Silver and dribble....
It's legacy WWII English radar gear dregs... prior to NASA/Space race of the post war era, there were no good gold plating baths available for plating connectors that wouldn't KILL you... silver was the next best option, as it's oxide remains conductive and when plated sufficiently thick, it is soft enough to maintain fairly good air-tight seals in clamping and screw type connectors.
During the '50's and '60's, Sandia/Argonne/JPL/USGov't sponsored heavy research into better gold processes, culminating in the current acid based buffered hard gold systems meeting gov't and electronics requirements.
So blame silver connectors on the war.... if you've got 'em, keep 'em away from sulfur and skin...
Of course nickel isn't used in relay contacts... why would you? wrong material for the wrong application... duhh
😉
Juergen Knoop said:
It's legacy WWII English radar gear dregs... prior to NASA/Space race of the post war era, there were no good gold plating baths available for plating connectors that wouldn't KILL you... silver was the next best option, as it's oxide remains conductive and when plated sufficiently thick, it is soft enough to maintain fairly good air-tight seals in clamping and screw type connectors.
During the '50's and '60's, Sandia/Argonne/JPL/USGov't sponsored heavy research into better gold processes, culminating in the current acid based buffered hard gold systems meeting gov't and electronics requirements.
So blame silver connectors on the war.... if you've got 'em, keep 'em away from sulfur and skin...
Of course nickel isn't used in relay contacts... why would you? wrong material for the wrong application... duhh
😉
Speaking of silver contacts, there's an interesting article (PDF file here) about distortion in connectors used for high-power microwave applications and how to minimize it. This is at frequencies for which the plating thickness is multiple skin depths, so I'm not sure sprouting a woody when thinking about this for audio applications is called for 🙂.
Still, it's an interesting article.
Still, it's an interesting article.
Skin effect on audio frequencies may be considerable on conductors meters of thickness. Like in that positron vacuum tube photo of which Demian posted. 😀
Re: Gold plating
I really like your expert input. Now I got the answer why some of my gold plated connectors were heavily corroded with a layer of copper oxide.
Cheers,
Edmond.
auplater said:
I really like your expert input. Now I got the answer why some of my gold plated connectors were heavily corroded with a layer of copper oxide.
Cheers,
Edmond.
That's inflation for you. She used to only charge $15. I hear it's cheaper over in Richmond.
SO, what is wrong with nickel for relay contacts? Please tell me, because I have plenty of what looks like nickel plated BNC connectors. Why there, and not relay contacts? This is where your expertise could be really useful, Auplater! Show us what can't work, not criticize what costs too much, in your opinion.
Re: Re: Gold plating
I agree
I think that auplater has a lot of good posts.
Cheers
Edmond Stuart said:
I agree
I think that auplater has a lot of good posts.
Cheers
john curl said:Well, your friend is my friend, Stinius.
I know that John.😉
Maybe we should go out fishing some day?
Cheers
nickel barrier
Nickel contacts? Auplater was talking about a nickel middle layer, i.e. a barrier. That's a whole different story.
Cheers,
Edmond.
john curl said:
Nickel contacts? Auplater was talking about a nickel middle layer, i.e. a barrier. That's a whole different story.
Cheers,
Edmond.
Stinius, I try to tell what I have found from experience. Not BS. You start the thread. I don't want to confuse what I do, with what others think that I do.
john curl said:
Hi John,
I don't know, I'm not an expert in this field. I only wanted to point out that (probably) it makes a big difference if nickel is used as barrier against corrosion/diffusion or as a contact interface (i.e. used as surface layer).
Cheers,
Edmond.
why not??? here's why...
well... for one thing, non-plated nickel has an oxide barrier on it that develops a high (and unstable) surface contact resistivity, ... you know.. ohms/square that sort of thing...
http://www.esdjournal.com/techpapr/ohms.htm
so contacts made with it as a final surface would not be reliable.... the problem only gets worse with nickel plating... as this is never 100% nickel in industry... always has co-deposited carbon, sulfur, etc. to promote leveling and improved reflectivity. This then totally changes the surface chemistry (it's why plated nickel can be a tough solder) not to mention the sheet and bulk resistivity as well...
As for BNC connectors... that's done because inickel plating levels and brightens faster than any other plated metal... and we all know how alluring those bright and shiny surfaces are 😉 😀
really has nothing to do with functionality from an electrical pov, other than reasonable corrosion resistance and hardness...
for reliable contacting surfaces.. you want ruthenium, iridium, platinum... maybe tungsten... stuff with a high melting/arcing resistance... low oxygen affinity so stable over time... that sort of thing...
cheers!!
BTW: I make a killer chocolate-porter home brew... 😀
John L.
john curl said:
well... for one thing, non-plated nickel has an oxide barrier on it that develops a high (and unstable) surface contact resistivity, ... you know.. ohms/square that sort of thing...
http://www.esdjournal.com/techpapr/ohms.htm
so contacts made with it as a final surface would not be reliable.... the problem only gets worse with nickel plating... as this is never 100% nickel in industry... always has co-deposited carbon, sulfur, etc. to promote leveling and improved reflectivity. This then totally changes the surface chemistry (it's why plated nickel can be a tough solder) not to mention the sheet and bulk resistivity as well...
As for BNC connectors... that's done because inickel plating levels and brightens faster than any other plated metal... and we all know how alluring those bright and shiny surfaces are 😉 😀
really has nothing to do with functionality from an electrical pov, other than reasonable corrosion resistance and hardness...
for reliable contacting surfaces.. you want ruthenium, iridium, platinum... maybe tungsten... stuff with a high melting/arcing resistance... low oxygen affinity so stable over time... that sort of thing...
cheers!!
BTW: I make a killer chocolate-porter home brew... 😀
John L.
So, a copper with low percentage of an oxygen is a good material for binding posts, but not for wires, right?
As soon as a banana tip is soldered to it, it's advantage goes to zero?
As soon as a banana tip is soldered to it, it's advantage goes to zero?
99.99999999 pure &^%#$
no... the problem is most all copper used for electronics is already low oxygen... Even if you buy special OFHC grades... it's still cheap relative to what the connector folks are charging you for the finished product...
all the 6 nines pure ofc pablum is designed by marketing people to separate your wallet from its contents... 😉 😉
John L.
Wavebourn said:
no... the problem is most all copper used for electronics is already low oxygen... Even if you buy special OFHC grades... it's still cheap relative to what the connector folks are charging you for the finished product...
all the 6 nines pure ofc pablum is designed by marketing people to separate your wallet from its contents... 😉 😉
John L.
Alchemy (OT)
Hi John.
Although I'm not totally unfamiliar with electroplating, to me, the rationale behind those additives was always a mystery, a kind alchemy. I once had to build a water cooled cathode of lead. So I electroplated lead upon copper tubing. To get the right surface constitution it was advised to add 'agar agar' to the electrolyte.
Normally, agar agar is used as culture medium for microbiological work. Go figure.
Cheers,
Edmond.
auplater said:
Hi John.
Although I'm not totally unfamiliar with electroplating, to me, the rationale behind those additives was always a mystery, a kind alchemy. I once had to build a water cooled cathode of lead. So I electroplated lead upon copper tubing. To get the right surface constitution it was advised to add 'agar agar' to the electrolyte.
Normally, agar agar is used as culture medium for microbiological work. Go figure.
Cheers,
Edmond.
- Status
- Not open for further replies.