Tin/Lead/Silver Alloy (Sn62/Pb36/Ag2) is a ternary solder alloy consisting of approximately 62% tin, 36% lead, and 2% silver by weight. It is renowned for its excellent soldering performance, strong mechanical properties, and reliability under thermal stress, making it a preferred material for high-performance electronic and industrial applications (Grossmann et al., 1995).
Material Overview
Physically, the Sn62/Pb36/Ag2 alloy exhibits a near-eutectic composition with a relatively low melting point (around 179 °C) and a narrow solidification range, allowing for precise temperature control during reflow and wave soldering processes. The inclusion of 2% silver significantly enhances tensile strength, fatigue resistance, and creep behavior compared to conventional Sn63/Pb37 solders. This improvement arises from the formation of fine Ag₃Sn intermetallic compounds, which reinforce the microstructure and improve mechanical stability during thermal cycling (Grossmann et al., 1995).
Chemically, the alloy demonstrates good wetting characteristics and low oxidation tendency, which promote strong metallurgical bonds between components and substrates. The combination of tin and lead ensures excellent fluidity and joint reliability, while silver reduces dissolution of copper pads and intermetallic growth during soldering. The resulting microstructure maintains stability even after prolonged exposure to fluctuating temperatures, reducing the risk of joint fatigue and delamination (El-Bediwi et al., 2010).
Applications and Advantages
Electronics and microelectronics. Sn62/Pb36/Ag2 is widely used in surface mount technology (SMT) and through-hole soldering due to its reliable wetting behavior, low melting range, and mechanical robustness. It minimizes the occurrence of tombstoning defects in SMT assembly by maintaining balanced surface tension across pads during reflow (Huang & Lee, 2001). Its fatigue resistance under cyclic thermal loading makes it particularly suited for aerospace, telecommunications, and precision electronics applications.
Industrial and manufacturing uses. Beyond electronics, Sn62/Pb36/Ag2 finds applications in antifriction bearings, molded products, and decorative metalwork, where its excellent castability and mechanical integrity are advantageous (Vendrely, 2002). The alloy’s low oxidation rate and good mechanical finish make it suitable for precision-cast components and conductive assemblies requiring long-term stability.
Performance advantages. Compared to standard eutectic Sn63/Pb37 solder, Sn62/Pb36/Ag2 offers:
- Enhanced mechanical strength and creep resistance due to Ag₃Sn intermetallic reinforcement.
- Improved thermal fatigue resistance for long-term reliability.
- Reduced dissolution of copper pads during soldering.
- Excellent wetting and low void formation in reflow applications.
Goodfellow Availability
Goodfellow supplies Tin/Lead/Silver (Sn62/Pb36/Ag2) alloy in various forms suitable for research, microelectronic fabrication, and precision engineering applications. This alloy is available as wires, foils, and ingots, offering consistent performance in high-reliability soldering and joining environments.
Explore Tin/Lead/Silver (Sn62/Pb36/Ag2) and related solder alloys in Goodfellow’s online catalogue: Goodfellow product finder.
References
- Grossmann, G., Weher, L., & Heiduschke, K. (1995). Properties of Thin Layers of Sn62Pb36Ag2. International Electronics Manufacturing Technology Symposium. https://doi.org/10.1109/IEMT.1995.526211
- Huang, B., & Lee, N. C. (2001). Anti-Tombstoning Solder Alloys for Surface Mount Applications.
- El-Bediwi, A. B., Lashin, A. R., & Kamal, M. (2010). Microstructural Evolution and Physical Properties of Lead-Tin Alloys Synthesized by Melt-Spinning Technique. Materials Science: An Indian Journal.
- Vendrely, M. (2002). Lead-Tin Alloys Containing Silver and Copper, Useful for Making Molded Products, Jewelry, Fuses, and Antifriction Bearings.
- Gaver, C. C. (2005). Tin and Tin Alloys. https://doi.org/10.1002/0471238961.20091407012205.A01.PUB2
- Gnesin, G. G. (2015). Metals and Alloys of Bronze Age: From Middle to Modern Times. II. Gold, Silver, Tin, Lead, Mercury, and Their Alloys. Powder Metallurgy and Metal Ceramics. https://doi.org/10.1007/S11106-015-9667-X