Effects of addition of rare earth element Nd on properties of Sn-9Zn lead-free solder

Effects of the addition of rare earth element Nd on the wettability,microstructure and mechanical properties of Sn-9Zn lead-free solder were studied.The results indicate that adding trace amount of rare earth element Nd can remarkably change the wettability of Sn-9Zn lead-free solder.Especially when the content of Nd was 0.06 wt%,the wettability of solder was significantly improved due to the low surface tension.It is also found that rare earth Nd could refine the microstructure the solder.NdSn3 phase appeared in the solder with excessive addition of Nd.At the same time,shear force of Sn-9Zn-0.06Nd solder was enhanced by 19.6% as well as pull force enhanced by 26.6% compared to that of Sn-9Zn solder.