Effects of Zn contents on microstructure, thermodynamic characteristic and mechanical properties of Sn-Bi-based lead-free solder

The effect of Zn on the microstructure, melting characteristics and mechanical properties of Sn-Bi-based lead-free solder was studied in this study. Results show that the microstructure of Sn-Bi-Zn solder changes with the addition amount of Zn. When Zn is added, Sn-Zn eutectic phase is formed in the Sn matrix, and the distribution of B-rich phase also changes. In the melting test, the peak temperature gradually changes with the increase of Zn content, decreases firstly and then increases. When the content of Zn is 1.0%, the peak temperature of the solder is 205.8 degrees C. Tensile test results show that the tensile strength changes slightly with the increase of Zn content, with a maximum value of 92.16 MPa of Sn-15Bi-1.0Zn. In the nanoindentation test, the indentation depth of the solder also changes with the content of Zn. When 1.0% Zn is added, the elastic modulus of the solder is the largest and the indentation depth is the smallest.

Automated summary

The effect of zinc on the microstructure, melting characteristics and mechanical properties of Sn-Bi-based lead-free solder was studied. The results show that zinc addition changes the microstructure of the solder, and also affects the melting temperature and mechanical properties.