Even galvanic corrosion may (not say is) not be a problem, fretting
corrosion should be a concern.
http://www.amp.com/products/technology/articles/dd68_1.stm
If the force is very high (stress) and on/off is not that often, you may
(not say are) worry about cat whiskers (zinc).... If you are un-lucky,
you may have "fur coat" instead...Dave is going to tell me he filled up
nitrogen, argon in the package... I guess...;-(
jk
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Dave Hillman
>Sent: Thursday, September 11, 2003 12:36 PM
>To: [log in to unmask]
>Subject: Re: [TN] Zinc Plating Finish
>
>
>Hi TechNet! Steve - you have fallen into the galvanic series
>trap! There is the potential for a galvanic reaction between
>Zn and Sn but there are several other factors which need to be
>considered - the Galvanic Series chart is only a first order
>approximation of a possible reaction. Your cathode-to-anode
>ration, the type/use of coatings (postcoat, chem film), the
>"chemistry" of the use environment, and how "sealed" the
>electronic assembly is designed all play a role in the amount
>and type of corrosive attack on the Zn plating. There will be
>a paper at the IPC Fall meeting on the subject of galvanic
>compatibility of the new immersion finishes and aluminum which
>may be helpful.
>
>Dave Hillman
>Rockwell Collins
>[log in to unmask]
>
>
>
>
> Steve Gregory
> <[log in to unmask] To:
>[log in to unmask]
> m> cc:
> Sent by: TechNet Subject: Re:
>[TN] Zinc Plating Finish
> <[log in to unmask]>
>
>
> 09/11/2003 11:16
> AM
> Please respond to
> "TechNet E-Mail
> Forum."; Please
> respond to
> SteveZeva
>
>
>
>
>
>
>Hi Victor!
>
>What will probably happen is that the Zinc will start to
>corrode because of the galvanic action between itself and the
>tin, or tin / lead. Go to:
>
>http://www.ccfast.com/ccfcorrosion.html
>
>There you will see a Galvanic Series chart, and a simple
>explaination about Galvanic action. Zinc, and Tin or Tin /
>Lead isn't all that far apart in the chart, but far enough
>that the Zinc will corrode.
>
>-Steve Gregory-
>
>
> Fellow TechNetters:
>
> What are the exposures of having or selecting a ZINC
>plating finish for an ELECTRICAL CONTACT such as a solder less
> crimp connector and straight pin connector. What can occur if these
> finishes are mixed mated with a SnPb or Sn finish surface.
>
> Victor,
>
>
>
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