Journal of Failure Analysis and Prevention

, Volume 10, Issue 6, pp 437–443 | Cite as

Tin Pest: Elusive Threat in Lead-Free Soldering?

Feature

Abstract

Tin pest is the result of an allotropic transformation of tin from its β phase to its α phase at temperatures below 13 °C. This transformation is accompanied by a change in density from 7.31 to 5.77 g/cm3. The resulting expansion usually results in degradation of the affected part, as the α phase material is mechanically weak and over time becomes little more than a gray powder. The tin pest effect is cumulative unless the sample in question is exposed to temperatures above 70 °C or so, where some reversion back to white tin has been observed. However, by this point a tin sample’s physical integrity may have been destroyed by the partial β to α transformation. The transformation to α tin is inhibited strongly by soluble alloying elements such as bismuth and antimony at concentrations of about 0.5%, or lead at concentrations of about 5%. Hence, tin pest is generally observed only in quite pure tin. However, nearly pure tin alloys may become common. For example, the advent of the European Union’s RoHS law, which essentially eliminates lead from solder, has spawned lead-free alloys that can be almost pure tin and may be at risk of tin pest. This risk has caused some concern over the long-term stability of emergent, lead-free solders during low temperature service. This overview article is written in light of this concern.

Keywords

Tin pest Allotropic transformation Tin pest incidence and kinetics Cold temperature service Environmental effects on tin 

Notes

Acknowledgments

I am appreciative of all of the recent work of Professor Bill Plumbridge. He is been a leader in tin pest research in this era. I am also grateful for the help of the Tin Institute (ITRI), most notably from Dr. Paul Harris.

References

  1. 1.
    Harris, P.: Tin pest: a review of the current state of knowledge. Unpublished, private communication, ITRI (2000)Google Scholar
  2. 2.
    Le Couteur, P., Burreson, J.: Napoleon’s Buttons: How 17 Molecules Changed History. Tarcher, New York (2004)Google Scholar
  3. 3.
    Chiavari, C., et al.: Deterioration of tin-rich organ pipes. J. Mater. Sci. 41, 1819–1826 (2006)CrossRefADSGoogle Scholar
  4. 4.
    Taylor, A.: An Introduction to X-Ray Metallography. Chapman and Hall, London (1945)Google Scholar
  5. 5.
    Homer, C.E., Watkins, H.C.: Transformation of tin at low temperatures. Met. Ind. 60(22), 364–366 (1942)Google Scholar
  6. 6.
    Havia, E.: Private communication, December (2009)Google Scholar
  7. 7.
    Burns, N.D.: A tin pest failure. J. Fail. Anal. Prev. 9, 461–465 (2009)CrossRefGoogle Scholar
  8. 8.
    MacIntosh, R.M.: Tin in cold service. In: Tin and its Uses, vol. 6, pp. 72. Tin Research Institute Inc., USA (1966)Google Scholar
  9. 9.
    Rogers, R.R., Fydell, J.F.: Factors affecting the transformation to grey tin at low temperatures. J. Electrochem. Soc. 100(9), 383–387 (1953)CrossRefGoogle Scholar
  10. 10.
    Vnuk, F.: The kinetics of β to α transformation of tin. In: Metal Congress, pp. 176–185 (1975)Google Scholar
  11. 11.
    Raynor, G.V., Smith, R.W.: Proc. R. Soc. 244A, 101–109 (1958)ADSGoogle Scholar
  12. 12.
    Matvienko, A.A., Sidelnikov, A.A.: The influence of relaxation of stresses occurring during the [beta] → [alpha] transformation of tin on the kinetics of the transformation. J. Alloys Compd. 252, 172–178 (1997)CrossRefGoogle Scholar
  13. 13.
    Plumbridge, W.J.: Tin pest issues in lead-free electronic solders. J. Mater. Sci. Mater. Electron. 18, 307–318 (2007)CrossRefGoogle Scholar
  14. 14.
    Joo, Y.J., Takemoto, T.: Mater. Lett. 56(5), 793–796 (2002)CrossRefGoogle Scholar
  15. 15.
    Plumbridge, W.J.: J. Electr. Mater. 37(2), 218–223 (2007)CrossRefADSGoogle Scholar
  16. 16.
    Liu, W., Lee, N.-C.: Novel SACX Solders with Superior Drop Test Performance, SMTAI, Chicago, IL, September (2006)Google Scholar

Copyright information

© ASM International 2010

Authors and Affiliations

  1. 1.Indium CorporationClintonUSA
  2. 2.Dartmouth CollegeHanoverUSA

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