COMPARATIVE MICROSTRUCTURAL AND WETTABILITY STUDIES OF 63Sn-37Pb AND 58Sn-42In SOLDERS

Abstract

The toxicity of lead during industrial production of components and the ecological damage caused by lead containing compounds has made the use of lead in solders undesirable. Hence, the emphasis of this research is to develop a solder that has unique material properties (like the conventional lead solder) using indium as a substitute to lead. Lead-bearing solder (63Sn-37Pb) and lead-free solder (58Sn-42In) alloys were developed and subjected to the same test analysis under the same test conditions so as to analyze and compare results. Both solders are low temperature alloys. The choice of any solder by industries depends on the ability of the solder to wet the materials it joins. Consequent upon this, a copper grid plate was used to conduct different wettability tests. The wetting time for lead bearing solder and lead-free solder are 4.7 and 5.9 seconds respectively while their corresponding contact angles in degrees are57⁰ and 61⁰. The final wettability test conducted was on the wetting area. The respective wettability values (in percentage) of the total area of the copper grid covered by the molten solder are: 8.3%, and 8.6% The alloy also have the following Vicker’s Hardness Values of 18.58VHN and 16.32VHN. The microstructures of the developed alloys were studied and analyzed. The alloy’s microstructures show that they are all eutectic compositions.