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General observations
Despite the many variables that can influence Lead-Free joint reliability, it is possible to make the following generalisations;
- Tin-rich Lead-Free solders containing additional amounts of silver, copper, antimony and bismuth show broadly similar reliability to conventional tin-lead solders.
- The range of commercially available tin-silver-copper (SAC) alloys all appear to show similar reliability performance characteristics to each other.
- Tin-lead solder alloys can exhibit higher fatigue lives than Lead-Free solders when exposed to more severe conditions (i.e. higher temperatures and strain levels).
- Certain Lead-Free alloys containing up to 5% bismuth can show very good reliability, as long as no lead contamination is present.
- The bulk properties of a solder alloy may not be a good indicator of solder joint reliability.
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