Galvanizing Treatment of Aluminum Sacrificial Anode Surface and Its Electrochemical Performance

The surface of Al alloy-based sacrificial anodes were galvanized to different thicknesses, and the electrochemical performance of the anodes were analyzed by polarization testing, EIS and self-discharge method. The polarization curves showed that the corrosion potential of galvanized specimens shifted positively with the increase of zinc coating thickness. The results of EIS showed that the electrochemical activity of the samples increased. The results of self-discharge tests showed that there was little influence of Zn layer on the couple current as time changed, but the change of protection couple current tended to more smooth for anodes with certain thickness of Zn layer. The change of cathodic protection potential with time decreased fast firstly. then tended to be slow and stable at last. The thicker the Zn layer, the more negative the shift degree of cathodic potential.