한국주조공학회

In the present study, effects of an addition of Sn on the microstructure and corrosion behavior were investigated in Mg-4%Zn-(0- 3)%Sn casting alloys. With an increase in the Sn content, the α-(Mg) dendritic cell size was reduced, whereas the total amount of precipitates increased due to the formation of the Mg2Sn phase. It was found in immersion and electrochemical corrosion tests that the addition of Sn has a detrimental effect on the corrosion resistance of the Mg-4% Zn alloy. Microstructural examinations of the corrosion product and the corroded surface indicated that an accelerated micro- galvanic effect by the Mg2Sn-phase particles and a less protective corrosion product on the surface were responsible for the increased corrosion rate at a higher Sn content.

Mg-Zn-Sn alloy, Microstructure, Corrosion properties, Micro-galvanic effect