The effects of Ni nanoparticles addition on shear behavior and microstructure of Sn-Ag Lead-free solder

In this article, the effects of Ni nanoparticles addition on shear property and microstructure of Sn-3.5Ag Lead-free solder joint was studied. The nickel nano-composite Sn-3.5Ag solder was prepared by adding dispersant to the dry nanoparticles and mechanically stirred Ni nanoparticles into the Sn-3.5Ag Lead-free solder paste. The shear force of the Sn-3.5Ag solder, 0.5 and 1.0 wt% nickel nano-composite solder was tested respectively at reflow 120s and 240s. The result shows that adding nickel nanoparticles can improve the shear performance of the soldered joint; the shear force of the soldered joint is highest when adding 0.5 wt% Ni nanoparticles at reflow 240s. The SEM observations shows that the hexagonal Cu₆Sn₅ IMC (intermetallic compound) in the inside solder is disappears gradually and the morphsa of the IMC that on the interface of the solder joint becomes planar after adding Ni nanoparticles into solder.