On Tue, 11 Dec 2012 22:06:24 -0800, Searcher7 wrote:

I'm working on a project that is a mechanical switch of sorts, and it
entails running electrical signals through Phosphor-Bronze contacts.

Now since *all* alloys will oxidize to an extent, I was wondering if I
were to wipe the phosphor-Bronze contacts with the same
material(Phosphor-Bronze), would that be serve to keep the alloy's
surface clean? (The wiping action will be part of the mechanics of the
switch).

Wow. No one who actually knows is answering. Here's my two bits, but
take them with a large grain of salt, 'cause I'm no expert.

I know that "wiping action" is an advertised feature on many switches.

There is probably some minimum normal force that you want to achieve to
make sure that the oxide is wiped off, and probably some minimum wiping
distance to boot. I absolutely couldn't tell you what the necessary
forces and/or distances are, but I'll bet you that there's standards out
there, and probably huge amounts of tribal knowledge at the various
switch manufacturers.

If you can get a good thick silver plating on your contacts then your
required forces will go way down -- silver is a pretty good conductor,
and silver oxide is both mechanically weak and (I understand) not a bad
conductor in its own right.

Finding a switch that has about the same ratings as what you need, taking
it apart, and copying it's actions and forces may not be a bad way to
go. You won't be able to duplicate their metallurgy, but you can't have
everything.

You might try asking this question on sci.electronics.design, since you
don't seem to be getting much info here.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com