The influence of zirconium additions on the corrosion of magnesium

• The morphology of the Zr present in the Mg–Zr alloys affects the extent and mode of corrosion.
• Zr dissolved in solid solution in Mg increases the anodic reaction kinetics.
• A greater amount of Zr particles embedded in the Mg matrix increase the cathodic reaction kinetics.
• There are more complex interactions that occur in ternary (and higher order) Mg alloys with Zr.

Sixteen custom binary Mg–Zr alloys and four commercial Zr-containing Mg-alloys were used to investigate the role of Zr on the corrosion of Mg. Mg–Zr alloys were manufactured with a range of different Zr concentrations. It was observed that the Mg–Zr alloys with a smaller mean Zr particle size had more Zr dissolved in solid solution. Both the Zr in solid solution and in metallic particle form were observed to have a deleterious effect on the corrosion rate of Mg. However, this deleterious effect is less pronounced to effect in alloys with multiple alloying additions.