Why not Silver?

[aboos]

I'd be interested to learn the conductivity of copper oxide (that's what I'd call oxidated copper - I don't know how else to name it, in light of recent post: copper sulphate perhaps?).

Kind regards,
HK

Silver oxide is a good conductor while almost all other metal oxides are either isolators or semiconductors.

While silver is reacting with sulphur (from SO2 in the air), copper is forming oxides. There are two oxide variants. One of them is a good semiconductor and was used in he early times of electronics as a material to build rectifiers long before germanium and silicon were used.

 

[Charles Darwin]

I suspect that noble metals (ie those that you can dig out of the ground in their pure form) do not readily form oxides.

 

[aboos]

That's the reason for nickel, rhodium, gold and platinum top layers on contact surfaces especially for harsh environmental conditions.

The reason for using silver especially for RF is its conductivity which is much better than e.g. gold. Despite the fact that it is not as noble as the above mentioned metals it is the only metal not leading to contact loss when oxidizing

 

[lcsaszar]

I researched the web and found that silver does not oxidize, but tarnishes with sulphide. I read somewhere that electrical conductivity of silver sulphide at room temperature is about 1000 times that of copper.
I am sure that thin layer gets abrased when the contact surfaces are sliding on each other.
I treat my connectors with contact lubricant, and never had any problem.

 

[davidsrsb]

Silver suphide causes noise in RF connections when the electrons tunnel through the very thin sulphide layer

 

[aboos]

Silver sulphide is an isolator. That's the reason why contacts get worse and why it causes noise. As it can easily wiped of, it is normally no issue if contacts get plugged and unplugged frequently. Otherwise, the connection must be protected from air (e.g. contact oil)

 

[johnsurnamerobinson]

Years ago I had phono plugs flashed with silver they went Black in my coal fire heated home.Very easy to clean off with sodium bicarbonate and Aluminium foil.

 

[Charles Darwin]

Alloys are interestingly counterintuitive.

Gold is a good conductor but if you mix it with silver the conductivity goes down until the alloy is 50% gold and 50% silver.
Then it goes up again the more silver you mix in until you have pure silver.