Effect of Multiple Reflow Cycles on the Shear Strength of Nano-Al2O3 Particles Reinforced Sn3.6Ag Lead-Free Solder Alloy

The effect of nano-Al2O3 particles reinforcement on shear strength of Sn3.6Ag solder joint exposed to multiple reflows was studied. The nano-composites of Sn3.6Ag solder were developed by mechanical dispersion of nanoparticles in the solder alloy. The melting, mechanical and microstructural properties of Sn3.6Ag composite solders with varying weight fractions of nano-Al2O3 particles were evaluated by subjecting them to multiple reflow cycles. The results showed an improvement in the wettability of the solder with inclusion of nano-Al2O3 particles. The composite Sn3.6Ag solders with 0.01–0.05 wt% nanoparticles reinforcement showed an improvement in the shear strength and ductility of the solder joint compared to monolithic solder alloy under multiple reflow cycles. Samples doped with 0.05 wt% nanoparticles and reflowed for two reflow cycles displayed an appreciable suppression in interfacial intermetallic compound’s growth and improvement in the solder joint shear strength. The addition above 0.1 wt% in solder showed a decrease in the beneficial effects of nano-Al2O3 particles reinforcement.