Electrochemical Property of Two Al-Zn-In Aluminum Alloy Sacrificial Anodes Used for Conservation of Shipwreck and Its Influence Factors

In terms of chemical composition, microstructure, corrosion morphology and self-corrosion behavior, the main reasons for the difference in self-discharge performance of two Al-Zn-In sacrificial anodes used for the cathodic protection of the metal frame of an ancient shipwreck in-situ protection were discussed. The results show that: compared with No. 2 aluminum alloy sacrificial anode, No. 1 aluminum alloy sacrificial anode had higher current efficiency. The corrosion rate of aluminum alloy and the shedding behavior of surface corrosion products would not significantly affect the self-discharge performance of the two sacrificial anodes. The obvious grain shedding of No. 2 aluminum alloy sacrificial anode during the corrosion process was the main reason for the obvious decline of its self-discharge performance. This phenomenon might be related to the existence of Ti-rich deposition phases at the grain boundaries.