Effect of Pr on Wettability and Mechanical Property of Sn-0.3Ag-0.7Cu Lead-Free Solder

Abstract

The wettability of Sn-0.3Ag-0.7Cu-xPr solders on Cu substrate was determined by the wetting balance method， and the mechanical properties of Sn-0.3Ag-0.7Cu-xPr joints were investigated. The result showed that the wetting force of Sn-0.3Ag-0.7Cu-xPr is increased and the wetting time is decreased with the Pr content addition. Good wettability of Sn-Ag-Cu-Pr is obtained with around 0·05%-0·1% (mass fraction) Pr. When measured at 260°C， the wetting force of of SnAgCu solder was increased by 5.0% with 0.1%Pr and the wetting time of SnAgCu solder was descreased by 16.9%.The mechanical properties of soldered joints are enhanced with the addition of Pr， and the soldered joints possess the peak values of shear stress when the Pr addition is about 0.05% in Sn-Ag-Cu-Pr solder joint.