Influence of turbulent flow on the corrosion of Al‐Zn‐Mg galvanic anode in artificial seawater media

Abstract

AbstractThe effect of hydrodynamics on the corrosion of Al(14 wt%)‐Zn(8 wt%)‐Mg alloy in artificial seawater media at room temperature was studied in a rotating cylinder electrode (RCE) system under turbulent flow conditions. Five different rotation rates were studied: 100, 1000, 3000, 5000, and 7000 rpm. The corrosion rates were measured by electrochemical impedance spectroscopy (EIS). For the system studied, the steady‐state corrosion potential increased with increase in rotation rate. The effect of increasing the rotation rate is to increase the availability of oxygen at the surface, which in turn will polarize the corrosion reaction in the more noble direction. The corrosion rate also increases with increase in RCE rotation rate. This reflects the fact that the rate of corrosion is controlled, at least in part, by the rate of mass transfer. In this case, the effect of increase in the rotation rate on the corrosion rate is to increase the interfacial concentration of the reactant (oxygen).