The Corrosion Behavior of Mg5Y in Nominally Distilled Water

This paper studies the macro and micro corrosion of Mg5Y in nominally distilled water. The Y-containing corrosion product film formed on the alloy surface provides some protection for the Mg matrix to the galvanic corrosion caused by Y-containing second-phase particles. In some cases, there is no corrosion of the matrix surrounding most of the second phase particles. However, about 2% of the second-phase particles in the as-cast Mg5Y causes micro-galvanic corrosion, resulting in bump' or volcano' shaped corrosion product deposit. These active particles' cannot be significantly reduced by solution-heat-treatment.