Corrosion behavior of the second phase in Mg–9Gd–3Y–2Zn–0.5Zr alloy under simulated coastal storage environment

Abstract The Mg–9Gd–3Y–2Zn–0.5Zr alloy was studied for its long-term corrosion behavior in a simulated coastal storage environment. The results show that the Mg12 (Y, Gd) Zn phase in the Mg–9Gd–3Y–2Zn–0.5Zr alloy forms a galvanic couple with α-Mg, and the Mg12 (Y, Gd) Zn phase acts as a cathode to accelerate α-Mg during the corrosion initiation period. The corrosion of the anode is subsequently transformed into corrosive dissolution of the anode. With the dissolution of the Mg12 (Y, Gd) Zn phase, elements such as Gd and Y are gradually distributed into the entire corrosion product layer, improving the protective performance of the corrosion product layer by forming dense Gd2O3 and Y2O3.