Microstructures and properties of Sn-0.3Ag-0.7Cu solder doped with graphene nanosheets

Low silver Sn-0.3Ag-0.7Cu (SAC0307) solders with different amounts of graphene nanosheets (GNSs) prepared by powder metallurgy were used to investigate the impacts of GNSs on the microstructures, melting temperature, wettability, and tensile strength of the SAC0307-xGNSs (x = 0, 0.01, 0.03, 0.05, 0.07, and 0.09 wt%) solders. The experimental results indicate that the wettability of SAC0307 solder can be improved significantly by adding GNSs and the melting temperature of the solder sample ranges from 219.6 to 222.7 degrees C. It is also revealed that with increasing GNSs content, the morphology of GNSs in the solder matrix changed from the initial dispersion distribution to the agglomeration, while the diameter and depth of the dimples of the solder joint fracture showed a tendency of increasing first and then decreasing. Doped with 0.07 wt% of GNSs, the solders showed the largest tensile strength. When GNS addition exceeds 0.07 wt%, it will induce negative effects on tensile property of the solder.