Effect of Ni and Co nanoparticle-doped flux on microstructure of SAC305 solder matrix

Microstructure of the eutectic region and β-Sn grain of the solder matrix play an important role in the properties of the Sn-based solder joint. In the present study, Ni and Co nanoparticle (NP)-doped flux were added into the SAC305 solder matrix to observe their effect on the microstructure of the eutectic region and β-Sn grain during the reflow process. Results reveal that after the addition of Ni and Co NP-doped flux, the size of β-Sn grain and the size of IMC particles present in the eutectic region significantly reduced. The area of the eutectic region also increased. Reduction in size of β-Sn grain and IMC particles improves the mechanical and structural properties of the solder joint.