Hi Pete,

If the PCB had thin, porous gold, you may have not seen it visually after the first reflow. But after the board goes through the wave the gold gets leached off and the non-wettable, oxidized nickel would be exposed.

Steve

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Pete
Sent: Friday, June 10, 2011 9:59 AM
To: [log in to unmask]
Subject: Re: [TN] Black Pad?

The second batch of pictures showed a lot more black pad/tar/whatever.  So now I'm curious - if it is oxidized Ni, from black pad or any reason, shouldn't it have appeared prior to the wave process that couldn't wet?

Pete

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