Effects of trace Ca/Sn addition on corrosion behaviors of biodegradable Mg–4Zn–0.2Mn alloy

Abstract

The effects of alloying elements of Ca/Sn on corrosion behaviors of the as-cast Mg–4Zn–0.2Mn alloy were investigated by immersion tests and electrochemical methods. The results indicated that the average corrosion rate value of the Mg–4Zn–0.2Mn–Ca alloy was ∼ 0.31 mm/year in Hank's physiological solution for 40 days, and corrosion resistance increased for the specimens containing Ca element rather than that containing Sn because of the higher breakdown potential value, lower current density and deactivated corrosion rate, which was ascribed to a formation of the uniformly distributed Mg–Zn–Ca ternary phase. Keywords: Mg–Zn–Mn alloy, Corrosion behaviors, Hank's physiological solution, Electrochemical test