Electrical Contact Material

Can anyone tell me of any springy, corrosion resistant metals/allows that don't need special plating to be used as contacts?
The contacts will only carry data and low voltages(ie: +5, +10, +12,+24, -5).
And there will be no wiping between contacts, but there will also be no current unless the contacts are together. So no arcing problems.
The best I've been able to come up with is Phosphor-Bronze. (Beryllium- copper was my second choice).
Thanks.
Darren Harris Staten Island, New York.
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Searcher7 wrote:

In a critical situation I would use reed relays and small magnets. A totally closed system, no maintenance.
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Searcher7 wrote:

Oh, and if you insist on contact fingers, try hammered silver. It produces nice springs, and even the oxide conducts. They might come to 4 dollars a piece, but satisfaction guaranteed.
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What's wrong with plating? It's not that expensive. Maybe nickel plating. (We got a tray full of stuff for <$100 ) You want something that won't oxidize. A little gold flash would be perfect, but I've no idea how much that costs.
George H.
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On Thu, 2 Dec 2010 19:11:04 -0800 (PST), Searcher7

--
Platinum?

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Not sure about Platinum but IIRC Rhodium was used for some special relays.
--
Stuart Winsor

Midland RISC OS show - Sat July 9th 2011
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On Fri, 03 Dec 2010 21:46:42 +0000 (GMT), Stuart

--
What about platinum are you unsure of?

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John Fields wrote:

0.000050 gold flash over nickel, and it won't matter much which alloy the rest of the contact is. :-)
Or, $olid $ilver ;-P
And I'd use BeCu before I'd use phosphor bronze; just a personal whaddayacallit. ;-)
Cheers! Rich
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Searcher7 wrote:

What's the quantity? Is it a one-off? If so, just get a relay and hack it for the contacts.
For production, see my other post (gold-flash over nickel plate, or $olid $ilver, BeCu for the springy part).
Cheers! Rich
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Searcher7 wrote:

That's a perfect storm: no high voltage, no wiping, means that any dust mote will prevent contact. That can only work reliably if you have high contact forces, or if you use reed switch parts (for the sealed glass envelope).
One possibility you might consider is zebra-stripe elastomer conductors; these are compliant enough to make a connection even if that dust mote shows up.
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Zebra-stripe elastomer conductors would be too "exotic", expensive and would require a lot of redesigning, *if* they would work for what I'm doing.
I might however be able to incorporate wiping if I can determine a good material to use, outside of the contact material itself.(I can make it part of the switching mechanics).
Thanks.
Darren Harris Staten Island, New York.
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cross out to reply "Searcher7" wrote in message wrote:

Zebra-stripe elastomer conductors would be too "exotic", expensive and would require a lot of redesigning, *if* they would work for what I'm doing.
I might however be able to incorporate wiping if I can determine a good material to use, outside of the contact material itself.(I can make it part of the switching mechanics).
Thanks.
Darren Harris Staten Island, New York.
Good nickel plated brass should do. As an example, for a gas furnace with a millivolt relay, I had problems with a standard "Decora" switch designed for 120V. There was enough surface oxidation to cause an open circuit at such low voltages (about 500mv max) A 12V automotive switch with good wiping and pressure works well. I replaced the Decora switch with another of the same type but with nickel plating and have had no problems since then.
Don Kelly
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Well, unless nickel plating means I'll never have to worry about "dirty" contact problems, I'll stick with Phosphor-Bronze + wiping to keep things clean.
Thanks.
Darren Harris Staten Island, New York.
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And can anyone suggest a material I can use for wiping? (A material that isn't conductive).
Thanks.
Darren Harris Staten Island, New York.
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?"Searcher7" wrote in message wrote:

And can anyone suggest a material I can use for wiping? (A material that isn't conductive).
Thanks.
Darren Harris Staten Island, New York. ----------------------------------- Nickel plating so far has gone for over 13 years without a problem while the standard switches lasted under a year. Gold plating works but is expensive As to "wiping" that is a function of the way the contact is made- the contacts rub a bit when closing. This acts to clean them. No need for external wiping with some cloth or emery.
Don Kelly cross out to reply
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Contact "wipe" is the term used for how much the contact travel overlaps and is not a material.
After a contact initially touches any further action will cause the contact arm to bend and thus "wipe" or scrape the contact bump against the other contact side bump. This effectively keeps the contact surfaces clean and free of dust specs between the mating surfaces.
For reliable contacts the usual techniques are bifricated (dual arm ends and contact surfaces), dual contacts in parallel, silver or gold (best) contact surfaces, seal them in a dust enclosure or vaccum (best= no dust or oxide), wet them with mercury or other liquid conductor (slow acting) or any of the above in combination. The arms need to be a different material for spring action.
If you want to actaull wipe a contact clean use isopropylene or a good isopropyl alcohiol with low water or oil content and a good lint free cloth wrapped around a contact burning tool, or just a burning tool designed for that usage.
Reed relay contacts are sealed in a vacuum bottle and can be operated via a magnetic field.
And can anyone suggest a material I can use for wiping? (A material that isn't conductive).
Thanks.
Darren Harris Staten Island, New York.
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wrote:

--
Do you have a reference where 'wipe' is defined as a distance?
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Masterfully spoken.
Now, if only he would discontinue top posting.
I am reminded of Rodney King's words... :-|
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I've noticed that when questions are asked responders tend to fall back on what is tried and tested, and they give answers in line with what is proven with whatever application they *think* is being referred to. There is no problem with that, but if someone is thinking outside of the box there is resistance to the new idea, even though the project is not completely understood by everyone else.
There is no need to explain the project. (And it would do no good anyway without pictures).
So basically, the question is simple. But for some reason no one here is getting it. They instead jump on me for not explaining it completely.
I can only conclude that no one yet knows the answer and so I am in uncharted territory as far as what I need. So I will have to experiment with various solid materials in order to find one that will relatively easily scrap the oxide off of phosphor-Bronze so a electrical connection can be reliably made at the voltages I mentioned.
P.S.: I'll say this. The device I'm designing will incorporate a wiping motion *between* when the connections are made, so the actual wiping will not occur between one contact and another, but *before* they come together, which is why I am looking for a different non- conductive material for wiping.
Thanks.
Darren Harris Staten Island, New York.
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In article

That makes things clearer.
I'm now just trying to visualise the arrangement you are proposing.
--
Stuart Winsor

Midland RISC OS show - Sat July 9th 2011
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