LEAD FREE ALLOY FOR SOLDERING

摘要

PURPOSE: A Sn-Ag-Cu-In quaternary lead free alloy for soldering is provided which improves strength of a soldering bonding part by adding indium (In) to a Sn-Ag-Cu ternary lead free alloy composition, thereby reducing melting temperature of soldering process, improving wettability of solder and fluidity of metal, inhibiting formation of oxides and increasing heat resistance fatigue strength. CONSTITUTION: The lead free alloy for soldering is characterized in that it is a Sn-Ag-Cu-In quaternary lead free alloy for soldering formed by adding indium (In) to a Sn-Ag-Cu ternary lead free alloy as constituents, wherein the Sn-Ag-Cu-In quaternary lead free alloy for soldering comprises 2.0 to 4.0 wt.% of silver (Ag), 0.5 to 1.5 wt.% of copper (Cu), 0.1 to 2.0 wt.% of indium (In) and a balance of tin (Sn).