I have noticed that almost all the electrical and electronic contacts I've been using are silver-coloured. I'm thinking of clips, probes, small plugs and sockets, component legs, and a good proportion of cable. I imagine this is for corrosion resistance, since the bare copper items I've used have not retained their good surface conduction for very long (particularly if handled). But, what metal(s) do they use for these things?

(I have seen gold plate too, which is supposed to be better, but I'm not sure what it's being compared with.)

 

They use Beryllium Copper, Bronze, Copper Alloy, Phosphor Bronze, and Spring Brass. Alloys with tin and nickel are also used.

 

Thanks for the information. I'm still a little confused though, because I'd expect most of those to be copper- or gold-coloured. Would that be correct? Am I just coming across the tin and nickel based ones?

 

I'm not sure about the colors I just went to a connector manufacturers website to get the names, from the horses mouth, so to speak.

 

(I have seen gold plate too, which is supposed to be better, but I'm not sure what it's being compared with.)

Gold is widely used as an electrical conductor plating because of its resistance to oxidisation and its generally good electrical characteristics (i.e. low resistivity). The major drawback of gold is that its expensive, however engineers feel that the cost is warranted where the need to remove the oxidisation effects is significant. For this reason gold-plating is widely used in the aircraft industry on many/most electrical contacts.

Dave

 

Most of the copper alloys (brasses and bronzes) will be a gold, reddish gold, or brown color. Many brasses and bronzes have good corrosion resistance - especially phosphore bronze and silicon bronze. Tin and nickle have good corrosion resistance also, but cost more. Silver has even better corrosion resistance, but costs more still.

Silver has an additional advantage - arcing less than many copper alloys when a contact is made or broken.

 

Dave: That makes sense. And I've also seen gold quite often on audio connectors.

thingmaker3: That's what I thought regarding colour - thanks for confirming. So, if the connectors are silver-coloured, they must be using something based on tin, nickel or silver.

 

http://materials.globalspec.com/Lea...ponents/Electrical_Contacts_Contact_Materials