A new Bi5Sb8SnRE quaternary alloy was formed by adding 0.25wt%-0.75wt% rare earth (RE)Er into Bi5Sb8Sn solder alloy to study the effect of its mechanical property.The results show that adding micro amount of Er could refine the microstructure.Meanwhile,more uniform microstructure,improvements of the mechanical properties were obtained with Er additon.Comparing with Bi5Sb8Sn matrix, the tensile strength and shear strength increased by 41.8% and 83.0% respectively when Er adds up to 0.5wt.%; However,the Microstructure coarsened and the mechanical properties were decreased when the addition of Er more than 0.5wt.%.

In this study, AlF3was added into the Zinc flux and the spreading area of Zn20Sn of every flux formula was measured. The spreading area of Zn20Sn of different temperatures of the optimal content of the AlF3was measured as well. The result showed that the spreading area of Zn20Sn increased with the content of AlF3increasing when the content was below 2%. the spreading area of Zn20Sn decreased with content of AlF3increasing when the content of AlF3exceeded 2%. The spreading area of Zn20Sn was increased 126% than that of the matrix solder when the temperature was 470°C and the content of AlF3was 2%.