Study of melting point: Solderability and interface microstructure of SnAgCu-XSm/Cu

Rare earth element samarium was added into Sn-3.0Ag-0.5Cu solder, and the amount is 0, 0.025, 0.05, 0.1, 0.2wt% respectively. The solder SnAgCu-XSm melting point was studied by differential scanning calorimeter, the wetting spreading area on Cu substrate was measured and the interface was studied with scanning electron microscope. The results show that the melting point 217.19 °C is the lowest with Sm 0.1wt%, the wetting spreading area 50.3245mm2 is the largest with Sm 0.05wt%. The morphology of intermetallic compounds becomes smooth and its transition between the solder and Cu substrate becomes moderate with Sm content 0.05%. The thickness of intermetallic compounds reduces with the content of samarium 0.025~0.1wt%.