Investigation of microstructure and physical properties in nanocomposite solder reinforced with various percent of graphene nanosheets (SAC0307+GNSs)

Development of electronic industries, compression of electronic equipment, and removing lead from electronic circuits for environmental issues, resulted in a significant challenge in design and development of tin-based lead-free solders with physical and mechanical properties similar to old tin-lead alloys. In this regard, the set of Sn-Ag-Cu alloys with eutectic and near eutectic compositions have been proposed to replace Sn-Pb solders. As a lead-free solder alloy, low melting point, high reliability, and compatibility with various fluxes are among the properties of this category of alloys. In order to improve the properties of the joint, these solders are sometimes reinforced with different nanoparticles. In this study, Sn0.3Ag0.7Cu compound reinforced with graphene nanosheets with different weight percentages (0, 0.05, 0.1, and 0.2) was studied. Microstructure of the alloys was investigated by scanning electron microscopy(SEM) and optical microscopy. Melting temperature, wetting behavior and electrical resistivity of the solders were evaluated. According to the results, by adding graphene nanosheets, the wetting angle of the solder first decreased and then increased. This parameter showed the optimal amount for sample containing %0.1 graphene nanosheets with a %10 reduction. The melting point and electrical resistance of the solder alloy did not change significantly with compositing. With the addition of graphene nanosheets, the thickness of the intermetallic compounds Cu6Sn5 present at the interface between copper and solder was reduced up to %30.