Study On Formulation And Performance Of A Novel Imidazoline Pickling Inhibitor

Effects of ODD , SDBS, SDS, KI on corrosion behavior for carbon steel are studied by weight-loss experiment,Tafel curves and electrochemical impedance spectrum.A novel acid pickling inhibitor,named MZL-1 is obtained based on the synergic effect of ODD and KI.MZL-1 has excellent efficiency of corrosion inhibition with wider concentration rage,wider temperature rage when the concentration of Fe3+ is below 500ppm.It disperses equably and never delaminates and deposites within the time of acid pickling. The static corrosion rate tor carbon steel is 0.6g-m-2-h-1 and the efficiency of corrosion inhibition is 99.02%;the dynamic corrosion rate is below 4g-m-2-h-1 and corresponding efficiency is 95.61%.The results obtained from Tafel curves show that ODD and KI are mixed inhibitors, which mainly inhibite cathodic process of carbon steel and make the reaction of H+ become slow. The slope of cathodic polarization curve increases and corrosion potential moves nobly,the slope of anodic polarization curve remains unchanged basically.MZL-1 is a mixed inhibitor,which not only affects the cathodic process of H+ but also inhibites the anodic process,making the dissolving process occur qualitative change and the control process become one-electron reaction.The results based on electrochemical impedance spectrum indicate the corrosion process of carbon steel is typical electrochemistry active polarization in hydrochloric acid,ODD and KI.The EIS only behaves capacitive reactance character.KI makes the corrosion process of carbon steel change from single active polarization to active polarization and concentration polarization.The corrosion mechanism of carbon steel in different medium systems is investigated by using Zsimpwin software according to equivalent circuit diagram of electrochemistry. The results indicate that ODD and MZL-1 are typical adsorptive corrosion inhibitors,which make the adsorptive characteristic of A3 carbon steel/hydrochloric acid system change obviously and the control factors of electrode reaction change from potential to potential and fraction of surface coverage.