Development of New Tin Based Formulations

Abstract

In this PhD research project, three different types of new generation lead-free solders have been developed using either cost and energy efficient microwave sintering assisted powder metallurgy or disintegrated melt deposition technique. Varying amounts of nano-sized Cu particles were incorporated into pure tin to develop high strength Sn-Cu solders using PM technique. Characterization results revealed that Sn-0.43 wt. % Cu formulation exhibits a superior combination of physical, electrical, thermal and mechanical properties when compared to the commercially available eutectic Sn-Cu solder. New lead-free Sn-Mg and Sn-Al solders were developed incorporating varying amount of Mg and Al into tin, respectively using disintegrated melt deposition technique. Low cost Mg and Al metals were selected as alloying elements in order to replace high cost silver. Physical, microstructural, thermal, electrical and mechanical characterizations were then carried out on the room temperature extruded samples. Results revealed that newly developed Sn-Mg solders exhibit noteworthy improvement in microhardness, strength and ductility while low cost Sn-0.6Al solder exhibits excellent ductility (87%) when compared to commercially available and widely used Sn based solders.