Metals (Jul 2022)

Effect of Ni-Coated Carbon Nanotubes Additions on the Eutectic Sn-0.7Cu Lead-Free Composite Solder

  • Xin Liu,
  • Guoge Lu,
  • Zhe Ji,
  • Fuxiang Wei,
  • Chuandang Yao,
  • Jiajian Wang

DOI
https://doi.org/10.3390/met12071196
Journal volume & issue
Vol. 12, no. 7
p. 1196

Abstract

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Sn-0.7Cu-based (all in wt.% unless specified otherwise) composite solders functionalized with Ni-coated carbon nanotubes (CNTs) with various weight proportions ranging from 0.01 to 0.2 wt.% were successfully produced. The Ni-coated CNTs were synthesized with discontinuous nickel coating by an improved electroless nickel plating technique. The microstructural, melting and wetting properties of Sn-0.7Cu-based composite solders were evaluated as a function of different amounts of Ni-coated CNTs addition. Compared to Sn-0.7Cu, it was observed that the microstructure of the composite solder added to the Ni-coated CNTs was still composed of the intermetallic compound Cu6Sn5 in a β-Sn matrix, but the micromorphology changed greatly. When 0.05 wt.% Ni-coated CNTs were added, the rod-shaped Cu6Sn5 particles disappeared, and all appeared in a form of dot-shaped Cu6Sn5 particles. DSC results showed only a slight decrease in the melting behavior of the composite solder. Experimental results unveiled that the addition of Ni-coated CNTs to Sn-0.7Cu solder could improve the wettability. With the addition of 0.05 wt.% Ni-coated CNTs, the wetting angle decreased by 13.35%, and an optimum wetting angle of 25.44° was achieved.

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