The effect of (0.5–3.5) wt.% Ag additions on microstructure, melting,
corrosion and mechanical properties of Sn-9Zn eutectic lead-free solder
alloy has been studied and analyzed. The study included X-ray diffraction
and scanning electron microscopy (SEM) to identify the microstructure of
these alloys. The results showed that, continuous additions of Ag caused
formation of Ag-Zn and Ag-Sn compounds which led to decrease the
precipitations of Zn in Sn-matrix. These compounds led to increase the
melting point of the alloys, which confirmed by the formation of small
endothermic peaks in the higher temperature range followed the main peak of
the DTA curves. Also, the DTA measurements confirmed that the alloy of
composition Sn-9Zn-3.5Ag is the ternary eutectic alloy. Vicker's
micro-hardness number of Sn-9Zn alloy increases with small additions of 0.5
and 1 wt.% Ag. Furthermore, it decreases to lower values with further
increase of Ag content. Also, micro-creep behaviour, creep rate and corrosion
behaviour of the Sn-9Zn-Ag alloys have been measured at room temperature.