Performance Evaluation of Al-Zn-Bi Sacrificial Anode in a Marine Environment

This article examines the influence of 0.2 wt% bismuth addition on the corrosion behavior of Al-4.2 wt% Zn sacrificial anode in artificial seawater. Corrosion behavior was assessed by electrochemical methods such as open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. Approximately 400 mV potential difference between anode and steel confirmed the effective protection capacity of the anode. The absence of an inductive loop at low frequency of the impedance spectra and a decrease in charge transfer resistance suggested that the addition of Bi could suppress hydrogen evolution, confirming uniform dissolution of the sacrificial anode.