The anomalous alkalinization of the electrolyte during a slight anodic polarization of Mg: A different perspective

To better understand several phenomena during the anodic polarization of Mg, a gel electrolyte (doped with phenolphthalein) was used to avoid the strong convective effects produced by H2 evolution and reveal alkaline zones. Such a methodology is not new but is rarely used and this article does provide new insights about the Mg dissolution, when it is galvanically coupled to AA7075. It has been possible to show that the OH- ions generated during the Mg dissolution are locally neutralized into the electrolyte. On the other hand, the place (and its exceptional characteristics) where the Mg(OH)2 compound is generated during the anodic dissolution of Mg was accurately identified.