Is matching metals to avoid galvanic corrosion a lost cause?

[carat]

Because I have a bunch of static, permanently connected equipment, my intention was to match the plating of the contacts on the connectors to avoid galvanic corrosion (which I believe may have been leading to intermittent connections over time).

I had thought only gold and nickel were widely used, until I realized that the Neutrik XLR connectors I had assumed to be nickel plated were, in fact, silver plated. This has me second-guessing my whole scheme here. How many silver-colored connectors are actually silver, not nickel? How am I to differentiate silver from nickel plated connectors on equipment for which I cannot track down the exact model and spec of the jacks used? Is it a lost cause to even try?

 

[NTK]

Neutrik offers both silver or gold (hard gold over nickel) plating for their contacts (link).

With regard to galvanic corrosion, the anodic indices of gold, silver, nickel, copper, and brass are fairly close to each other (at the low end). In well controlled (i.e. dry and clean) environments, it should not be a big problem. Below from Wikipedia.

 

[sq225917]

All your sockets will be gold, so it doesn't happen. Silver will tarnish in any atmosphere with trace sulphur in the air, ie all air.

 

[carat]

All your sockets will be gold

I wish that were the case, but it is most definitely not. None of my Radial DI boxes have gold contacts in their sockets. Even on my audio interface there is a mixture of gold plated combi jacks and silver (nickel?) plated TRS jacks.

 

[RayDunzl]

I just use a little corrosion inhibitor here.

 

[Keith_W]

I didn't even think about it. Thanks to this thread, I went and inspected my copper spade plugs (at least, I think they are copper). They looked fine. How much of a problem is it? Do we have measurements to show loss of performance from corrosion?

 

[Doodski]

You could try some carbon conductive grease. We used it in a metrology lab a fair bit and the two engineers said it was better with grease.

 

[rationaltime]

You could try some carbon conductive grease. We used it in a metrology lab a fair bit and the two engineers said it was better with grease.

That is a great suggestion. Conductive grease becomes an important part of the signal path.
Maybe we should add conductive grease to the testing request list.

 

[Doodski]

That is a great suggestion. Conductive grease becomes an important part of the signal path.
Maybe we should add conductive grease to the testing request list.

Yes, that is a excellent idea. LoL... I had to read your comment 3 times to get it to click in my brain...LoL>> but a excellent idea for sure... Just need a tiny bit enough to coat the termination and not make a mess
@amirm can you test carbon conductive grease to see if connections are improved with using it?

 

[carat]

Why does Amphenol see fit to disclose the plating used on all of their their TRS plugs, but not for their TRS sockets? I must have spent 30 minutes trying to determine the contact plating for their ACJS-MHDC (which appears to be the part used for my UltraLite Mk5's rear jacks) to no avail. Their website and datasheets don't mention it anywhere. Mouser's page for that model says "Contact Plating: Tin", but I'm assuming that's referring to the solder pins. Found some other site saying "Contact Plating: Nickel", which is probably correct, but it's not the type of site I'd trust for accuracy. I just don't understand why they'd think it an important spec to specify on the male connectors but not the female.

EDIT: This catalogue says "Contacts / Plating (Jacks): Brass / Sn (Tin) over Cu (Copper)." Could it really be tin after all? Why on earth would they use nickel for their plugs and tin for their sockets in the same line...

Also, does anyone know why Neutrik would choose sliver of all things for plating pro audio plugs? As sq225917 said above, it's known to tarnish easily. It's harder than gold but softer than nickel, and nickel is so broadly used.

 

[somebodyelse]

Silver is also broadly used and has been for a long time. IIRC the tarnish is a cosmetic issue not an electrical one, at least for audio contacts. Silver is cheaper, so can have a thicker, more durable plating.

 

[MCH]

I think unless you live very close to the sea or similar you don't need to worry. Even then... I lived for 6 years at less than 400 meters from the beach and never found rust in any of my several, often dirty, connectors.

In any case, if you do care about having your connections pristine, member @dualazmak , who by the way knows one thing or two about chemistry, has posted very detailed descriptions of his connectors maintenance procedures, and I am sure he will be happy to answer your questions. See for instance here:

https://audiosciencereview.com/foru...sover-and-multichannel-dac.12489/post-1364698

 

[OldHvyMec]

How am I to differentiate silver from nickel plated connectors on equipment for which I cannot track down the exact model and spec of the jacks used? Is it a lost cause to even try?

Use terminal ends that you can verify with the seller for one. Second silver color is just that, a color. Silver is softer compared to nickel, SS, Sterling Silver,
chrome, (one I really dislike) Rhodium it's too darn hard to really get a great connection without really torquing it down or using a softer material (like copper)
along with. Ex; copper washers over Rhodium eyelets or Y spades.

I use copper, red copper, copper/silver clad, silver and sometimes I use gold plating if it's marine or very harsh conditions like a coastal sea spray. Contact enhancers always, and WIPE the excess off. A good sealer that dries and has something like 2000 (size) 100% graphite. I've used Never-Seez (nickel) and mixed in 2000 graphite with pretty good result. Thin with WD40 if you like, it will dry to the paste and STOP 99% of any barnacles from growing. Wolfer Coat is even higher on the pressure/temp scale (top 3% off all grease made), again add graphite.

I have .9999 silver #12 cable with .99999 silver spades that are 45+ years old. They were built/treated with contact enhancers before the pressure weld crimps.
Simple Nevr-Dull was used 2 or three time in all those years. They were/are teflon coated and were used in B36s. USAF surplus a partial 250ft spool was 50 bucks.

Great cabling and terminal ends are pretty cheap compared to the problems they can mechanically cause. I NEVER cheap out on cabling, I built cabling
for percussion drilling equipment and failure = liquidated damages. Mine didn't fail, period. Chopped in half or wound around a drill string (maybe) but
NEVER a failure behind build quality. I did use Rhodium in a lot in DC analog application/connections. That stuff is tougher than anything I've ever used.
Hell to crimp too, for the record. Hex screws if you have a choice and of contact enhancer in the barrels pre-assembly.

Regards

 

[dualazmak]

I think unless you live very close to the sea or similar you don't need to worry. Even then... I lived for 6 years at less than 400 meters from the beach and never found rust in any of my several, often dirty, connectors.

In any case, if you do care about having your connections pristine, member @dualazmak , who by the way knows one thing or two about chemistry, has posted very detailed descriptions of his connectors maintenance procedures, and I am sure he will be happy to answer your questions. See for instance here:

https://audiosciencereview.com/foru...sover-and-multichannel-dac.12489/post-1364698

Hello again, @MCH,

Thank you for your kind notice and referring to my post there.

Here, for reference and interest of OP and many people looking this thread, I need to add that @MCH and myself (both are Ph.D. scientists in chemistry-oriented field) had very nice and important discussion on cleaning materials/liquids for metal-to-metal connectors/contacts in our audio system; please refer to these posts on my project thread; #671, #675, #676, #677, #678, #680, #682, #683, #684.

Recentry, I also shared this post #895 and #906 again sharing my semi-annual cleaning of all the metal-to-metal connectors/contacts.

After my long-year experiences, and after havening the above nice invaluable discussion with @MCH, now I do believe that periodical intensive cleaning of all the metal-to-metal connectors/contacts, at least once in 6 months in my case, using pure IPA (isopropyl alcohol) and cotton swabs (with compressed paper rods) as well as micro-porous ceramic RCA cleaning kit would be the best way to keep "fresh and clean contacts for electricity/electron transmission".

Any (snake-oil-like?) cleaning liquid (contact restorer liquid/spray) containing antioxidant (and/or corrosion inhibitor) chemicals (such as oleic acid, other unsaturated fatty acids, ascorbic acid, sodium ascorbate, etc.) should be strictly avoided, at least in my audio system, since all of these antioxidant chemicals may have long-year-range possibility of plymerization into undesirable resins and/or acidic corrosions on metal surfaces.

 

[RayDunzl]

I guess I'm a little behind on my connector cleaning.

 

[Chrispy]

The only times I've had galvanic issues are on bikes with various metal interfaces, often exacerbated by lack of maintenance or just a bit of grease on installlation....