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Interconnects, speaker wire, power cords. Ask the Cable Guys.

RE: Scientist response about silver tarnish,plating material.

"There is a widespread misconception that silver oxidizes. This is incorrect. Silver does not oxidize at room temperatures. There also is an equally big misconception that silver oxide is a good conductor, thus tarnished silver connectors do not make a big difference. It is true that silver oxide is conductive, but the tarnish that easily develops on silver plated connectors is NOT silver oxide. Instead it is silver sulfide, brown to very dark brown (as opposed to pure black for silver oxide). Silver sulfide is not a conductor, but a semiconductor. Thus the idea that the silver tarnish does not affect the connection is a myth.

"Silver aggressively reacts with hydrogen sulfide, a gas that naturally occurs in the natural gas and also comes from cooking eggs (even fresh) and from the car exhaust. If you have none of these three sources in your area (unlikely), then your silver plated connectors would stay shiny for much much longer. [We might note that] platinum [and rhodium] does not tarnish or oxidize at any temperature (e.g. platinum plated spark plugs).

"It is a huge and widespread misconception that the choice of metal for plating has anything to do with its conductivity. The typical plating thickness is between 0.3μm and 11μm, give or take, plus has a substantial area of connection. Thus the contribution to the resistance of a thin cable several feet long is absolutely negligible.

"The choice of metal for plating is based on the anti-tarnish properties, wear resistance, reasonable conductivity (usually at least 15% of copper), adhesion to the base metal, and marketing of noble metals.

"Typical gold plating is done over a layer of nickel and thus essentially is just a nickel plating with a bit of extra protection from oxidation. Gold over copper is rarely used, because gold dissolves in copper. This makes a thin plating (less than 1μm) pointless while a thick gold plating is expensive. Test results show that a gold plating of less than 3μm does not protect well from harsh environments. Gold also is not very durable for frequent connections, especially as a thin plating.

"One of the most popular metals for high end plating today is rhodium. It can be applied directly over copper or silver, has a reasonable conductivity (like platinum), and does not wear (also like platinum)."

Another commentator notes "When silver contacts are used, one of the factors that make them good is that the silver is soft and when rubbed against the other contact, it cleans itself and smears, so good metal-metal contact can be sustained. However, if the contcats are not designed to do this, there could be a longer term problem with an accumulation of low conductivity sulfides and oxides. Basically, any potential loss in conductivity depends on the design of the contact."

Perhaps RCA plugs have a redeeming feature- the contacts do rub, so my silver-plated RCA's might be self cleaning, even thought they are browinsh.


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  • RE: Scientist response about silver tarnish,plating material. - mr.bear 01/10/1810:38:12 01/10/18 (0)

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