Corrosion Behavior of Mg-Zn-Y Alloy with Long-period Stacking Ordered Structures

Mg-Zn-Y alloys with long-period stacking ordered structures were prepared by an ingot casting method. The corrosion performance of Mg-Zn-Y alloys was studied by combining gas-collecting test, immersion test and electrochemical measurements in order to determine the corrosion rate and mechanism of the alloys. The results showed that the volume fraction of Mg(12)YZn phase increased and the shape of the Mg(12)YZn phase changed from discontinuous to continuous net-like with increasing Zn and Y content. The corrosion rate of the alloys greatly depended on the distribution and volume fraction of the Mg(12)YZn phase. Corrosion products appeared at the junction of Mg phase and Mg(12)YZn phase, indicating that the Mg(12)YZn phase accelerated galvanic corrosion of Mg matrix. Mg(97)Zn1Y2 alloy shows the lowest corrosion rate due to the continuous distribution of Mg(12)YZn phase.