Edwin,
I don't have an answer to your question, but I have an aside you may find
interesting.  We have repeatedly found that exposure of electroless nickel
to RMA flux and solder (wave), followed by an Axarel clean, turns the nickel
a rather attractive black-navy color.  The coloration cannot be removed with
anything less than grinding off the surface, and no contamination can be
detected on the Ni surface.  Apparently the Ni is receiving a surface etch
which changes the surface spectral response, giving a dark coloration.

Just something to keep in mind .

Ralph Vaughan
Boeing-Atlanta

> ----------
> From:         Louis, Edwin[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Louis, Edwin
> Sent:         Monday, July 20, 1998 1:17 AM
> To:   [log in to unmask]
> Subject:      [TN] Analysis
>
>      Below is a question about solderability of electroless nickel.
>
>
> ______________________________ Forward Header
> __________________________________
> Subject: Analysis
> Author:  Edwin Louis at cmd-cs4-cc-p
> Date:    7/10/98 3:52 AM
>
>
>      Dan, here is the message I was trying to send to Peter.
>
>
> ______________________________ Forward Header
> __________________________________
> Subject: Analysis
> Author:  Edwin Louis at cmd-cs4-cc-p
> Date:    7/10/98 3:03 AM
>
>
>      Peter we have some electroless nickel on aluminum in which  some
> times
>      you can solder to it with Sn63 and RMA flux and other times you
>      cannot. Some people have suggested that there are  various plating
>      types per various specs. that incorporate higher or lower amounts
> of
>      phosphorus. The high phosphorus containing plating presumedly do
> not
>      solder as well as the lower content plating. Another difference I
>      understand is that sometimes there are impurities of organics that
>      interfere with the soldering or perhaps heavy metal impurities that
>
>      interfere with solderability. We would like to analyze and compare
> the
>      two types of plating for these impurities. What do you suggest and
> for
>      how many dollars?
>         It appears after conversation with Dan Sostak that perhaps Auger
>      would be best because phosphorus probably migrates to the surface
> as
>      do organics. Because of the surface soldering process the culprits
> are
>      probably on the surface. As far as trace included organics are co
>      ncerned, will microscopic FTIR fit the bill? I would appreciate
> some
>      guidance from you on this matter.
>
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