Determination of corrosion protection current density requirement of zinc sacrificial anode for corrosion protection of AA5083-H321 in seawater

Abstract In this study, the current density requirements of zinc sacrificial anode for corrosion protection of AA5083-H321 aluminum hull for the ship was determined through various electrochemical tests. Surface observation and chemical composition analysis were performed after the galvanostatic test for various current density requirements determined by the cathodic polarization experiment. As a result, the most appropriate current density requirement range was determined as 3.7 x 10-6 ∼ 5.8 x 10-6 A/cm2. Excessive current density over 7.6 x 10-6 A/cm2 caused local surface damage due to the effect of Mg-rich and Fe-rich intermetallic phases. In addition, the self-consumption of zinc sacrificial anode was determined through Tafel's extrapolation method.