HP board "gold recovery" garbage

[Jon Elson]

On 01/23/2019 08:20 PM, ED SHARPE via cctalk wrote:
> I learn something  new  then... when   was  palladium used?   was it  around in  the  2100  hp  days or  was this   used  later?   and  I had not heard of  it?
>
If palladium was used, it was in VANISHINGLY small 
quantities.  Many circuit boards use palladium to seed the 
plating in the plated-through holes.  But, the amounts there 
are in the micrograms for a whole board.  I suspect if 
palladium was used in multilayer caps that it was used for 
the same purpose, a wash over the surface of the capacitor 
material, allow it to dry and then electroplate with the 
desired electrode material.  They'd probably use a couple 
milligrams at most on each layer of a capacitor sheet, which 
would eventually be cut up into hundreds of thousands of caps.
Some high-value MLCs can have 20 layers or so, so that would 
be milligrams * 20 / 100,000.
Not a hell of a lot of palladium would be in an entire board 
full of them.

Jon