You could try simply locally heating an area of the board [with a hot air
gun or something].
The silver will tarnish whereas the Sn will melt, [The thinness of the
coating will make this hard to see though]
Better would be to get the supplier to identify the finish in a "dead" area,
[example the snap off bit in a multi up panel] but I suppose you already
thought of that.
Regards
Mike Fenner
Indium Corporation
T: + 44 1908 580 400
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Pb-free: www.Pb-Free.com
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Gabriela Bogdan
Sent: Thursday, September 09, 2004 6:39 PM
To: [log in to unmask]
Subject: Re: [LF] Tin and Silver Plating on PCB
If you want to do a destructive test like the one you suggested, you can try
the KOSLOW kit:
http://www.koslow.com/1598.html
Gaby
----- Original Message -----
From: "Bev Christian" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, September 09, 2004 6:52 PM
Subject: Re: [LF] Tin and Silver Plating on PCB
> Pratap,
> This is what I found via Google:
>
> Spot test for silver is: drip 1 drop concentrated nitric on coating and
let sit for 1 minute. Neutralize with 1 drop NaOH. A dark brown precipitate
indicates silver.
>
> I just tried this on a silver plated component I had handy and I think you
need to either dilute the nitric a bit or not leave it very long because one
drop for one minute will eat through any immersion or electroplated coating!
It does turn black though when you add the NaOH. CAUTION: both conc nitric
acid and sodium hydroxide solutions are not fun solutions in the first place
and mixing them together, even at the drop level must be done with caution.
You will of course have toasted your board.
>
> I found no readily available spot test paper for silver.
>
> One other method, NOT inexpensive, but non-destructive is SERA testing.
> http://www.ecitechnology.com
>
> Bev Christian
> Research in Motion
>
>
> -----Original Message-----
> From: Pratap Singh [mailto:[log in to unmask]]
> Sent: September 9, 2004 10:40 AM
> To: [log in to unmask]
> Subject: [LF] Tin and Silver Plating on PCB
>
>
> Technetters,
>
> It is hard to distinguish visually a tin plated PCB vs a silver plated
> PCB. Do you know some process that can be implemented at incoming
> inspection to separate these two platings. In general silver plated PCB
> is a bit brighter than tin plated PCB. Any help is appreciated.
>
>
> _____________________
> pratap singh
> Tel./Fax: (512) 255-6820
> email: [log in to unmask]
> www.rampinc.com
>
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