Thanks, Timothy. You're quite right - and I sort of implied that  in saying
the trouble may be with the Nickel layer. I just forgot to mention the role
of the gold specifically in protecting the Nickel layer from oxidation, and
that the nickel problem would be the result of said passivation.

More haste, less speed with my answers! (Never did work out what the really
means)

Peter



Tim Reeves <[log in to unmask]>  15/01/2003 02:35 AM
Sent by: TechNet <[log in to unmask]>

Please respond to "TechNet E-Mail Forum."; Please respond to Tim Reeves

              To:  [log in to unmask]
              cc:  (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group)
              Subject: Re: [TN] voids in gold plated holes








I would disagree. The reason the gold is there is to prevent oxidation
(passivation) of the underlying nickel. When that happens, it causes poor
solderability--it's hard to solder to passivated nickel.

Best Regards,
Timothy Reeves


-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Monday, January 13, 2003 4:06 PM
Subject: Re: voids in gold plated holes



Marie,

Welcome to TechNet!

Although no expert, my reaction is that voids in the goldplating would not,
in itself, cause poor vertical fill in the holes. The gold should burn off
during soldering and wetting should be to the underlying Nickel (presumably
this is an ENIG board). It seems to me that the problem is either with the
underlying copper plating or else the Nickel layer plated onto that. Have
you done any cross-sections of affected areas?

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