Effect of rapid solidification on microstructure, creep resistance and thermal properties of Sn-10 wt.% Sb- 3 wt.% X ( X= In, Ag, Bi and Zn) lead-free solder alloys

Abstract

The harmful effects of lead on the environment and human health, coupled with the threat of legislation, have prompted a serious search for lead-free solders for electronic packaging applications. The melt-spinning processes of ternary Sn-10 wt.%Sb-3 wt.%X (X=In, Ag, Bi and Zn) were analyzed using x-ray diffractometer (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Vickers hardness tester (HV). The investigation showed that, the addition of a small amount of the third element enhances the ductility of the Sn–10 wt.% Sb lead-free solder due to the formation of a fine, homogeneous ternary microstructure.. It is concluded that, the addition of 3.0 wt% Ag improves the grain size of the ternary microstructure. Moreover, SnSb intermetallic compound, precipitated finely from the solid tin solution near the grain boundaries with antimony. This fine precipitated intermetallic compound suppresses the coarsening of the ternary structure and thus enhances solder ductility. Structural and microstructural analysis revealed that the origin of change in mechanical behaviors was due to refined beta-Sn grains and formation of intermetallic compounds (IMCs) SnSb, InSn19, β-In3Sn and Ag3Sn. The results indicated that the melting point of Sn-10Sb-3 wt.% Ag and Sn-10 wt.%Sb- 3 wt.% Zn alloys reduced to 230 and 240 ˚C respectively. In particular, the zinc addition at 3 wt.% is the most effective in improving solder ductility. The good creep resistance of Sn-10 wt.% Sb-3 wt.% Zn lead-free solder correlated to a large β-Sn grain size and complete soluble of SnSb IMC particles in the β-Sn matrix.

Development of holmium doped eutectic Sn-Ag lead-free solder for electronic packaging

“…Solders containing lead can cause harm to human health and this had led to the use of Pb-free joints as alternatives for conventional Pb-Sn solder alloys (Ku et al , 2003; Braga et al , 2007). The most common lead-free solders are tin-silver-copper, tin-bismuth and tin-zinc alloys (EL-Daly et al , 2009; Kamal and Goda, 2006; Shalaby, 2015a; Shalaby, 2015b). Shalaby and co-workers have studied and analysed the characteristics and mechanical properties of tin-silver and bismuth-silver Pb-free solder alloys (Shalaby et al , 2018a; Shalaby and Elzanaty, 2020; Jubair et al , 2019; Shalaby et al , 2018b; Gumaan et al , 2018).…”

Effect of Terbium Additions on Microstructural, Thermal and Mechanical Properties of Eutectic Sn-3.5Ag Pb- Free Solder for Low Cost Electronic Assembly

“…Lead free solder alloy have been used widely as a part of electronic circuit for its excellent properties (Ref 2,3).The type of lead free Sn-Ag solder is considered as a good alternative to Sn-Pb solder (Ref 4). It gives a fine wettability, high strength in addition to better resistance to thermal fatigue and creep ( Ref 5,6,7). The development of new lead free solders at least with the same mechanical properties in addition to microstructures stability as eutectic Pb-Sn solder is an urgent errand.…”