Characterization of Sn-Bi and Sn-Bi-Zn alloys

Abstract

A B S T R A C T Lead-free solders are offering better alternative properties compared to the conventional Sn-Pb solders. The requirements of soldered joints and solder alloys are good mechanical properties, wettability etc. The present work is about the investigation of tensile and shears properties of two alloys Sn-58Bi and Sn-57Bi-1.3Zn in comparison with conventional Sn-38Pb alloy. Contact angle, spread in area and capillary rise is also investigated in the present work. It is observed that the lead free solders have better mechanical properties in comparison with conventional Sn-38Pb alloy. The alloys exhibited good wettability behavior thereby exhibiting good solderability properties. SEM studies of tensile and shear fracture show ductile mode of fracture for Sn-Pb and Sn-Bi-Zn alloys whereas cleavage facets were observed incase of Sn-Bi alloy. Sn-Bi and Sn-Bi-Zn alloys are attractive alternatives to Sn-Pb solders in the lower processing temperatures like in printed circuit boards and other applications.