Spatial and Local Studies of Magnesium Corrosion using Scanning Electrochemical Microscopy (SECM)

The application of Mg/Mg alloys is restricted by the vulnerability to corrosion. A fundamental understanding of the correlation between microstructure and local electrochemical processes is required to decipher the corrosion mechanisms in Mg/ Mg alloys. In this thesis, scanning electrochemical microscope (SECM) has been employed to locally map the cathodic/anodic sites distributed across corroding Mg/Mg alloy surfaces. A homemade, ion selective micro-electrode (ISME) was fabricated to determine local Mg2+ ion concentrations arising from Mg corrosion. The inferences from the SECM measurements on Mg corrosion were also compared with those from other traditional electrochemical techniques and related to the substrate microstructures.