Electrochemical Study of Super Duplex Stainless Steel in Synthetic Seawater Under Turbulent Flow Conditions

摘要

This work presents the study of the effects that the electrolyte and the turbulent flow have on the electrochemical kinetic of the super duplex stainless steel (SDSS) immersed in synthetic seawater at room temperature, atmospheric pressure under static and turbulent flow conditions. In order to control the hydrodynamic conditions, a rotating cylinder electrode was used (RCE) at four rotation rate (1000, 3000, 5000 y 7000 rpm). A typical three-electrode electrochemical cell was used. Cylindrical working electrodes made of SDSS were used in all experiments as working electrode, sintered graphite bar as auxiliary electrode and a saturated calomel electrode as reference. In order to analysis the corrosion phenomenon, the technique electrochemical impedance spectroscopy was used during 24 hours of the exposure time. According to the impedance technique, the corrosion rate decreased as the exposure time in seawater increased. In addition, the effect of the turbulent flow on corrosion process was really negligible. On the other hand, it is important to point out that the oxygen diffusion was the limiting process in the SDSS corrosion.