Mechanical properties of Sn-58 wt%Bi solder containing Ag-decorated MWCNT with thermal aging tests

Abstract The mechanical properties and microstructure of Sn-58 wt%Bi solder including various levels of Ag-decorated MWCNTs (0, 0.05, 0.1, and 0.2 wt%) were investigated for use in solder joints. The electronic industry relies on Pb-free solders because lead can have harmful effects on the environment and human health. The Sn-58 wt%Bi solder is a representative low temperature Pb-free solder with high tensile strength and good creep resistance. However, the Sn-58 wt%Bi solder has poor ductility for relieving shock impact. To address this drawback, Ag-decorated MWCNTs were used to reinforce the mechanical properties of Sn-58 wt%Bi solder. The Sn-58 wt%Bi-nanocomposite solder paste was fabricated by mechanically mixing Ag-decorated MWCNTs with solder paste. The Sn-58 wt%Bi solder pastes including Ag-decorated MWCNTs were printed on a printed circuit board (PCB), and the joints were aged in an isothermal environment. Inclusion of 0.1 wt% Ag-decorated MWCNTs increased the shear strength of the solder by about 15%. The thickness of the IMC of Sn-58 wt%Bi solder increased with age.