Mike,

Thanks very much for the links. They furnished quite a bit of
information about silver, its alloys, and its salts, that I didn't know.
They do seem to support what I had thought about sulfide being more
common than oxide, and added chloride to the list of common tarnishes.
And maybe the reason for the elusiveness of information on the
conductivity of silver oxide is because of the strange nonlinear effects
reported in the first paper. Hopefully Jim will be able to fill us in
about that, since he apparently has some information on the oxides. I'm
frankly startled that any oxide can have conductivity within even a few
orders of magnitude of a good pure metal, so I hope he'll post the
information soon. One of the links notes that only silver alloys
(particularly with copper) tend to oxidize, so in order to get a coating
of silver oxide, you'd need to coat your wire not with pure silver, but
with an alloy that's somewhat more resistive than copper to begin with.
Does that mean, Jim, that the conductivity of the plated wire would
actually improve as it oxidizes?

A paper I read some time ago showed that silver plating nearly always
consists not of pure silver but of some alloy (as one of the links
pointed out), and nearly all those alloys have a conductivity less than
copper -- some, much less. So if you want to reap whatever benefit there
might be in silver corrosion products over copper ones, you'll have to
put up with lower conductivity in the uncorroded wire. Seems to me to
make more sense to use enameled or insulated copper wire to begin with,
but I guess some folks think the appearance of silver is worth the hassle.

The only resistivity information I have is for AgS, which is apparently
a common corrosion product, and its resistivity is about 100,000 times
as great as silver. This isn't necessarily bad, since both a perfect
conductor and a perfect insulator provide a lossless coating. The loss
incurred by conductors of intermediate quality depends on the frequency
and coating thickness, so it can be hard to draw conclusions about what
compound might be better than another except in a specific case.

Roy Lewallen, W7EL

Mike Coslo wrote:

Roy Lewallen wrote:

Ah, finally, someone who knows what the conductivity of silver oxide
is. Although I believe silver sulfide is much more common than oxide,
I've been able to find the conductivity of the sulfide but not the
oxides. Just what are the conductivities of the silver oxides (AgO and
Ag2O)? Which are we most likely to find on the outsides of wires? Are
they really more common than the sulfide?

Roy Lewallen, W7EL



An interesting and eventually amusing link on silover sulfide


http://www.eecs.cwru.edu/misc/AMANDA...er_revised.doc

another:

http://www.brushwellman.com/alloy/tech_lit/sep02.pdf


and this:

http://nepp.nasa.gov/whisker/reference/tech_papers/chudnovsky2002-paper-silver-corrosion-whiskers.pdf


It is interesting that the NASA paper refers to silver sulfide as
non-conductive, while the first paper gives a short and tantilizing
tidbit about forcing it into conductivity.

Hope you find the links interesting!

- Mike KB3EIA -