Establishment of Electrode Potential-composition Plot of Al-Mg-Zn Alloys and Sacrificial Anode Protection Tests

A series of Al-Mg-Zn alloys were prepared by flux melting in the atmosphere. The as-prepared alloys were investigated by electrochemical performance testing and anodic protection experiment. Al-Mg-Zn electrode potential-component ternary plot was established. The results show that when x and y were equal to 0.2～0.6 and 0～0.4 respectively, the corrosion current density and free corrosion potential of alloys were very low, Ecorr was between -1.03 V and -1.25 V(vs.SCE), Jcorr was between 8.7×10-7 A/cm2 and 5.01×10-5 A/cm2. At the same time, Al0.2Mg0.2Zn0.6 and Al0.6Mg0.2Zn0.2 alloys had a good protective effect for Q235 steel in the solution of 3.5% NaCl.