Study on the properties of Sn–9Zn–xCr lead-free solder

The influences of different Cr content to lead (Sn)–Zn solder were investigated. Sn–9Zn–xCr shows finer and more uniform microstructure than Sn–9Zn. Thermal gravimetric analysis (TGA) and Auger electron spectroscopy (AES) results show that adding Cr significantly improves the oxidation resistance of Sn–9Zn solder, and reduces the thickness of oxidation film of Sn–9Zn–xCr solder. When Cr content is 0.1%, the Sn–9Zn–0.1Cr solder have the best oxidation resistance. In addition, the effect of Cr addition on the wettability, melting point and mechanical properties of Sn–9Zn solder was discussed.