Synthesis and characterization of bulk nano crystalline Pb free solders

Abstract

In this paper investigations were carried out to develop the bulk nano crystalline Pb free solder alloys with enhanced strength and reduced melting temperatures. For this study two lead-free solder alloys of Sn-0.7Cu and Sn-3.5Ag were chosen. High energy ball milling route was adopted for production of bulk nano crystalline solders from these alloy powders. The milling was carried out for a period of 100 hrs. The milled powders were characterized for its crystallite size and morphology changes. The result shows that for a milling time of 100 hrs the crystallite size was reduced from 132 nm to 36 nm and 117 nm to 43 nm for Sn-0.7Cu alloy and Sn-3.5Ag alloy respectively.