Novel Sn-0.7Cu composite solder reinforced with ultrafine nanoscale nickel particles/porous carbon

In this study, the nickel-based metal organic framework (Ni-MOF) was carbonized at high temperature and the nanoscale nickel particles anchored in the carbon skeleton (Ni@C) with flake structure were obtained. The composite solders were subsequently prepared successfully by adding the Ni@C flakes to Sn-0.7Cu solder. The effects of Ni@C on the properties, microstructure and interface reaction of the Sn-0.7Cu solders were system-atically investigated. The results showed that the Ni@C flakes had a negligible effect on the melting point of the solders and improved the wettability significantly. The wetting angle decreased by 15.04% when the Ni@C was 0.08 wt% in content. In addition, the size of matrix 13-Sn grains were significantly reduced and the matrix 13-Sn grains appeared very fine structure after adding the Ni@C flakes. Meanwhile, the elongated (Cu, Ni)6Sn5 phase transformed from rod-shape to dot-shape. During the reflow process, the morphologies of intermetallic com-pounds (IMCs) gradually changed from shell-shaped to continuously planar, and their thickness decreased by 26.6%. The (Cu, Ni)6Sn5 forming at the interface and the porous carbons distributing in solder matrix effectively hindered the diffusion of Cu and Sn respectively and retarded the growth rate of IMCs.

Automated summary

In this study, nanoscale nickel particles anchored in a carbon skeleton (Ni@C) with flake structure were successfully prepared by carbonizing a nickel-based metal organic framework at high temperature. The addition of Ni@C flakes to Sn-0.7Cu solder significantly improved wettability, reduced the size of matrix 13-Sn grains, and transformed the elongated (Cu, Ni)6Sn5 phase. The formation of (Cu, Ni)6Sn5 at the interface and the presence of porous carbons in the solder matrix effectively hindered the diffusion of Cu and Sn, leading to a decrease in the growth rate of intermetallic compounds (IMCs).