What you say confirms our experience, that bright nickel is prone to
dewetting. We COULD solder on bright nickel, but not without many precautions, like
storing the parts in nitrogen, use ZnCl solutions, abrasive tools etc. Once wetted,
the joints seem to be acceptable, but personally, I doubt much about a soldering
process, in which the wetting front looks like a hippo's belly, slowly snailing forward and
apathetically binding onto the metal. My wetting scenario is more like what happens when
some drops of Balveni happen to fall on the landlady's best walnut table, an immediate spread
in all directions.
Rats in the bath, quite normal. When we visited a well reputed house, one of our guys observed a little pyramid on the bottom of one the numerous tanks. The owner was stunned, just peered down in the bath and had no answer. Our guy looked thoughtfully up in the ceiling....and saw a hole in the construction, just over the tank..and the pyramid. Hmmmmm...he took a long piece of a pipe that was on the floor and nocked the ceiling with a slight..pooomff. A nearly invisible stream of glittering particles added some more centimeters to the pyramid...
Ingemar
-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: den 6 december 2004 13:50
To: TechNet E-Mail Forum; Ingemar Hernefjord (KC/EMW)
Subject: Re: [TN] late reaction on Brian Ellis response
Massive = quantity sufficient to initiate dewetting. My experience
(former 20th century incarnation) was that sulfamate nickel that had
just sufficient brighteners to make it look somewhat shiny (i.e., less
than mirror) would start to dewet. One also had to be careful with
stress reducers, as well. I can't be bothered to look up the
formulations, but my memory seems to tell me that many of the books used
to say "as needed" or words to that effect for all the organic
additives. I also remember conducting Hull cell tests on the Ni bath and
there was an optimum band in the middle of the cathode, so the "massive"
or "elephantine" quantity was dependent on current density and possibly
other parameters. Anyway, we always erred towards the minimum quantity
of organics that would do the job under our conditions of working. To
sum it up in one word: empirical.
We had a rat fall into the Ni bath one night. Try as we could with
massive quantities of carbon filtration etc, we could not get that bath
working again as we wanted. Had to scrap the lot in the end. Beware of
rodents :-)
Brian
Ingemar Hernefjord (KC/EMW) wrote:
> Had to rearrange a little, the ad-mini-strator reacted on something...
> posh machine, that robotic..
>
> ____________________________________________________________________________
>
> You were right, Brian.
>
> Matte Ni served well. When you say 'massive' below, I think of elep-hants.
> Can you expand your saying to something more like shi-t per volume or a
> similar scientific expression?
>
> Ingemar
>
>
> -----Original Message-----
> From: Brian Ellis [mailto:[log in to unmask]]
> Sent: den 1 september 2004 14:32
> To: TechNet E-Mail Forum; Ingemar Hernefjord (KC/EMW)
> Subject: Re: [TN] Tarnish Immersion Silver
>
>
> Ingemar
>
> I'm no expert here but, if the substrate permits the Ni to adhere
> perfectly, then I see no problem. OTOH, you will require plenty of Cl-
> ions to solder that darn nickel. It's probably a good thing that the Ni
> is matte, because it shows there is not a massive co-deposit of organic
> brighteners, which can cause dewetting. :-)
>
> Brian
>
> Ingemar Hernefjord (KC/EMW) wrote:
>
>
>>Brian in topform,
>> maybe one can slip in another finish question in parallel? Imagine packages made of Al/Si 58/42. They are ISO-1458 electrolytic sulphamate nickel plated (at least what we ask for). There is no P but lots of Cl, and the appearance of the finish is greyish and extremly matte, much like old cadmium plate. And extremly sensitive to fingerprints. The nickel plate ought to be solderable (filter feedtrues, SMA etc). Question: does the high silicon content have any impact on the final nickel plating?
>>
>>Ingemar Hernefjord
>>Ericsson Microwave Systems
>>
>
>
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