24 Jan
2019
24 Jan
'19
8:28 a.m.
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