Effect of small additions of alloying elements on the properties of Sn-Zn eutectic alloy

Sn-Zn alloys have been considered for use as lead-free solders. Their poor wetting and oxidation resistance properties are the main obstacles that prevent them from becoming commercially viable solders. The effects of alloying elements, such as lanthanum, titanium, aluminum, and chromium, on oxidation resistance, wetting properties, and tensile properties of eutectic Sn-Zn solder are described herein. Results show the addition of alloying Ti, Al, and Cr can improve the oxidation resistance of Sn-9Zn solder. La, Ti, and Cr do not have much effect on the wetting properties, whereas Al worsens the wetting. Differential scanning calorimetry investigations reveal the solidus temperature of these solders to be ∼200°C. Addition of Cr improves ductility while maintaining tensile strength.