Fabrication and properties of NiO-modified Al2O3 reinforced Sn1.0Ag0.5Cu composite solder and soldering performance

NiO-modified Al2O3(NiO–Al2O3) as the reinforcing phase of solder matrix was prepared by impregnation method, and then, the prepared reinforcing phase was mixed with Sn1.0Ag0.5Cu at a mass ratio of 10:1 to conduct soldering experiments. In this study, we discussed the morphology, phase composition and interfacial coherence of nickel oxide nanoparticles during the preparation of reinforcement and then studied the properties of the composite solder with different content NiO–Al2O3. The shear strength of solder joints and the morphology of the intermetallic compound (IMC) layer were also investigated. The results showed that NiO nanoparticles prepared by impregnation method were deposited on the surface of Al2O3, and the interface of NiO–Al2O3 was a semi-coherent interface, which was a good metallurgical bond. When the doping content was 0.7 wt%, the wetting angle was the smallest and the shear strength of solder joint was highest. With the addition of NiO–Al2O3 increased, the scallop-like interface IMC was more continuous and regular under the optimal doping amount (0.7 wt%). Microstructural studies have also shown that NiO–Al2O3 nanoparticles were adsorbed on the surface of the IMC layer, effectively preventing the diffusion of metal atoms. The effect of NiO–Al2O3 addition on shear fracture was described. When the NiO–Al2O3 content was 1 wt%, the reinforcement exhibited obvious agglomeration, which led to an increase in the thickness of the IMC layer and an irregular hill-like interface morphology.