Spatially-resolved imaging of concentration distributions on corroding magnesium-based materials exposed to aqueous environments by SECM

The spatial resolution of Mg2 + release from magnesium and its alloys during exposure to aqueous environments has been imaged using a new, solid contact, micropipette-based magnesium-ion selective electrode employed as potentiometric tip in SECM. The detection of metal dissolution is a crucial factor to detect the local microelectrodes established on the surface of the metal, and distinguish the processes related to anodic and cathodic half-cell reactions. Concentration distribution images have been obtained for the magnesium-based alloy AZ63 when galvanically coupled to pure iron during exposure to 1 mM NaCl solution.

► Fabrication of a solid contact micropipette-based magnesium ion-selective electrode is described. ► This Mg2 +-ISME can be used as potentiometric tip in scanning electrochemical microscopy (SECM). ► Micro-spatial distribution of Mg2 + ions from a corroding metal source in aqueous environments is monitored.