, Volume 53, Issue 6, pp 39–41 | Cite as

Tin pest in Sn-0.5 wt.% Cu lead-free solder

  • Yoshiharu Kariya
  • Naomi Williams
  • Colin Gagg
  • William Plumbridge
Research Summary Lead-Free Solder


Tin pest (the product of the allotropic transformation of β-tin into α-tin at temperatures below 286 K) has been observed in a Sn-0.5 wt.% Cu solder alloy. Some 40 percent of the specimen surface was transformed into gray tin after aging at 255K for 1.5 years, and after 1.8 years, the proportion increased to about 70 percent. The degree of transformation in work-hardened areas is much higher than in other areas, suggesting residual stress might provide an additional driving force for the transformation into α-tin. The allotropic change results in a 26 percent increase in volume, and cracks are initiated to accommodate the changes in volume. Results indicate that tin pest could lead to total disintegration of micro-electronic solder joints. The tin-copper eutectic system may become a prominent lead-free solder, and tin pest could have major ramifications on service lifetime of electronic assemblies.


Residual Stress Solder Joint Solder Alloy Allotropic Transformation Service Lifetime 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    D. Napp, SAMPE Journal, 32 (1996), p. 59.Google Scholar
  2. 2.
    B. Trumble, IEEE Spectrum, 35 (1998), p. 55.CrossRefGoogle Scholar
  3. 3.
    For example, Lead Free Solder Project, Final Report, NCMS Report 0401RE96 (Ann Arbor, MI: National Center for Manufacturing Sciences, August 1997).Google Scholar
  4. 4.
    The Properties of Ti, Publ. 218 (Uxbtridge, U.K.: Tin Research Institute, 1954).Google Scholar
  5. 5.
    Y. Kariya, C.R. Gagg, and W.J. Plumbridge, Soldering and Surface Mount Technology, in print.Google Scholar
  6. 6.
    W.G. Burgers and L.J. Groen, Faraday Soc. Discussions, 23 (1957), p. 183.CrossRefGoogle Scholar
  7. 7.
    H.E. Hedges, Tin and its Alloys (London: Edward Arnold Ltd., 1960), p. 51.Google Scholar
  8. 8.
    G.V. Ratnor and R.W. Smith, Proc. Roy. Soc., 224 (1958), p. 101.Google Scholar

Copyright information

© TMS 2001

Authors and Affiliations

  • Yoshiharu Kariya
    • 1
  • Naomi Williams
    • 1
  • Colin Gagg
    • 1
  • William Plumbridge
    • 1
  1. 1.Materials Engineering DepartmentThe Open UniversityU.K.

Personalised recommendations