Corrosion of Anodically and Cathodically Polarized Magnesium in Aqueous Media

The effect of current density, p H, and temperature on the anodic behavior, cathodic behavior, and corrosion of magnesium in aqueous solutions has been studied. A tentative mechanism for the anodic oxidation of magnesium is postulated. Local corrosion and/or undermining of metallic magnesium at the anode are appreciable and may, in fact, account for the observed low anodic current efficiencies of magnesium. An intergranular type of corrosion occurs at cathodically polarized magnesium at elevated temperatures. A hydrogen embrittlement theory is proposed to explain intergranular cathodic corrosion.