Improving corrosion resistance of high strength Mg-Zn-Y alloy through Ca addition

ABSTRACT High-strength Mg-Zn-Y alloy with a long-period stacking ordered (LPSO) phase was chosen as the base alloy, and different Ca were added to it. The phase component and microstructure of the alloys were examined using diffraction of X-rays (XRD) and scanning electron microscopy (SEM). A new phase, Ca2Mg6Zn3, was found to be formed by the addition of Ca. The hydrogen evolution corrosion method and an electrochemical test showed that the amount of hydrogen evolution without Ca addition was twice that with Ca addition. The corrosion resistance of the magnesium alloy improved when the amount of Ca added was. In order to understand the dynamic corrosion process, we soaked Mg97Zn1Y2-X wt-% Ca (X = 0, 0.1, 0.3, 0.6, 1) alloy in 3.5 wt-% NaCl solution for 2, 6, 12 h. It was observed that with an increase in the Ca content, the degree of corrosion of the alloy gradually decreased, and the amount of granular corrosion products covering the alloy’s surface also decreased.