Gold plated pins in sulphiric cell

[Michel D]

Hello,
I placed some pins in a sulphiric cell; the gold comes off fast, but there seems to be a other layer under it.
I washed the pin's in 3different bath of water en leth them stay in the last bath... one day lather the layer seems te be almost desolved and the copper becomes vissible...
anyone have an idea what the layer could be?

 

[4metals]

Could the base material be brass which is copper plated before the gold plating layer? Gold strips fast and the yellow brass may be showing through.

 

[Michel D]

Could the base material be brass which is copper plated before the gold plating layer? Gold strips fast and the yellow brass may be showing through.

When I cut the pins in 2, its complet red copper inside not brass.
It really seems to be a layer that have been plated on the copper before the gold was plated on it... i did a bleach test on it and it turns "black", but not as black as I see on the other silverplated stuff that I tested before...

 

[Shark]

Nickel is a fairly common sublayer before plating over copper and brass.

 

[FrugalRefiner]

If you are referring to the bright, white color, as Shark said, it is probably nickel. Gold has an annoying habit of migrating into copper, which slowly reduces the amount of gold on the surface, thus lessening the anti-oxidizing effect. So, copper and brass items are very often plated with a thin coat of nickel before being plated with gold, since gold does not migrate into the nickel.

Dave

 

[4metals]

From my old electroplating days mil spec gold always was copper, nickel and gold to prevent migration. Other non military applications were often just copper base plate with gold over it.

 

[Marcel]

Usually there is nickel beneath the gold then copper.