Corrosion Behavior of Magnesium Alloys Containing Sn and Zn

The microstructures and corrosion behaviors of the magnesium alloys containing Sn and Zn are evaluated systematically. The as-extruded TZ alloys show a typical equi-axed grain structures formed by dynamic recrystallization. The fine particles of Mg2Sn phase are observed in grain interior and along grain boundaries. The corrosion potential measured by potentiodynamic test increases with increase of Zn content. The current density at cathodic region increases with increase of Zn content, which means that the hydrogen evolution rate increases with increase of Zn content. It seems that the corrosion behaviors of as-extruded TZ alloys will be affected by the amount of Sn and Zn dissolved into the α-Mg phase and the fraction of Mg2Sn phase.