Investigations on the Corrosion Properties of Sn–0.5Cu–Bi–xAg Lead Free Solder Alloys in 3.5% NaCl Solution

Abstract

Various environment legislations lead to the ban of Pb in solder alloy making. Solder alloy is an integral part of electronic packaging industry. As a result of this researchers were searching for new combinations without lead which can replace Sn–Pb solder alloy. The new lead free solder joint should possess good mechanical properties, good wetting properties and good corrosion resistance properties. Many lead free solder alloys were discovered. Sn–0.5Cu–3Bi is a good candidate for replacing the Sn–Pb alloy with good properties. The addition of Ag into the alloy enhanced the properties, especially 1% by wt. Ag. In this paper, investigations on the corrosion behavior of Sn–0.5Cu–3Bi–xAg (x = 0, 0.5, 1% by wt.) in 3.5% NaCl is carried out using weight loss method. Microstructure and EDAX analysis were also conducted in the analysis. It is found that the corrosion rate is minimum with 1% by wt. addition of Ag. Corrosion rate is less when compared with the SAC (Sn–Ag–Cu). Sn–0.5Cu–3Bi–1Ag can be considered as a potential lead free solder joint with good corrosion resistance.