We are concerned about "tin pest" in lead-free industrial assembly's. Are there any studies known with SAC alloys?
G.V.
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Ask the Experts Comments
Tin pest is typical an issue only with high purity tin or inoculated samples. There have been test run by Nihon Superior, Keith Sweatman tested Sn100C and it is not an issue. Both SAC and SN100C have been tested in other studies and do not form tin pest.
In his 25 years of industry experience, Mr. Seelig has authored over 30 published articles on topics including lead-free assembly, no-clean technology, and process optimization. Karl holds numerous patents, including four for lead-free solder alloys, and was a key developer of no-clean technology.
The best tin pest studies recently are by Bev Christian of Research in Motion and Keith Sweatman of Nihon Superior. The industry is leaning towards the belief that tin pest is unlikely to be an issue for Pb-free solder joints except for those environments that are cold consistently for very long periods of time (think north pole, south pole, refrigeration or deep space). The reason for this is that it seems possible that periodic exposure to elevated temperatures may “reset” the tin pest clock.
Dr. Hillman's specialties include best practices in Design for Reliability, strategies for transitioning to Pb-free, supplier qualification, passive component technology and printed board failure mechanisms.
