▎ 摘　　要

The Ni nanoparticle-decorated reduced graphene oxide (Ni-rGO) reinforced Sn2.5Ag0.5Cu lead-free composite solder, as well as the interfacial intermetallic (IMC) and the shear strength of soldering joints, are investigated with scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM). The results show that Ni-rGO can be synthesized by the thermal decomposition method, and the adsorption type between Ni atoms and rGO is chemisorption. When the amount of Ni-rGO addition reaches 0.05wt%, the high strength and toughening Ni-rGO reinforced lead-free composite solder is obtained, with a tensile strength and elongation of 58.0MPa and 32.3%, respectively. The growth of the interfacial IMC layers is restrained by the addition of Ni-rGO, and the highly reliable soldering joints are obtained accordingly. When the amount of Ni-rGO addition reaches 0.05wt%, the shear strength of the Ni-rGO reinforced lead-free composite solder is 28.1MPa, which is 26.6% higher than that of the plain Sn2.5Ag0.5Cu soldering joints. With the increase in the amount of Ni-rGO, the fracture pattern is transforme from a ductile-brittle mixed fracture to a ductile fracture. Additionally, the fracture pathway shifts from a transition zone, consisting of soldering seam and interfacial IMC, to the direction of the soldering seam.