The effects of lanthanum on microstructure and electrochemical properties of Al–Zn–In based sacrificial anode alloys

In order to improve the non-uniform corrosion of Al–0.5Zn–0.03In–1Mg–0.05Ti alloys, Al–5Zn–0.03In–1Mg–0.05Ti–xLa (x = 0.3, 0.5 and 0.7 wt.%) alloys were developed. Microstructures and electrochemical properties of the alloys were investigated. The results show that the optimal microstructures and electrochemical properties are obtained in Al–5Zn–0.03In–1Mg–0.05Ti–0.5La alloy. The main precipitate phase is Al2LaZn2 particles. The excellent electrochemical properties of Al–5Zn–0.03In–1Mg–0.05Ti–0.5La alloy is mainly attributed to fine grains and grain boundaries containing fine Al2LaZn2 precipitates. At the same time the fine grains can improve the non-uniform corrosion of Al–0.5Zn–0.03In–1Mg–0.05Ti alloy.