Electrochemical Behavior of Precipitation Hardened Mg‐5Sn‐5Zn and Mg‐5Sn‐5Al Alloys

The repassivation behavior of artificially aged Mg‐5Sn‐5Zn and Mg‐5Sn‐5Al alloy was studied with cyclic potentiodynamic polarization (CPDP) in 3.5% NaCl solutions. Specifically, the intent with this study was to get a better understanding of the influence of alloy microstructures, including the size distribution of the Mg 2 Sn phase, on corrosion behavior. In this study, solutionized condition exhibits higher corrosion resistance in both alloys. With increasing ageing times, the corrosion resistance was reduced primarily due to the formation of secondary phases, its volume fraction and sizes. XPS analysis reveals the oxide/hydroxide products of MgO and Mg (OH) 2 , in this passive layer. The existence of this layer is correlated with electrochemical impedance spectroscopy (EIS) and SEM observation.