It's a mobile phone application.
Salt mist is often used as a way of obtaining a measure of the general
corrosion resistance of an assembly. However I'm sure you could spend your
coffee break thinking up salty environments anywhere in the world that a
mobile phone could experience....
Eric Christison Msc
Mechanical Engineer
Consumer & Micro Group - Imaging Division
STMicroelectronics
33 Pinkhill
Edinburgh
EH12 7BF
UK
Tel: +44 (0) 131 336 6165
Fax: +44 (0) 131 336 6001
-----Original Message-----
From: David Douthit [mailto:[log in to unmask]]
Sent: Tuesday, May 04, 2004 5:56 PM
To: TechNet E-Mail Forum.; Eric CHRISTISON
Subject: Re: [TN] Corrosion resistance of Ni/Au plating
Eric,
Just exactly how does this "salt fog" test correspond to your possible
end use environments?
David A. Douthit
Manager
LoCan LLC
Eric CHRISTISON wrote:
>Ok, thanks for the info.
>
>No clear cut answers but I guess PCB finish doesn't make that much
>difference.
>
>Can anyone tell me if lead free solders perform better in corrosive
>environments?
>
>Thanks,
>
>Eric Christison Msc
>Mechanical Engineer
>Consumer & Micro Group - Imaging Division
>STMicroelectronics
>33 Pinkhill
>Edinburgh
>EH12 7BF
>UK
>
>Tel: +44 (0) 131 336 6165
>Fax: +44 (0) 131 336 6001
>
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
>Sent: Tuesday, May 04, 2004 3:48 PM
>To: [log in to unmask]
>Subject: Re: [TN] Corrosion resistance of Ni/Au plating
>
>
>Hi folks! Some additional data - we (e.g. the industry technoweinees)
>are much too quick to jump to the conclusion that we have a galvanic
>compatibility problem when using either immersion gold or immersion
>silver pwb finishes. Rockwell Collins published a paper at the 2003 IPC
>Fall meeting which demonstrated that the galvanic impact was secondary
>to a standard corrosion reaction in a salt fog test - i.e. our tin/lead
>test samples which were in a galvanically happy couple situation
>underwent healthy corrosion. The galvanic compatibility tables are very
>important and should not be ignored but they also can be misleading
>depending on the environment/configuration. Collins has a follow up
>immersion silver, immersion gold, immersion tin, and tin/lead galvanic
>corrosion study in progress and will report the results sometime in
>early 2005.
>
>Dave
>
>
>
> Vladimir Igoshev
> <[log in to unmask] To: [log in to unmask]
> > cc:
> Sent by: TechNet Subject: Re: [TN] Corrosion
>resistance of Ni/Au plating
> <[log in to unmask]>
>
>
> 05/04/2004 09:19
> AM
> Please respond to
> "TechNet E-Mail
> Forum."; Please
> respond to
> Vladimir Igoshev
>
>
>
>
>
>
>
>Rudy,
>
>It's not supposed to be any Au layer left after re-flow. It desolves in
>solder.
>
>Vladimir
>Sent from my Blackberry Wireless
>Vladimir Igoshev, 519-888-7465 ext.5283
>
>
>-----Original Message-----
>From: Rudy Sedlak <[log in to unmask]>
>To: [log in to unmask] <[log in to unmask]>
>Sent: Tue May 04 10:05:27 2004
>Subject: Re: [TN] Corrosion resistance of Ni/Au plating
>
>Central to this issue is the question of whether the Gold was
>completely covered by the Tin/Lead solder.
>
>I suspect it was not, and if it was not, this would set up a galvanic
>cell, which would accelerate the attack on the Tin Lead dramatically.
>
>Rudy Sedlak
>RD Chemical Company
>
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