Pete: At risk of bringing up the obvious, I remind you that for galvanic corrosion to occur, the two areas must be electrically connected. In many cases where galvanic corrosion can occur, some surfaces, and Aluminum and Tin qualify, are protected because the oxide which forms has high resistance, thus minimizing electrical conductivity.
Rudy Sedlak
--- On Thu, 7/7/11, Pete <[log in to unmask]> wrote:
From: Pete <[log in to unmask]>
Subject: [TN] ENiG causing galvanic corrosion?
To: [log in to unmask]
Date: Thursday, July 7, 2011, 9:07 AM
We've got an assembly here showing all kinds of galvanioc corrosion after humidity tests. Looking at the galvanic chart, I notice that gold and tin are pretty far apart. Our tin plated shields are what's corroded.
Am I thinking too much into this? Would ENiG on PCB really act as the cathode for tin plating, aluminum hardware, etc.? That would mean an awful lot of corrosion out there, there's lot's of board assemblies like this.
Pete
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