Effects of Alloying Elements on the High-Temperature Oxidation Resistance and Wettability of the Sn-9Zn Alloy

In this paper the effect of different alloying elements (Ga,Ge,Al,Ce,Ni) on the oxidation resistance and wettability of Sn-Zn based lead-free solders at high temperature (250 degC) was studied. The results of changes of solders' surface colors at high temperature and thermal gravimetric analysis (TGA) show that the adding of Ga and Al can evidently improve the oxidation resistance of Sn-9Zn based lead-free solder. But the effects of Ge, Ni, Ce aren't so perfect. The effect of various alloying elements on the wettability of Sn-9Zn solder was examined and its results indicate that the wettability of solder would be worsen by adding Al, but optimized by adding suitable Ga Ge or Ce. Also the melting point was investigated and it's concerned that the melting point is decreased with the addition of Ga. And the addition of Ge, Al, Ni, Ce didn't affect them significantly. In comparing of the properties of oxidation, wettability, melting point, it is concluded that Ga is a promising alloying element for improving the properties of Sn-Zn based lead-free solder and the Sn-9Zn-0.3Ga alloys exhibits the excellent properties