Influence of Mn and Zr on the corrosion of al-free Mg alloys: Part 2-impact of Mn and Zr on Mg alloy electrochemistry and corrosion

A total of 47 alloys were produced to explore the changes in electrochemical and corrosion behavior of binary and ternary Mn- and Zr-containing Mg alloys-in the absence of Al. Up to ~2 wt% Mn was found to slightly reduce cathodic kinetics, while Zr in solid solution increased anodic reaction kinetics. We demonstrate that Zr is an efficient "activator" of Mg, which has not been explicitly shown previously. When Mn and Zr are both added to Mg, there can be an optimized combination/ interaction where Mn with Zr works in conjunction to moderate the corrosion rate compared to an Mg-alloy with either Zr or Mn as singular additions. This has ramifications in emerging Al-free Mg alloys