Electrochemical impedance spectroscopic analysis of activation of Al–Zn alloy sacrificial anode by RuO2 catalytic coating

The uniform surface activation characteristics of RuO2-coated Al–Zn alloy sacrificial anodes were studied in the present work. Electrochemical impedance spectroscopic and SEM/EDAX analyses were carried out to evaluate the galvanic dissolution characteristics of the anodes. The conventional electrochemical methods were also followed. Persistence and retention of catalytic RuO2 on the anode surface even after a large extent of galvanic dissolution of the anode surface was confirmed based on the EDAX spectroscopy. The anodes showed the same polarization performances even after the anodes were disintegrated to one-third of its original size, revealing the sustained catalytic activity of RuO2