Bi、Ag对Sn-Zn无铅钎料性能与组织的影响

The influences of the addition of Bi, Ag to Sn-9Zn lead-free solder on the microstructure, wettability and mechanical properties were studied. The results show that Sn-9Zn lead-free solder has poor wettability. With the addition of Bi to Sn-9Zn lead-free solder, the improvement of wettability and shearing strength of joint can be achieved, but plasticity of joint decreases. With the addition of suitable amount Ag to Sn-9Zn lead-free solder, the improvement of wettability and plasticity of joint can be achieved obviously. With the addition of up to 1.5% Ag (mass fraction) to Sn-9Zn lead-free solder, the wettability and shearing strength of joint decreases. The microstructures of Sn-9Zn-Bi solder system are composed of β-Sn matrix, Zn-rich phase and the precipitation of Bi phase in the β-Sn matrix. The microstructures of Sn-9Zn-Ag solder system are composed of β-Sn matrix, Zn-rich phase and AgZn3 intermetallic compound.