Codeposited Zn-Mg coating with improved mechanical and anticorrosion properties

► Zn-Mg coating was prepared by magnetron co-sputtering method. ► The microhardness of Zn-Mg coating is higher than that of Zn coating. ► The anticorrosion property of Zn coating was improved by the addition of Mg. ► Mg facilitates the formation of a corrosion product Zn5(OH)8Cl2H2O. ► This layer of corrosion product shows behavior of a passive film.