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JOM

, 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

Abstract

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.

Keywords

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.

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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.

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