Morphological and composition study on lead-free micro-alloyed solders after corrosion test

Electroanalytical tests were carried out to investigate the corrosion behavior of various Pb-free solder alloys in NaCl bulk solution under room temperature. Scanning electron microscope (SEM) method was applied to investigate the corroded surface structure and corrosion depth using cross-sectional samples. Furthermore, energy dispersive spectroscopy (EDS) method was also applied to identify the elemental composition of the corrosion products of the solders. The results showed that one of the tested Pb-free μ-alloyed solder have lower corrosion resistance compared to other μ-alloyed Pb-free solders and to the widely used SAC305 solder alloy as well. The different corrosion resistance was explained by the different content and volume of the corrosion products, which can lead back to the differences of the original alloying components.