Electrical Contact Material

S

Searcher7

Guest
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.
 
Searcher7 wrote:
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.
In a critical situation I would use reed relays and small magnets.
Click to expand...
A totally closed system, no maintenance.
 
Searcher7 wrote:
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.
Oh, and if you insist on contact fingers, try hammered silver.
Click to expand...
It produces nice springs, and even the oxide conducts.
They might come to 4 dollars a piece, but satisfaction guaranteed.
 
On Dec 2, 10:11 pm, Searcher7 <Search...@mail.con2.com> wrote:
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.
Click to expand...
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.
 
"Searcher7" wrote in message
Can anyone tell me of any springy, corrosion resistant metals/allows
that don't need special plating to be used as contacts?
Click to expand...
Here is more than you will ever want to know about contacts made from
different materials...

Relay Contact Life...
http://relays.tycoelectronics.com/appnotes/app_pdfs/13c3236.pdf
 
On Thu, 2 Dec 2010 19:11:04 -0800 (PST), Searcher7
<Searcher7@mail.con2.com> wrote:

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).
Click to expand...
---
Platinum?

---
JF
 
On Fri, 03 Dec 2010 21:46:42 +0000 (GMT), Stuart
<Spambin@argonet.co.uk> wrote:

In article <fn7if6d82d17er3rrq6uneudb43db47cul@4ax.com>,
John Fields <jfields@austininstruments.com> wrote:
Platinum?

Not sure about Platinum but IIRC Rhodium was used for some special relays.
Click to expand...
---
What about platinum are you unsure of?

---
JF
 
John Fields wrote:
On Thu, 2 Dec 2010 19:11:04 -0800 (PST), Searcher7

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).

Platinum?

0.000050 gold flash over nickel, and it won't matter much which alloy
Click to expand...
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
 
Searcher7 wrote:

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).

What's the quantity? Is it a one-off? If so, just get a relay and hack it
Click to expand...
for the contacts.

For production, see my other post (gold-flash over nickel plate, or $olid
$ilver, BeCu for the springy part).

Cheers!
Rich
 
In article <fn7if6d82d17er3rrq6uneudb43db47cul@4ax.com>,
John Fields <jfields@austininstruments.com> wrote:
Platinum?
Click to expand...
Not sure about Platinum but IIRC Rhodium was used for some special relays.

--
Stuart Winsor

Midland RISC OS show - Sat July 9th 2011
 
On Fri, 03 Dec 2010 21:46:42 +0000 (GMT), Stuart <Spambin@argonet.co.uk>
wrote:

In article <fn7if6d82d17er3rrq6uneudb43db47cul@4ax.com>,
John Fields <jfields@austininstruments.com> wrote:
Platinum?

Not sure about Platinum but IIRC Rhodium was used for some special relays.
Click to expand...

Platinum is the most widely used switch contact media in use by man at
present.
 
On Fri, 03 Dec 2010 14:06:28 -0800, Rich Grise
<richg@example.net.invalid> wrote:

John Fields wrote:
On Thu, 2 Dec 2010 19:11:04 -0800 (PST), Searcher7

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).

Platinum?

0.000050 gold flash over nickel, and it won't matter much which alloy
the rest of the contact is. :)
Click to expand...
Total bullshit. Gold plating that thin is for cheap "Monster" brand
level stupid consumer products.

Mil contacts are NOT plated(pins and sockets)(switches are, but it is
VERY heavy plating), and yes,the underlying material WOULD matter as that
thin of a gold plating will be worn off after not too many cycles.
The reason Gold is chosen when it is, is because it, like Platinum, NEVER
oxidizes. If your "gold" contacts get a patina on them, they are NOT
gold.



Or, $olid $ilver ;-P
Click to expand...
Bad news, Silver will easily meld with itself, and electrical current
will actually help. High current will weld such a set of contacts
together in pretty short order.

And I'd use BeCu before I'd use phosphor bronze; just a personal
whaddayacallit. ;-)
Click to expand...
Phosphor Bronze is a bearing media, not an electrical switch contact
media. D'oh!

BeCu is used for elements that need to be light in weight or have
better corrosion properties, like phono cartridge needle arms, or the
switch contact's "arm". It is not a very good electrical contact face
media choice either.
 
On Fri, 03 Dec 2010 14:10:54 -0800, Rich Grise
<richg@example.net.invalid> wrote:

Searcher7 wrote:

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).

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).
Click to expand...
For production? For production you just buy a damned part. An SSR or
a switch based relay... even a miniature job. Hell, I have about ten in
my junk box here. Everything from sealed explosion proof mil jobs down
to opto-coupled micro-SSRs.

Sheesh.
 
On Dec 3, 5:10 pm, Rich Grise <ri...@example.net.invalid> 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
Click to expand...
Sjouke, I'll need to make almost 800 tiny contacts(for just the
initial prototype). And one end of each contact will to be soldered to
fingerboards that have .156" traces.

As for silver I heard the oxide could be a resistance problem. (And it
looks too expensive anyway).

George Herold, I just may have to plate anyway. :-(

Bill, That PDF wouldn't apply that much to me because what I'm making
will only entail making and breaking connections *when there is no
current*.

Stuart, I settled on Phosphor-Bronze because of what I thought would
be it's spring temper, corrosion resistance, and electrical
conductivity.(Not to mention cost).

John Fields, Platinum and Rhodium are too exotic to fit my parameters.

Rich Grise, As for why I didn't go with BeCu. One particular reason is
that I need the spring of Phosphor-Bronze. As many as 56 out the
almost 800 connections will have to be made at one time, and so I need
to come up with a flexible backing for the unsoldered ned of the
contacts to do this.

Thanks.

Darren Harris
Staten Island, New York.
 
On Dec 3, 5:10 pm, Rich Grise <ri...@example.net.invalid> wrote:
Searcher7 wrote:
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).

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
Click to expand...
Sjouke,

I'll need to make almost 800 tiny contacts(for just the initial
prototype). And one end of each contact will to be soldered to
fingerboards that have .156" traces.

As for silver I heard the oxide could be a resistance problem. (And it
looks too expensive anyway).

George Herold,

I just may have to plate anyway. :-(

Bill,

That PDF wouldn't apply that much to me because what I'm making will
only entail making and breaking connections *when there is no
current*.

Stuart,

I settled on Phosphor-Bronze because of what I thought would be it's
spring temper, corrosion resistance, and electrical conductivity.(Not
to mention cost).

John Fields,

Platinum and Rhodium are too exotic to fit my parameters.

Rich Grise,

As for why I didn't go with BeCu. One particular reason is that I need
the spring of Phosphor-Bronze. As many as 56 out the almost 800
connections will have to be made at one time, and so I need to come up
with a flexible backing for the unsoldered ends of the contacts to do
this.

Thanks.

Darren Harris
Staten Island, New York.
 
Searcher7 wrote:
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
Click to expand...
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.
 
Searcher7 Inscribed thus:

As for why I didn't go with BeCu. One particular reason is that I need
the spring of Phosphor-Bronze. As many as 56 out the almost 800
connections will have to be made at one time, and so I need to come up
with a flexible backing for the unsoldered ends of the contacts to do
this.

Thanks.

Darren Harris
Staten Island, New York.
Click to expand...
You're not making an electronic one arm bandit, are you ;-)

--
Best Regards:
Baron.
 
On Dec 4, 2:53 pm, whit3rd <whit...@gmail.com> wrote:
Searcher7 wrote:
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

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.
Click to expand...
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.
 
Searcher7 wrote:
As for silver I heard the oxide could be a resistance problem. (And it
looks too expensive anyway).
Click to expand...
That black tarnish isn't oxide, it's mostly sulfide, and it's almost
as conductive as silver is.

Cheers!
Rich
 
On Dec 4, 2:39 pm, Searcher7 <Search...@mail.con2.com> wrote:
On Dec 3, 5:10 pm, Rich Grise <ri...@example.net.invalid> wrote:





Searcher7 wrote:
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).

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

Sjouke,

I'll need to make almost 800 tiny contacts(for just the initial
prototype). And one end of each contact will to be soldered to
fingerboards that have .156" traces.

As for silver I heard the oxide could be a resistance problem. (And it
looks too expensive anyway).

George Herold,

I just may have to plate anyway. :-(

Bill,

That PDF wouldn't apply that much to me because what I'm making will
only entail making and breaking connections *when there is no
current*.

Stuart,

I settled on Phosphor-Bronze because of what I thought would be it's
spring temper, corrosion resistance, and electrical conductivity.(Not
to mention cost).

John Fields,

Platinum and Rhodium are too exotic to fit my parameters.

Rich Grise,

As for why I didn't go with BeCu. One particular reason is that I need
the spring of Phosphor-Bronze. As many as 56 out the almost 800
connections will have to be made at one time, and so I need to come up
with a flexible backing for the unsoldered ends of the contacts to do
this.
Click to expand...
We buy/ use some nice BeCu wave washers. BeCu can be springy too.

George H.
Thanks.

Darren Harris
Staten Island, New York.- Hide quoted text -

- Show quoted text -
Click to expand...
 
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