Novel interface regulation of Sn1.0Ag0.5Cu composite solders reinforced with modified ZrO_(2):Microstructure and mechanical properties

With the trends of miniaturization and high density of electronic packaging,there has been an urgent demand to open up lead-free solders with high strength and ductility.In this study,a ZrO_(2)-reinforced Sn1.0Ag0.5Cu composite solder was designed.First,surface modification on ZrO_(2) was conducted with ball milling-pyrolysis method.Subsequently,NiO modified ZrO_(2)(NiO/ZrO_(2))was added to the solder matrix with ultrasonic stirring.The morphology and interface of NiO/ZrO_(2) were discussed.Moreover,the microstructure,interface and mechanical properties of the composite solders were systematically studied.The results showed that NiO nanoparticles were evenly adhered to the ZrO_(2) surface,and the interface relationship between them was semi-coherent and coherent.Further,an appropriate addition of NiO/ZrO_(2) could refine the microstructure of composite solders.The refinement mechanism was systematically investigated.Besides,a micro-mechanical lock and non-micropored clean interface was formed between NiO/ZrO_(2) and the solder matrix.The Sn/NiO/ZrO_(2) interface system based on mutual solid solution was ingeniously designed.The ultimate tensile strength and elongation were increased synergistically,and the fracture mechanism transformed from a ductile−brittle mixed fracture mode to a ductile fracture mode.Therefore,a lead-free solder with high strength and ductility was obtained.