Corrosion characteristics of pure magnesium refined by vacuum distillation

Abstract

Relation between the amount of refined pure magnesium, impurities in the refined magnesium and purification time has been investigated for vacuum distilled magnesium alloys AM100A and AM60B. Corrosion characteristics of pure magnesium which was refined and then remelted in a vacuum high frequency induction furnace were investigated by means of a salt spray test and an electrochemical method. The extent of purification, defined by the quantity ratio of refined magnesium to alloy used increases linearly with increasing purification time, though purification rate is higher in alloy AM100A than in alloy AM60B. Zinc content in the refined magnesium decreases with purification time. The corrosion loss of the remelted pure magnesium in salt spray test, is as low as that of high purity commercial magnesium alloys. Both the amount of impurities and the current density of cathodic part of polarization curve are greater in the commercially pure magnesium than in the refined pure magnesium.