Corrosion Analysis of Super Duplex Stainless Steel Immersed in Seawater under Different Rotation Speeds

Abstract

This work presents the influence of the turbulent flow in the corrosion of super duplex stainless steel (SDSS) samples immersed in synthetic seawater at room temperature and atmospheric pressure. In order to control the turbulent flow conditions, a rotating cylinder electrode (RCE) was used. Five different rotation rates were studied: 0 (or static conditions), 1000, 2000, 3000, 5000 and 7000 rpm. The electrochemical technique used in the corrosion study was potentiodynamic polarization curve. In addition, Eisenberg equation and analysis of dimensionless numbers were used to determine the limiting current density generated by the cathodic reaction. The results show that of the turbulent flow just has influence in the first rotational speeds of rotating cylinder electrode with an increment in Reynolds number. Cathodic current density obtained at static conditions is higher than densities obtained at 4000, 5000 and 7000 rpm. It is important to point out that at those last rotation speeds; the turbulent flow has not influence on the cathodic current density.