Gold Leaf Cementing on Copper Wire

[Geber]

The other day I observed something I didn't know was possible: gold leaf cementing on copper wire. I took some photos of it in this dirty, green Aqua Regia. A lot of times responses focus on going back to the tried and true methods. I can see the importance of that, but what about the theoretical aspects? I wonder why the gold fused into a piece as it cemented, and why the brown gold powder often doesn't have the appearance of gold that has been melted. Are there any methods of plating gold that require no anodic current but are simply Galvanic?

 

[4metals]

Are there any methods of plating gold that require no anodic current but are simply Galvanic?

Yes it is called immersion gold plating and it is very thin. Also referred to as ENIG which stands for electroless nickel immersion gold. Often used on circuit boards to produce an easily soldered to surface.

 

[Geber]

Has anyone seen leaf cement on copper like this?

 

[Yggdrasil]

Has anyone seen leaf cement on copper like this?

I have seen Pd float like this.
It was strange as it seemed emerge not on the Copper but on the surface.
So I guessed there was some kind of electron field (electrostatic?) that fed electrons to the salt so it dropped the valence to 0 and converted it to metal without actually directly contacting the Copper.

Or something else.

 

[Geber]

I have seen Pd float like this.
It was strange as it seemed emerge not on the Copper but on the surface.
So I guessed there was some kind of electron field (electrostatic?) that fed electrons to the salt so it dropped the valence to 0 and converted it to metal without actually directly contacting the Copper.

Or something else.

That is bizarre. I have seen you say that you must carry out cementation in acid, so that is a very difficult path for those electrons. In school I learned that two atoms must touch for a chemical reaction to take place, but I also believe chemicals can do strange things that no one understands, and that they might not always have the properties they are supposed to have.

 

[Yggdrasil]

That is bizarre. I have seen you say that you must carry out cementation in acid, so that is a very difficult path for those electrons. In school I learned that two atoms must touch for a chemical reaction to take place, but I also believe chemicals can do strange things that no one understands, and that they might not always have the properties they are supposed to have.

In my mind for a cementation mechanism to work it has to be sufficiently far a away from pH 7.
In this state there are enough ions and energy to let the exchange happen.