Investigating the effect of isothermal aging on the morphology and shear strength of Sn-5Sb solder reinforced with carbon nanotubes

An analysis of the role played by the addition of carbon nanotubes (CNTs) to the solder matrix of conventional Sn-5Sb lead-free solder was performed. In a bid to determine the potential of this new solder system, the powder metallurgy approach was used to synthesise a plain Sn-5Sb solder system and CNTs reinforced composite solder formulations of Sn-5Sb-xCNT; x = 0.01wt.%, 0.05wt.% and 0.1wt.%. Isothermal aging study was conducted on the solder joints, to examine the evolution of the interfacial intermetallic compound (IMC) layer between solder and the adjoining copper (Cu) substrate. Similarly, shear strength analysis was performed on as-reflow and aged solder joints. A considerable improvement in the wetting properties, the microstructural evolution, and the interfacial intermetallic compound (IMC) layer growth was observed in the composite solder joints. Owing to the excellent mechanical properties of CNTs, the shear strength assessment revealed that the composite solder joints gave a superior shear strength property, especially the Sn-5Sb-0.01CNT solder joint sample. (C) 2015 Elsevier B.V. All rights reserved.