Improvement of Corrosion Resistance by Zn Addition to Mg Alloy Containing Impurity Ni

Abstract

There is the deleterious influence of corrosion resistance of Mg alloy by contaminant of impurity element Ni during Mg recycling. Mg2Ni precipitates trigger the galvanic corrosion with Mg matrix phase. Zn addition into Mg alloy may reduce the detrimental impact of impurities because a small amount of Ni element is dissolved into Mg-Zn intermetallic phase. Therefore, the microstructure and corrosion behavior were investigated by changing the amount of Zn in Mg alloy with a trace amount of Ni. From the results of the microstructural observation, Ni element existed in MgZn2 intermetallic phase when the Zn content exceeded 6 mass%, to change the existing state of Ni whereas Mg2Ni phase was dispersed in Mg-Zn alloy with a few percent of Zn.