Effects of graphene nanosheets on the intermetallic compounds layer between Sn-Ag-Cu lead-free solders and Cu substrates

0.10 wt.% graphene nanosheets (GNSs) were incorporated into lead-free solder Sn-Ag-Cu (SAC) successfully. The effects of graphene nanosheets on the intermetallic compounds layer's (IMC) formation and growth in the composite solder were investigated. The IMC's structures and compositions in the interface of SAC/0.10GNSs composite solders were studied, too. In the soldering process, solders reacted with Cu substrates. And they generated scallop-like IMC in the interface between solders and Cu substrates, which contained Cu6Sn5 and Cu3Sn. The IMC's thickness of the composite solder-SAC/0.10GNSs was thinner than the SAC's. The composite solder also had a lower diffusion coefficient. GNSs in the composite solder can inhibit the growth of IMC in the interface. And mechanism of graphene nanosheets inhibition to IMC's growth was also investigated.