Galvanic corrosion in connector contacts

[thefsb]

I recently learned that it may be a bad idea to plug, say, a gold plated 1/4" male TRS into an audio interface and leave it there since the female connector inside the interface is probably nickel plated rather than gold and the contact between the two will cause galvanic corrosion of the nickel-plated connector.

So, iiuc, this means that gold plating of connectors is not desirable in itself. Mating parts should preferably have the same metal plating.

Diuc?

 

[RayDunzl]

I might put a little corrosion inhibitor on the plug, and not worry about it.

 

[NTK]

Corrosions depend a lot on the environmental conditions. If it is in a dry environment, it is much less of an issue. When we talk about corrosions, we usually refer to electrochemical oxidation, which requires an electrolyte (i.e. water). Galvanic corrosions happen often in water pipe connections when dissimilar metals are in contact with each other, with water being the electrolyte.

The potential for corrosion depends on the difference between the anodic index of the two metals, with the metal with the lower anodic index being attacked. That's why we galvanize with zinc because it has a very low (negative) anodic index, and will act as the sacrificial element as zinc will be the metal that is corroded away first.

With a difference of 0.30 V in the anodic indices between gold and nickel, it is unlikely a problem unless it is in a very humid environment.

References: Wikipedia sections on anodic index and galvanic corrosion

 

[restorer-john]

I recently learned that it may be a bad idea to plug, say, a gold plated 1/4" male TRS into an audio interface and leave it there since the female connector inside the interface is probably nickel plated rather than gold and the contact between the two will cause galvanic corrosion of the nickel-plated connector.

I would be more concerned about leaving say a 1/4" adaptor (6.35-3.5mm) plug in a socket for the long term as the spring contacts will become tired and/or cause damage to the moulded socket housing.

I've replaced many headphone sockets over the years from fatigue due to plugs being left in. The sockets are designed to be inserted/released to almost help them self-clean.

Ray's suggestion of simply squirting a bit of contact cleaner on a rag and wiping the plug every now and then is the most sensible- I've been doing that for 40 years. I also clean the actual contacts in H/P sockets that haven't been used for a while- you'd be amazed at the audible contact improvement.

 

[solderdude]

Everything has been mentioned:
A: it IS environment dependent (moisture and even salty-air near the coast) and can be a problem when a DC current is flowing though it. Headphones do NOT have a DC flowing through it nor is there a 'circuit path' that would enable this.
B: Contacts can loose contact pressure over time
C: TRS contacts kind of clean themselves when inserting/pulling them out.
D: An occasional wipe with contact cleaner will help the plug, you can take a cotton swab and clean the socket.
E: 3.5mm TRS are more prone to issues (certainly the sockets) than a 6.3mm
F: Gold contacts also can get dirty. They do not corrode though.

So... just unplug and when the connectors become problematic give them a good cleaning or do it preventative say once a year or so.

 

[mansr]

Corrosions depend a lot on the environmental conditions. If it is in a dry environment, it is much less of an issue.

Well, some of us are in England. I once found this inside an iFi DAC that was behaving erratically:

 

[NTK]

Well, some of us are in England. I once found this inside an iFi DAC that was behaving erratically:

I grew up in south east Asia. With the hot and humid weather there plus the level of atmospheric pollution, electronics products (and other products too, e.g. molds and fungus growing in camera lenses) don't stay in their best shape for very long if they are not protected.

I completely agree with @ RayDunzl (and @ restorer-john) of applying contact cleaner to help protect (or slow down) corrosion of the exposed metal.

 

[thefsb]

Good info. Thanks!

 

[thefsb]

Well, some of us are in England. I once found this inside an iFi DAC that was behaving erratically:

is something missing in your post?

 

[RayDunzl]

At work, nothing was used (except alcohol cleaning) on gold card edges.

Plug-in power connectors, nothing.

Screw/bolt power connections, NO-OX-ID-A required per BellCore installation specifications.

This was for Telephone Central Office, when reliability was the number one consideration.

I have a multi-lifetime supply in the tool box.

https://www.sanchem.com/electrical-contact-lubricant.html

 

[mansr]

is something missing in your post?

Missing image? I the external link with an upload.

 

[thefsb]

At work, nothing was used (except alcohol cleaning) on gold card edges.

Plug-in power connectors, nothing.

Screw/bolt power connections, NO-OX-ID-A required per BellCore installation specifications.

This was for Telephone Central Office, when reliability was the number one consideration.

I have a multi-lifetime supply in the tool box.

https://www.sanchem.com/electrical-contact-lubricant.html

I've a lot of experience dealing with requirements from telcos and respect for the engineering that went into reliability and everything associated with it. So this quote means something, even if it is excerpted for NO-OX-ID marketing...

A quote from a Bell Systems manual on making a connection: "The mating surfaces of the connection shall be burnished to a bright metallic finish and coated with a thin layer of NO-OX-ID anticorrosion paste to preserve continuity indefinitely."