Effects of Nano-TiO2 additions on thermal analysis, microstructure and tensile properties of Sn3.5Ag0.25Cu solder

For development of a lead-free composite solder for advance electrical components, a series of Sn3.5Ag0.25Cu (SAC) solders containing TiO2 nanopowders have been studied. The results showed that the addition of 0.25–1 wt.% TiO2 nanopowders into the lead-free SAC solder caused its liquidus temperature to increase by about 3.5–5.9 °C. Metallographic observations of the lead-free SAC composite solders revealed a reduction in the grain size of β-Sn, Ag3Sn phase and Ag3Sn phase located between the spacing lamellae. In terms of mechanical behavior, the addition of larger weight fractions of TiO2 nanopowders in lead-free SAC solder matrix led to an improvement in microhardness, 0.2%YS and UTS. However, ductility of the lead-free SAC composite solders was observed to decrease.