Brian is right, unplated Nickel is difficult, if it weren't we would have EN
boards not ENIG, but surely prewetting the nickel by dip tinning will not
remove the nickel. You will have a solder coated nickel plated wire..
If the wire is not too fine, you could try prepping the end to be soldered
using some specially tipped tweezers. The sort with rubber blocks, the
rubber is loaded with abrasive particles, this would reduce the oxide
removal burden, and hopefully to a level where an ordinary FCSW would cope.
Or maybe there is some spec against this procedure as well?
Regards
Mike Fenner
Applications Engineer, European Operations
Indium Corporation
T: + 44 1908 580 400
M: + 44 7810 526 317
F: + 44 1908 580 411
E: [log in to unmask]
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Pb-free: www.Pb-Free.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Brian Ellis
Sent: Friday, May 30, 2003 7:59 AM
To: [log in to unmask]
Subject: Re: [TN] Nickel plated wire...
Steve
I agree with David and, in fact, would NOT recommend Ni-plating for
soldering to. It can be reliably soldered using strong halide-activated
fluxes, preferably water-soluble. You may not wish to use these for
rework for obvious reasons. As David says, pretinning is a good solution
provided you wash off the flux residues from the pretinned wire. But
then, pre-tinned wire is no longer nickel plated, is it? It is tinned.
So why not use tinned wire in the first place? This is obvious and I
cannot understand a MIL spec that disallows tinned wire and allows
silvered wire, which could whisker like hell if you so much as curve it
into place. Doesn't make sense. But then neither do thousands of specs,
standards and other regulations written by technocrats whose only aim in
life is to ensure they appear busy enough to keep their cushy job. I
have always claimed that good commonsense, based on science, is worth
more than ten-thousand standards. This is just a case in point.
Brian
Steve Gregory wrote:
> Hi All,
>
> I was posed this question by one of our customers. I don't have any
> experience with nickel plated wire, but it would seem to me to be
> difficult to solder to. I've used tin plated, and silver plated wire
> before with no problems. But I didn't know that silver plated wire had
> corrosion problems. Any inputs?
>
> In the future we are going to be changing to specify a nickel plated
> wire (M22759/10-28-9) for PWA repair. The previous part number was a
> silver plated wire. We haven't used this before. Do you or any of your
> manufacturing people know of issues with solderabiliby when using a
> nickel plated wire or any special process that should be used?
>
> The history of this is IPC-7721 paragraph 6.1 says silver plated wire
> must not be used because it can cause corrosion of wire in certain
> situations. Turns out that when you follow MIL-23200 the allowed wire is
> either silver plated or nickel plated. We would have preferred tin
> plated wire but it doesn't appear to fall under the allowed MIL-23200
> options.
>
> Thanks in advance!!!
>
> -Steve Gregory-
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