I would avoid it.

Conventionally:
Epoxy has poor adhesion to tin and its alloys
The tin/silver interface will give an inter-reaction at the bondline
leading to electrical opens although you may retain mechanical
adhesion. One/Two years is a long time in this situation especially if
you have mechanical stress/vibration or any temperature swings in
service.
This is very well documented in the literature and you should see
something in the Technet archives.

More open mindedly:
There are some companies working on this and there are now products
which claim to have solved this problem, either by using a sort of
halfway house product (adhesive with a fusible metal filler basically)
or by special undisclosed ingredients/formulations.
Contact suppliers for the latest



Mike


 ----- Original Message -----
From: "Marsico, James" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, January 23, 2001 8:34 PM
Subject: [TN] silver epoxy & solder coated parts


> Hello, Technet...
>
> Here is an unusual situation.  We have to assemble a surface mount
assembly
> using silver epoxy.  Some of the components will be solder coated.
I know,
> don't bother asking... this is the way it has to be.  The good thing
is that
> this assembly is a prototype for bench-top laboratory use only.
There is no
> harsh environment and needs to operate 1, maybe 2, years.  The
question is
> does anyone foresee any problems?  What happens when one mixes toe
two
> technologies?
>
> Thanks,
> Jim Marsico
> EDO Electronic Systems Group
> [log in to unmask] <mailto:[log in to unmask]>
>

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