Surface treatment method for fatigue-resistant solder

U.S. Patent Number: 5340411

Abstract: The surface of a fatigue-resistant eutectic or near-eutectic lead/tin solder containing at least one doping element of cadmium, indium, and antimony is treated with an aqueous solution of an acidic chloride or acidic nitrate. The surface treatment method of the present invention removes, or substantially reduces, the presence of any cadmium, indium, and/or antimony, as well as the oxides of tin and lead, leaving a surface that is substantially tin and lead. The resulting treatment renders the solder compatible with mildly reducing fluxes of low activity and improves the wettability of the solder.

Inventors: Megerle; Clifford A. (Thousand Oaks, CA), Wong; Boon (Canoga Park, CA)

Assignee: Hughes Aircraft Company (Los Angeles, CA)

Application Number: 08/134,720

Issued: 1994-08-23

Expired: 2006-08-23

Classes: 148/26 ; 148/23

Field of search: 148/23,26

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