Hi Rudy! Sorry but I disagree with your statement on tin plating being prone to
corrosion when in contact with solder. Tin is only two steps away from tin/lead
on most galvanic series charts for fresh and/or seawater thus very little
galvanic corrosion potential exists (check out page 32, Fontana and Green, ISBN
0-07-021461-1). Tin also has relatively good corrosion resistance to atmospheric
corrosion, weak mineral acids, and many organic acids. The amount of tin plated
electronic housings that are in contact in with tin/lead on electronic products
is quite large and the number of corrosion cases reported is quite small. Tin
has lots of problems in other areas (tin whiskers, tin pest,) but corrosion I
don't see as being an area of concern. And yes ":galvanically" is a word (well,
my spellchecker thinks it is anyway!).

Dave Hillman
Rockwell Collins
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Rudy Sedlak <[log in to unmask]> on 11/04/99 06:14:08 PM

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Subject:  Re: [TN] The Case of Corrosion after Wave Flow Soldering Affair



Hans:

If you have pure Tin plated pins, electrically in contact with solder, this
is VERY prone to corrosion, as you will be getting galvanically (does that
word exist?) corrosion.  Tin is much more electropositive than solder, and
therefore will corrode readily when in contact with solder.

Does this help?

Rudy Sedlak
RD Chemical Company

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