The Corrosion Behavior of High Purity Mg According to Process History

This study paid attention to the big difference between the corrosion rates of permanent mold cast and hot-extruded pure Mg. Fe existed as different state according to process history, which affected the corrosion behavior of pure Mg largely. The corrosion rate of high purity Mg was measured extremely low when Fe was dissolved into the matrix as a solid solution while it increased dramatically when Fe was precipitated as a second phase. The precipitation behavior of the second phase containing Fe was affected by other impurities as much as thermal history, which affected the corrosion behavior of high purity Mg. It is suggested from this study that the tolerance limit of Fe is strongly dependent on the content of Fe, the sort and content of other impurities and process history, which should be considered to design the composition and processing route of high corrosion-resistant Mg alloy.