Effect of Rotation Rate in the Electrochemical Behavior of Aluminum Anodic Alloys

摘要

Cathodic protection of steel structures immersed in marine media uses sacrificial anodes of Zinc (Zn) or Aluminum (Al) alloys. The flow conditions, in which they are operating, have an injurious effect accelerating the problems of degradation of these materials. In this work electrochemical tests were carried out in Al-Zn-Mg anodic alloys. Mg was used in different concentrations ranging from 5.5 to 8.5 at.% maintaining constant the amount of Zn in 5.3 at. %. In order to get the controlled flow condition a Rotating Cylinder Electrode (RCE) was used. Corrosion potential (E_(corr)), Linear Polarization Resistance (Rp), Polarization Curves and Electrochemical Impedance Spectroscopy (EIS) were carried out to get the electrochemical behavior of the cylindrical working electrodes. The effect of the flow conditions indicated a diminution of Rp values and therefore increases the corrosion rate.