Effect of TiO2 Nanoparticles Addition on the Electrochemical Migration of Low-Silver Lead-Free SAC Alloys

The effect of the doping of TiO
2
nanoparticles on the electrochemical migration (ECM) characteristics of low-Ag lead-free SAC0807 solder alloy was examined by the means of water drop (WD) tests in 0.1 M NaCl solution at 10 VDC bias voltage. The statistical and reliability analysis of WD results revealed that for both alloys, the lifetime results follow a clearly defined log-normal distribution. SAC0807+0.1%TiO
2
showed a higher median time to failure (T
50
) than SAC0807 suggesting an advantageous effect of incorporating TiO
2
nanoparticles onto SAC0807 from the ECM point of view. However, based on statistical and reliability analysis of WD results, this advantageous effect is not enough to consider doping with TiO
2
nanoparticles promising. Scanning electron microscopy (SEM) showed a change in the morphology of the dendrites between SAC0807 and SAC0807+0.1%TiO
2
where the former showed straight and perpendicularly branched morphology while the latter showed a mixture of the trunk and lace-type morphology. Energy dispersive spectroscopy (EDS) confirmed that Sn was the principal detected element in the dendrites in both cases.