Microstructure effects on the electrochemical corrosion properties of Mg – 4.1% Ga – 2.2% Hg alloy as the anode for seawater-activated batteries

Mg–Ga–Hg alloy is a new material with special electrochemical corrosion properties that make it ideal for use in seawater-activated battery anodes. The effects of microstructure and phase transformation on the electrochemical properties of the Mg – 4.1% Ga – 2.2% Hg alloy were studied and compared with Mg–Al system alloys. The results show that the Mg – 4.1% Ga – 2.2% Hg alloy, when used as an anode, has an appropriate corrosion potential in a half-cell test and superior electrochemical properties in a single cell assembled with CuCl. The Mg3Hg and Mg21Hg5Ga3 phases of the alloy influence its corrosion behaviour and provide a steady corrosion potential during the discharge process.

Research highlights
► We compared the electrochemical properties of Mg–Ga–Hg alloy with AZ system alloys.
► We studied the effects of phases on the electrochemical properties of Mg–Ga–Hg alloy.
► We discussed the relation between the phases with electrochemical properties.
► We studied the phase transformation of Mg3Hg and Mg21Ga5Hg3.