Role of hydrogen evolution rate in determining the corrosion rate of extruded Mg-5Sn-(1-4Â wt%)Zn alloys

The corrosion behavior of as-extruded Mg-5Sn-(1-4)Zn (in wt%) alloys in a 0.6 M NaCl solution were investigated using an immersion test, a polarization test, and a zero resistance ammeter technique, and the corrosion properties of the alloys were discussed in consideration of the microstructure. The immersion test showed that the Mg-5Sn-2Zn alloy exhibited the lowest dissolution rate among the alloys, and further addition of Zn increased the corrosion rate. The electrochemical test results revealed that the overall corrosion rate of the passivated Mg-5Sn-(1-4)Zn alloys showed a strong correlation with the H2 evolution rate rather than the stability of the passivity.