Effects of Indium on corrosion behavior of Mg-Al-Cu alloy

A series of Mg-Al-Cu-In alloys with different In contents (0-3 wt%) were prepared to investigate the effect of In on corrosion of Mg alloys. The microstructure investigation shows that In does not change the phase constituents of alloys, but reduces Al content in α-Mg and β-phase size of Mg-Al-Cu alloy. The weight loss measurements in NaCl solution at different water temperatures found that the weight loss rates of alloys depend on In addition of alloys and water temperature. Compared to In-free alloy, the weight loss rates of In-bearing alloys are increased significantly. As In addition is 2 wt%, the alloys exhibit the maximum weight loss rate at high water temperature (70 °C and 90 °C). The electrochemical measurements were conducted to investigate the electrochemical behavior of alloys. Reasons concerning the different corrosion behaviors of Mg-Al-Cu-In alloys are discussed.