Gold Leaded SMT devices

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We are using gold plated leads on SMT devices. Gold embrittl... - Sep 09, 2003 by

The maximum ratio of gold weight to solder alloy weight can ... - Sep 09, 2003 by davef

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#25683

Gold Leaded SMT devices | 9 September, 2003

We are using gold plated leads on SMT devices. Gold embrittlement is supposed to be a problem at concentrations above 4%. Has anyone done any work to qualify this?

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davef

#25684

Gold Leaded SMT devices | 9 September, 2003

The maximum ratio of gold weight to solder alloy weight can be calculated, to help prevent a problem from excessive gold-tin intermetallic compound (i.e., AuSn4). For the equation and its derivation, please refer to "The Use of Capillary Action Measurements for Solderability Improvement," Soldering and Surface Mount Technology, No. 9, Oct., 1991, Wela Publications, Ayr, Scotland, Table 5.

RJ Klein-Wassink gives additional references in "Soldering in Electronics" [Electrochemical Publications; ISBN: 090115024X; 1989], 4.2.5.1.

IPC-HDBK-001, page 64 gives additional references.

Here's another refrerence: "Understanding Gold Embrittlement in Surface-Mount Soldering," ISHM 1st Joint Technology Conference, San Diego, March, 1990. [ISHM changed its name to IMAPS]

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