Research Status of Evolution of Microstructure and Properties of Sn-Based Lead-Free Composite Solder Alloys

Figure 21

The SEM images of interface microstructure of solder joints: (a, b) Sn-58Bi/Cu and Sn-58Bi-0.5Al₂O₃/Cu solder joints annealed for 48 h at 85°C and (c, d) Sn-58Bi/Cu and Sn-58Bi-0.5 Al₂O₃/Cu solder joints annealed for 288 h at 85°C [102].

(a)

(b)

(c)

(d)