Electrochemical corrosion behaviour and corrosion mechanism of Sn-9Zn-xGe solder alloys in NaCl solution

The electrochemical corrosion behaviour and corrosion mechanism of Sn-9Zn-xGe alloy in 3.5 wt.% NaCl solution was investigated using electrochemical techniques combined with surface characterization techniques. The results showed that the alloy corrosion was mainly affected by the rupture of passivation film and Cl- migration along grain boundaries. Trace Germanium (Ge) addition refined the microstructure and improved the corrosion potential of the alloy. Solder alloys containing 0.6 wt.% Ge formed a uniform and dense passivation film on the corrosion surfaces, which reduced the corrosion rate and increased the corrosion resistance.