Here is a copy
of 4 pictures of real time aging of silver and copper.

The pictures
are:
(1)
Silver Spoon - 10 years in the bag (taken out for trade
shows - no polishing)
(2)
Silver Lead frame - 10 years - unprotected after 9 months
is also in the picture
(3)
Copper Bus Bar (3 feet long in a torn bag - no corrosion
after 7 years) - this
bar is represented in the Bus Bar graph that shows corrosion
after 7 days
(4) Integrated
Circuit Chip (IC Chip) -- this is a combination of the silver
lead frame (that forms the "feet" of the chip when
bent) and tin solder attaching the "feet" to the circuitry
(the black box) -- it is this multi metal point (where the tin
solder contacts the silver) where you get the worst corrosion.
This is a combination
of galvanic corrosion and atmospheric corrosion.
Galvanic corrosion occurs when you have two dissimilar
metals in contact with each other. The two metals set up an electrical connection
-- like biting aluminum foil with fillings in your teeth, what
you actually feel is electrical.
Intercept, being electrical in nature, actually blocks
this electrical connection between the two metals and acts as
a sacrificial electrode giving
itself up instead of the metals reacting -- thus stopping or
significantly slowing the galvanic corrosion.
Intercept needs to be in intimate contact for this two
work though, but no other material on the market (except using
zinc or an actual sacrificial circuit) can protect against
galvanic corrosion. The
unprotected IC chip corroded to this extent in the picture after
6 months -- the Intercept protected chip was 7 years. Quite a difference.
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