This Lead/Tin alloy with a composition of Pb75/Sn25 remains one of the most traditional and reliable materials in electronic soldering and metallurgical joining applications. Known for its excellent wetting behavior, ductility, and stable electrical performance, this alloy has been a cornerstone in the manufacture of electronic circuits and precision assemblies for decades. Its well-balanced composition provides a robust combination of mechanical strength and thermal conductivity suitable for a wide range of joining processes.
Material Overview
The Pb75/Sn25 alloy consists of 75 wt% lead (Pb) and 25 wt% tin (Sn), forming a biphasic microstructure with both α-Pb and β-Sn solid solutions. This mixture provides moderate hardness with excellent plasticity, allowing the material to absorb mechanical and thermal stresses without cracking. The melting range lies between 183 °C and 250 °C, depending on microstructural refinement and cooling rate. Lead contributes to ductility and corrosion resistance, while tin enhances strength, wetting capability, and adhesion to copper and other metallic substrates.
Applications and Advantages
Pb75/Sn25 is extensively used as a solder alloy for electrical and electronic assembly, plumbing, and radiation shielding. Its low melting point and smooth solidification behavior make it highly suitable for manual and automated soldering operations. The alloy’s predictable wetting on metallic surfaces ensures consistent electrical contact and minimizes joint porosity. Although lead-free alternatives are increasingly adopted for environmental compliance, the Pb/Sn system remains vital in specialized aerospace, defense, and heritage electronics where mechanical reliability and fatigue resistance are critical. The alloy’s excellent creep resistance and oxidation stability make it valuable in thermal interface and sealing applications as well.
Goodfellow Availability
Goodfellow provides Lead/Tin (Pb75/Sn25) alloy in various forms suitable for research and precision manufacturing. The alloy is available with certified purity levels and can be supplied in standard or custom dimensions according to project requirements. Each batch undergoes stringent quality control to ensure consistent composition and metallurgical performance, making it ideal for both laboratory and production-scale applications.
Explore Lead/Tin Pb75/Sn25 and other advanced materials in Goodfellow’s online catalogue: Goodfellow product finder.
References
- Ren, X., Zhang, G., Xu, H., Shi, Z., & Liu, Y. (2023). Effect of Pb on microstructure and mechanical properties of tin Babbitt alloy. Journal of Physics: Conference Series, 2478(5), 052007. https://doi.org/10.1088/1742-6596/2478/5/052007
- Ubachs, R. L. J. M., Schreurs, P. J. G., & Geers, M. G. D. (2006). Microstructure dependent viscoplastic damage modelling of tin–lead solder. Journal of the Mechanics and Physics of Solids, 54(12), 2762–2792. https://doi.org/10.1016/J.JMPS.2006.05.001
- Niu, X., & Lin, K.-L. (2016). The microstructure and mechanical properties of Zn–25Sn–XAl (X = 0–0.09 wt%) high temperature lead-free solder. Materials Science and Engineering A, 676, 33–41. https://doi.org/10.1016/J.MSEA.2016.09.061
- Kamal, M., & Gouda, E. S. (2006). New lead-containing solder alloy with improved properties. Radiation Effects and Defects in Solids, 161(8), 469–475. https://doi.org/10.1080/10420150600799591