Effect of graphene nanosheet addition on the microstructure, microhardness, thermal conductivity and melting behavior of a Sn-0.7Cu-based alloy fabricated via powder metallurgy technique

Various amounts of graphene nanoparticles were successfully incorporated into the Sn-0.7Cu base alloy to develop novel lead-free composite solders. Graphene, in the form of graphene nanosheets (GNS), was used as reinforcement. The synthesis was carried out using a powder metallurgy technique involving mixing, compaction, and sintering. The obtained sintered samples were characterized for their physical, mechanical and thermal properties. Optical and scanning electron microscopy with energy-dispersive spectroscopy revealed a homogeneous distribution of GNS along grain boundaries, resulting in a fine-grained ?-Sn structure. Increasing the GNS content in the Sn-0.7Cu base alloy resulted in improved microhardness and a slight reduction in density. Differential thermal analysis (DTA) showed that the melting temperatures of the reinforced samples were slightly higher than those of the base alloy. Thermal diffusivity was measured at room temperature using the flash method, revealing a significant decrease with increasing GNS content compared to the base alloy.