Effect of Indium on the Negative Difference Effect for Magnesium Alloy

Abstract

The Mg-xIn (x = 0.5, 1, 1.5 wt.%) alloys exhibit the negative difference effect. This anomalous phenomenon was studied in 0.1 M NaCl solution using galvanostatic polarization testing and real-time hydrogen collection. Strong anomalous hydrogen evolution was observed in all three magnesium alloys, but the rate of hydrogen evolution at different anodic current densities decreased with the increased content of In element. It shows that adding indium to Mg can reduce the negative difference effect of Mg alloy. Assessment of the exchange current density for hydrogen evolution reaction supported the previously-proposed kinetic model. The exchange current density related to the hydrogen evolution reaction decrease with the increased content of In element, indicating the ability of magnesium alloys to support the cathodic reaction is weakened, and In element can effectively reduce the negative difference effect of magnesium alloy.