Ti addition to enhance corrosion resistance of Sn–Zn solder alloy by tailoring microstructure

[Display omitted] •Trace amount of Ti was added to Sn–9Zn alloy.•Corrosion resistance of the modified alloy was significantly enhanced.•Zn-rich precipitates within the microstructure were effectively refined.•The enhanced corrosion resistance was attributed to the refined Zn-rich precipitates. The effect of trace addition of Ti on the corrosion behavior of Sn–9Zn (wt.%) solder alloy in NaCl solution was investigated using polarization and electrochemical impedance spectroscopy techniques. It is found that the corrosion resistance of Sn–9Zn alloy can be significantly enhanced by adding 0.05wt.% of Ti, evidenced by much lower corrosion current density, lower passive current density and higher impedance. Such enhancement results from the refinement of Zn-rich precipitates within the microstructure, which is conducive to forming a relatively more protective passive film on the surface of the modified alloy. This would be an important finding in the design of novel Sn–Zn solder alloys in electronic assemblies operating under aggressive conditions.