Electrochemical behaviour and corrosion of MgaY alloys

Highlights ao The corrosion performance of MgaY alloys reported over the largest compositional range to date. ao Quantitative microscopy identified the MgaY intermetallic that formed. ao Quantification of intermetallic electrochemistry via the microcell technique. ao A rational description of the corrosion response for MgaY alloys based on kinetics is given. Corrosion of cast magnesiumayttrium (Y) alloys with systematic Y additions up to a nominal 18wt.% were studied. Corrosion performance was related to the quantitative alloy microstructure and found to increase significantly with the level of alloying and volume fraction of the MgaY intermetallic present. In the alloy microstructures, Mg24Y5 was principally formed; the electrochemistry of which was characterised using the electrochemical microcell method. Electrochemical testing revealed the fundamental corrosion behaviour of MgaY alloys and elucidated the corrosion mechanisms at play.