IEEE Transactions on Components and Packaging Technologies, Vol. 29, No. 2, pp. 402-410, June, 2006

Contact Resistance and Fretting Corrosion of Lead-free Alloy Coated Electrical Contacts

J. Wu and M. Pecht
University of Maryland
College Park, MD 20742


As lead-free solders replace tin-lead solders in soldering, it is also expected that lead-free solder alloys will be used as contact finish materials for electrical contacts. In this study, the contact resistance and fretting corrosion of tin-silver-copper and tin-copper coatings were investigated and compared with tin-lead eutectic coating. The contact resistance before and after different aging conditions, including mixed flowing gas, steam, and dry heat aging, was examined. Tin-silver-copper and tin-lead alloy coatings have similar performance on contact resistance versus contact normal force after dry heat aging and MFG aging. Severe degradation was found on tin-silver-copper coatings after steam aging. Higher contact force is suggested in the application of tin-silver-copper solder alloy coating than for eutectic tin-lead alloy coatings. Fretting corrosion on tin-silver-copper and tin-copper lead-free alloy coatings was studied and compared with tin-lead coating. Fretting corrosion experiments were conducted and compared at different temperatures and normal forces. In general, tin-silver-copper and tin-copper alloys show equal or better fretting corrosion resistance than tin-lead eutectic alloy at the experimental conditions in this study.

Complete article is available to CALCE Consortium Members.

© IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.


[Home Page] [Articles Page]
Copyright © 2006 by CALCE and the University of Maryland, All Rights Reserved