Influence of Bismuth (Bi) addition on Wetting Characteristics of Sn–3Ag–0.5Cu Solder Alloy on Cu Substrate
Serkan Oguz Ahmet Mustafa Erer Yunus Türen
AbstractThis work investigates the effect of Bi addition, 1 wt.%Bi, on wettability of the Sn–3Ag–0.5Cu (SAC305) ternary pb-free solder alloy. Adding Bi to SAC305 decreased the contact angles (θ) of the Sn-2Ag-0.5Cu-1Bi quaternary pb-free solder alloy decreased which were measured by using of the sessile drop method at various temperatures (250, 280 and 310 °C) on Cu substrate in Ar atmosphere [1]. Microstructures, inter-metallic phases, and melting temperatures of alloys were characterized by optic microscope and scanning electron microscope and energy dispersive X-ray spectroscopy, X-ray diffraction, and differential scanning calorimeter, and effects of the amount of In on microstructure were investigated. The results showed that when the addition of Bi was 1 wt.%, the change in melting temperature of Sn–2Ag-0.5Cu–1Bi solder was negligible, but the contact angles (θ) of the solder alloy decreased which were measured by using of the sessile drop method at various temperatures (250, 280 and 310 °C) on Cu substrate in Ar atmosphere [1]. The lowest θ was obtained as 35,59°for Sn–2Ag-0.5Cu–1Bi alloy at 310 °C. The formation of intermetallic compounds (IMC) between the Pb-free solder alloys and the Cu substrate was observed. As a result, the studies show that the wetting capability of Sn–2Ag-0.5Cu–1B alloy is better than Sn–3Ag-0.5Cu alloy.