The Effects of Antimony Addition on the Microstructural, Mechanical, and Thermal Properties of Sn-3.0Ag-0.5Cu Solder Alloy

The Microstructure, Thermal, and Mechanical Properties of Sn-3.0Ag-0.5Cu-xSb High-Temperature Lead-Free Solder

“…With the increase of Sb content, the white bulk SnSb phase gradually becomes larger, IMCs become thinner, and the acicular intermetallic compound increases and pinches along the grain boundary. According to previous reports [ 7 , 23 ], the needle-like intermetallic compounds are Ag 3 Sn and Ag 3 (Sn, Sb). These were confirmed in the subsequent EDS analysis.…”

“…From these SEM images, it can be clearly seen that there are white bulk phases distributed in the matrix. Combining the element distribution diagram of Sn-3.0Ag-0.5Cu-25Sb in Figure 2 with that in [ 1 , 7 ], it can be determined that the white bulk phase is the SnSb phase and the matrix is the β-Sn phase. With the increase of Sb content, the white bulk SnSb phase gradually becomes larger, IMCs become thinner, and the acicular intermetallic compound increases and pinches along the grain boundary.…”

“…Therefore, the electronics industry needs new solder alloys to replace the solder of Sn-Pb. Among the alloy systems reported by the research team, the more promising is tin-based solder alloys [ 6 , 7 , 8 , 9 ]. In recent years, the research on Sn-Ag-Cu (SAC) solder alloys with high silver content has increased exponentially, because they usually have good mechanical behavior and good welding ability, making them a promising material for microelectronic applications [ 10 , 11 , 12 , 13 , 14 ].…”

“…According to some research studies, the addition of Sb and other elements could obtain good mechanical properties. The reasons for the improvement are the solid solution hardening effect of Sb, the hardening effect of the SnSb phase and the existence of Ag 3 Sn intermetallic compounds in the β-Sn matrix [ 7 , 20 ]. Research also showed that the addition of Sb could inhibit the formation of coarse β-Sn and refine the precipitation of Ag 3 Sn, thereby improving the mechanical and thermal behavior of Sn-Ag-Sb solder [ 8 , 20 ].…”

“…Moreover, the addition of 1.5 wt.% Sb could narrow the temperature range of solidus and liquidus, which is an ideal result for actual welding process. Phairote and Thawatchai found that after adding Sb, the microstructure of the alloy is improved, the IMC distribution is more uniform, and new Ag 3 (Sn, Sb) and Cu 6 (Sn, Sb) 5 IMC are formed around the β-Sn phase [ 7 ]. Chen and Li added Sb to the Sn-Ag-Cu solder to prepare a Sn-3.5Ag-0.7Cu-1Sb alloy.…”