Influence of silicon on the corrosion behaviour of Al–Zn–In–Mg–Ti sacrificial anode

The influence of Si on the corrosion behaviour of Al–5Zn–0.03In–1Mg–0.05Ti (wt.%) alloy was investigated by the microstructure observation and electrochemical measurements in order to improve its corrosion non-uniform and electrochemical properties. The main precipitates in Al–5Zn–0.03In–1Mg–0.05Ti–0.1Si (wt.%) alloy is Mg2Si phase, which decrease the galvanic corrosion because the potential difference between Mg2Si and a-Al is smaller than that between MgZn2 and a-Al. The addition of Si improves the corrosion uniformity of the anode due to the fine equiaxed grains and grain boundaries where Mg2Si particles uniformly distributed. The results indicate that the microstructure, electrochemical characteristics and corrosion uniformity can be improved significantly after adding 0.1 wt.% Si into Al–5Zn–0.03In–1Mg–0.05Ti (wt.%) alloy.

► Effects of Si on corrosion behaviour of Al–Zn–In–Mg–Ti anode.
► Changes in microstructure after adding Si in Al–Zn–In–Mg–Ti anode.
► Identification of precipitates in Al–Zn–In–Mg–Ti–Si alloy.
► Manufacture of simulated bulk α-Al, Mg2Si and Mg2Zn alloys.
► Corrosion properties of simulated bulk α-Al, Mg2Si and Mg2Zn alloys.