel was easily corroded and the pitting corrosion occurred on carbon steel surface because of the existence of Cl- in corrosive solution.Individual use of Na2MoO4 can be a very good carbon steel corrosion inhibitor. It is an anode inhibitor that has the best corrosion at the concentration of 0.6g/L. The adsorption of Na2MoO4 on the carbon steel surface from 3 %NaCl solution almost obeyed the Langmuir adsorption isotherm .It was a spontaneous, exothermic process accompanied by a decrease in entropy. SDBS acts as an anodic inhibitor for carbon steel in 3%NaCl solution. The adsorption of SDBS on the carbon steel surface from 3 %NaCl solution almost obeyed the Langmuir adsorption isotherm.The adsorption of SDBS onto carbon steel surface in 3%NaCl solution was a spontaneous, exothermic process accompanied by a decrease in entropy. Na2MoO4 and SDBS have good synergy inhibition effect. The corrosion inhibition efficiency can be achieved around 80% when the concentration rate is 0.1:0.8. Na2MoO4, SDBS and zinc sulfate has the corrosion synergy. Na2MoO4 of 50 mg/L, SDBS of 80 mg/L and zinc sulfate of 20 mg/L have matching corrosion inhibition to carbon steel and the inhibition efficiency can be achieved 85%.In this paper, the formulation of the corrosion mechanism was discussed. The compound is a mixed inhibitor that can protect the steel surface of the membrane, thereby inhibiting the carbon steel corrosion. Protective membrane was composed of sedimentation and adsorption film together.